Here is a compilation of essays on ‘Types of Hormones’ for class 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Types of Hormones’ especially written for school and college students.
Essay on the Types of Hormones
- Essay on Pituitary Hormones
- Essay on Adrenal Hormones
- Essay on Pancreatic Hormones
- Essay on Sex Hormones
- Essay on Testicular Hormone
i. Growth Hormone:
Pituitary gland is known as the “master gland” because it performs a number of important functions in the body and controls the functioning of a number of other endocrine glands. Without the anterior lobe of the pituitary gland, the sex functions and growth cease, and the functions of the adrenal cortex, the thyroid and the parathyroids decrease considerably. The anterior lobe produces at least six hormones.
Growth hormone (GH) is used successfully in stimulating growth in hypopituitary dwarf and to treat other forms of retarded growth. An interesting diagnostic application of human GH is based upon its ability to increase the concentration of free fatty acids in the blood. The effect to increase blood glucose concentration has been used in the treatment of hypoglycemia in children.
The nitrogen-sparing anabolic effect has been employed to suppress catabolism from burns and other severe traumatic conditions. Other potential uses of GH are the stimulation of hematopoiesis and post menopausal and other types of bone demineralization, the treatment of renal failure, obesity, hyperlipidemia, immune disorders, aging and hypothalamic hypofunction.
ii. Gonadotropic Hormones:
Preparations of FSH from human pituitary glands or menotropins from the serum of postmenopausal women, administered along with LH or human chorionic gonadotropin induce ovulation in women suffering from diminished gonadotropin secretion.
Human chorionic gonadotropin is used for stimulation of androgen secretion by testicular interstitial cells, and for expediting the descent of the testes in boys and young men with cryptorchidism (non-descent of testes into scrotum). This hormone is also effective in prolonging luteal function and in inducing ovulatory cycles in anovulatory women with metrohia hemorrhagica. HCG induces ovulation only when a mature ovarian follicle is present.
iii. Thyrotrophic Hormone:
Thyrotropic hormone sustains the activity of thyroid gland. In the absence of TSH, the thyroid gland atrophies, producing only small amounts of thyroid hormones. Excess of TSH causes hypertrophy and hyperplasia of the thyroid, and a clinical condition similar to Grave’s disease. In Grave’s disease an abnormal thyrotrophic substance is present in the blood. Because of its long duration of action, it is called long-acting thyroid stimulator (LATS).
This substance is a globulin belonging to immunoglobulin G class. It is an antibody to TSH, which is capable of mimicking its antigen. It differs from TSH in passing through the placenta and its secretion is not suppressed by the thyroid hormone. This non-suppressiblity is the basis for a diagnostic test for hyperthyroidism.
Therapeutic Uses of Pituitary Hormones:
This is the human growth hormone, a polypeptide containing 191 amino acids. It is obtained from recombinant DNA directed synthesis. The hormone is administered intramuscularly.
b. Chorionic Gonadotropin:
Human chorionic gonadotropin is a gonad stimulating polypeptide hormone obtained from the urine of pregnant women. It is a white, amorphous powder, freely soluble in water. This hormone alone cannot induce ovulation in anovulatory women. However, if it is used with Menotropin, which favors maturation of ovarian follicles, ovulation can be induced.
The hormone is effective in treatment of female infertility due to luteal hypoactivity. The drug is also used in treatment of male sterility, as it stimulates testosterone secretion in the male. To achieve full spermatogenesis in hypogonadotropic eunuchoidism, the hormone is used in combination with menotropins or clomiphene.
In cryptorchidism, chorionic gonadotropin promotes descent of testes, if they are retractile. HCG is used as a diagnostic tool to assess the cause of delayed puberty in males, to test the responsiveness of the testes to gonadotropins.
Adrenocorticotropic hormone (ACTH) is a polypeptide hormone produced by the corticotroph cells of the anterior pituitary gland. This hormone-increases the rate of secretion of the adrenal corticosteroids.
Commercially, this hormone is prepared from the pituitary glands of sheep, hog, beef and whales. There are two types of preparations, short and long acting. The short acting preparation consists of a lyophilized powder of a stable aqueous solution containing 1% phenol.
The powder is dissolved in physiological saline or some other suitable medium. The preparation is administered intramuscularly or intravenously. Long acting preparations are covered by a gelatinous menstruum so that the rate of absorption is delayed and its effectiveness is prolonged. It is injected intramuscularly.
This hormone stimulates the adrenal cortex to secrete hydrocortisone, desoxycortisone and androgens. ACTH is used as a diagnostic drug to assess the functional capacity of the adrenal gland. Increase in plasma Cortisol or urinary 17-hydroxycorticosterone shows a normally functioning gland.
The hormone is effective in all of the conditions for which glucocorticoids are found useful. It is considered to be superior to glucocorticoids in the management of acute exacerbations of multiple sclerosis and inflammatory bowel disease. It is also used as an antiemetic during cancer chemotherapy and severe myasthenia gravis.
This is an extract of postmenopausal urine containing the follicle stimulating hormone and luteinizing hormone in equal amounts. This has the gonadotropic activities of FSH and LH and is used to induce ovulation in women with infertility consequent to deficiency of endogenous production of gonadotropins. The ovulatory rate can be increased to 98% along with chorionic gonadotropin. The hormone is injected intramuscularly.
The posterior lobe of the pituitary gland contains two peptide hormones, Oxytocin and Vasopressin. Oxytocin is produced by the paraventricular nucleus while vasopressin is synthesized by the supra-optic nucleus. The two hormones flow down through the axons and are released at the nerve terminals.
Human and most mammalian vasopressin is called as arginine vasopressin while that obtained from the pig is known as lysine vasopressin (lypressin). Vasopressin is usually called antidiuretic hormone (ADH). When ADH secretion is reduced, a watery diuresis follows.
Defect in the secretion of hypothalamic adrenocorticotrophin releasing hormone and pituitary ACTH, diabetes incipidus results. Vasopressin is used for its antidiuretic effect in this disease. Due to its stimulatory effect on the vascular smooth muscle and increasing bowel movement, this hormone is used to treat bowel stasis and to expel gas after surgery. The vasoconstrictor and bowel spastic actions have, special use in stopping hemorrhage from peptic ulcers.
Oxytocin stimulates the contraction of smooth muscle in the uterine wall and alveoli of the lactating mammary glands. At the time of intercourse, the peristaltic movements of the uterine smooth muscle help in the movement of the spermatozoa. During parturition, the hormone stimulates and increases uterine contractions.
Vasopressin is the first synthesized peptide hormone. The synthetic product is identical in biological properties to the purified natural hormone. The successful synthesis of the natural hormones has provided opportunities for the synthesis of a number of analogues of both oxytocin and vasopressin.
A number of chemical compounds containing one or more amino acids replaced or additional to the natural hormone have been prepared and their pharmacological properties have been studied. One such product is vasotocin containing the pentapeptide ring of oxytocin and the tripeptide side chain of vasopressin. This substance possesses the properties of both the hormones.
e. Desmopressin Acette:
This substance is known as vasopressin, 1-(3-mercaptopropionic acid) 8-D-arginine, monoacetate trihydrate, a synthetic analog of 8-arginine vasopressin in which the amino group has been removed from the N-terminus cysteine and L-arginine at 8th position is replaced by the D-enantiomer.
It is a white fluffy powder soluble in water and alcohol. This substance is used in the treatment of central diabetes incipidus and to test the capability of kidney to concentrate urine. It can be used as a nasal solution or injection.
Lypressin is vasopressin, 8-L-lysine. It is isolated from hog pituitary glands and synthetically prepared. Lypressin is used in the control or prevention of diabetes incipidus. It possesses strong antidiuretic but weak pressor activity.
This substance is 8-L-Lysine or arginine vasopressin. It is used as an intramuscular or intravenous injection to control central diabetes incipidus due to its antidiuretic action.
Actions of Adrenocorticosteroid Hormones:
The adrenocortical hormones perform four different types of actions:
(i) Sodium ions are retained in the extra-cellular fluid and potassium ions within cells, so that blood volume and pressure are maintained,
(ii) Promote glycogenesis in liver and help in maintaining normal glucose levels in blood,
(iii) Tissue protein mobilization is increased and gluconeogenesis from amino acids is enhanced, and
(iv) They have androgenic effects from androgenic steroids, mainly dehydroepiandrosterone, from the adrenal cortex.
More than 50 steroids are present in the adrenal cortex. Only seven of them exert a significant glucocorticoid and mineralocorticoid effects. The anti-inflammatory activity of adrenal corticoids in man correlates well with their glucocorticoid activity. The undesirable side effects of retention of sodium and edema are related to mineralocorticoid activity.
Synthetic steroid compounds possessing higher glucocorticoid and lower meneralocorticoid activity than the natural hormones, cortisone and Cortisol have been prepared and marketed. All adrenocorticosteroids require the presence of a keto group at carbon atom 3 and a double bond between the carbon atoms 4 and 5. Additional unsaturation in ring A increases their anti-inflammatory and antirheumatic properties.
Simultaneously, it reduces the sodium retaining effect. Prednisolone possesses 4 times the anti-inflammatory property of Cortisol and has only 0.8 of the mineralocorticoid activity. The presence of oxygen at carbon atom 11 is essential for significant glucocorticoid activity but not for mineralocorticoid activity.
The 11 β-hydroxyl group is more potent than the 11-ketogroup, therefore, in the body, the 11 keto group is converted into β-group in the body. The 11 α-group is also important for glucocorticoid activity. The 21-hydroxyl group is necessary for mineralocorticoid activity. Mineralocorticoid activity can be considerably reduced without decreasing the glucocorticoid activity by introducing a methyl or hydroxyl group at 16th carbon atom.
Therefore, paramethasone, betamethasone, dexamethasone and triamcinolone have no significant mineralocorticoid activity. Glucocorticoids have powerful anti-inflammatory and immunosuppressant effects. They have permissive effect on the activity of other hormones and inhibit membrane lipid peroxidation.
Therapeutic Uses of Adrenocorticosteroids:
The adrenal hormones are used for replacement therapy in adrenal insufficiency like Addison’s disease. Both glucocorticoids and mineralocorticoids are used. Glucocorticoids are used to treat rheumatic, inflammatory, allergic, neoplastic and other disorders.
The anti-inflammatory actions of the glucocorticoids are used in the treatment of non-infectious acute ocular inflammation (iritis, choroiditis, conjunctivitis, sympathetic ophthalmia). Glucocorticoids are also used in decreasing some cerebral edemas and bacterial meningitis.
Glucocorticoids, help to reduce infantile massive spasms. Intranasal application is useful in curing chronic non-infectious rhinitis, acute bronchial asthma and obstructive pulmonary disease. Topical or systemic glucocorticoids are used in the treatment of certain skin diseases like psoriasis, dermatitis herpetiformes, eczema, pemphigus, exfoliative dermatitis and mycosis fungoides.
Due to the immunosuppressive action of the glucocorticoids, they are used to provide relief in nephritic syndrome, ulcerative colitis, myasthenia gravis and multiple sclerosis. The incidence and severity of the respiratory distress syndrome in premature infants is reduced by glucocorticoids.
a. Replacement Therapy:
Replacement therapy is used to cure primary and secondary adrenal insufficiency in which both glucocorticoids and mineralocorticoids are useful. The dose and dose-interval are variable from patient to patient. Doses are small and complications are not frequent.
b. Chronic Low Dose Systemic Therapy:
In mild inflammative or collagen disorders, low doses of glucocorticoids are sufficient and preferred because adverse effects are of low intensity.
c. Chronic High Dose Systemic Therapy:
In serious chronic inflammatory or immunologic disorders or in glucocorticoid responsive neoplasia, large doses of gluocorticoids are given for long periods of time. This leads to side effects and suppression of pituitary adrenal axis. These can be overcome by administering the doses in the morning or by giving twice the usual daily dose on every alternate day. Glucocorticoids with 12 to 36 duration of action are used in this therapy.
d. Intensive Short Term Systemic Therapy:
Large doses of glucocorticoids are given in certain acute conditions like bacteremic shock or status asthamaticus. The duration of the treatment is 48 hours.
e. Local Treatment:
The efficacy of topical application of glucocorticoids is dependent upon the inherent glucocorticoid activity of the steroid preparation, the concentration in the preparation, permeability the medium and local metabolism. Low potency steroids are usually applied due to their less severe adverse effects.
Therapeutically Used Steroid Hormones:
It is a derivative of prednisolone synthesized from steroid intermediates. This substance is a white or cream-colored powder slightly soluble in water but soluble in alcohol and acetone. It has 500 times higher topical anti-inflammatory activity of dexamethasone but is less active as a systemic glucocorticoid. This substance is used in the treatment of bronchial asthma and noninfectious rhinitis.
Betamethasone is prepared from 16-dehydropregnenolone by treatment with methyl magnesium iodide. It is a white crystalline powder soluble in alcohol and chloroform. It is a highly potent corticoid with minimum side effects. Other such preparations include Betamethasone acetate, Betamethsone benzoate, Betamethasone sodium phosphate and Betamethasone valerate.
iii. Cortisone Acetate:
Cortisone acetate is prepared by using easily available starting materials such as ergosterol, cholesterol or desoxycholic acid. Cortisone is converted to cortisone acetate by esterification with acetic anhydride. It is a white, crystalline powder insoluble in water but soluble in alcohol and chloroform.
Cortisone is a natural glucocorticoid with slight mineralocorticoid activity. Cortisone acetate is used along with desoxycorticosterone acetate in adrenocortical insufficiency. It is also used for all the purposes for which corticosteroids are used.
The preparation of this substance is similar to that of Betamethasone except that the 16 – methyl group is inserted in the α- configuration. It is also a white crystalline powder insoluble in water but soluble in alcohol and chloroform. It possesses glucocorticoid properties.
Therefore is used as an anti-inflammatory and antiallergic drug. It is applied topically in the treatment of glucocorticoid responsive dermatoses. It is used systemically to reduce hearing loss due to bacterial meningitis. Dexamethasone is also used due to its effect to suppress pituitary adrenocortical function in differential diagnosis of Cushing’s syndrome.
Hydrocortisone is commercially obtained from diosgenin. It is the main natural glucocorticoid in man and is the prototype of all the glucocorticoids. There are various preparations of hydrocortisone such as hydrocortisone acetate, cypionate, sodium phosphate and sodium succinate which are used for various purposes of glucocorticoids depending upon their solubility and penetration.
Progesterone is converted to the 6α-methy derivative and through a series of reactions into methylprednisolone. It is a glucocorticoid with actions, uses and effects typical to a drug of this class.
Prednisolone is prepared from hydrocortisone. It is also a typical glucocorticoid with the same type of uses. Prednisone is derived from cortisone. It is a dehydrogenated derivative of cortisone and is used for the same purposes typical of a glucocorticoid. The various preparations are used depending upon their potency as a glucocorticoid and their actions as mineralocorticoids.
This hormone is obtained by extraction of beef, sheep, pig and whale pancreas. Human insulin is obtained by chemically converting pig insulin. It can also be obtained by Eischerichia coli into which the human genes for insulin are inserted. The recombinant product possesses the same physiological properties of insulin. Insulin is also produced synthetically.
b. Zinc Insulin:
Zinc insulin is obtained by addition of appropriate quantities of zinc salts to insulin and crystallizing the compound. In this way a higher degree of purification can be achieved. It is used in diabetics who are allergic to insulin injections.
c. Insoluble Insulin:
Insoluble insulin is obtained by combining insulin or zinc insulin with globin or protamine to yield complexed of larger molecular weight. The advantage of insoluble insulin is that it goes into solution very slowly.
Glucagon is produced by the alpha cells of the islets of Langerhans. It exerts an opposite effect to that of insulin and increases blood sugar level. Therefore, it is known as hyperglycemic factor (HGF). It plays an important role in the physiological regulation of blood glucose and defects in the control of glucagon secretion are a factor in certain types of diabetes mellitus.
Glucagon is a polypeptide. It is used as a hydrochloride. Glucagon is a white crystalline powder soluble in dilute acids and alkalis. It is used to terminate hypoglycemic coma that may occur with high doses of insulin. It is used to diagnose glycogen storage disease and to determine pancreatic b-cell secretory reserve. Glucagon is also used as an adjunct in hypotonic radiography of the gastrointestinal tract to relax the smooth muscle.
ii. Insulin Injection:
This is a sterile, acidified or neutral solution of insulin. The solution has a potency of 40, 80, 100 or 500 insulin units in each ml. It is used mainly in the treatment of diabetes mellitus. Various modifications of insulin are prepared to suite either slower and long lasting action or faster action.
In the long and slowly acting types are Isophane Insulin suspension, which is intermediate acting; Insulin Zinc suspension, acting for intermediate duration and Extended insulin zinc suspension, that is long acting and Protamine zinc insulin suspension that is also long acting. The rapid acting variety is prompt insulin zinc suspension.
The thyroid gland controls the energy metabolism of the body and certain non-energetic metabolic functions. Thyroid hormone is used clinically to replenish the hormone level during conditions of thyroid insufficiency and not to increase the metabolic rate. The active principle of the thyroid gland consists of four active substances.
Thyroxine (tetraiodothyronin, T4) constitutes 75% secretion of the thyroid gland in the plasma. The remaining 25% is the less active diiodothyronine. Triiodothyronine is 3-10 times more active than thyroxine and forms only 3% of the plasma. Thyrocalcitonin decreases plasma calcium concentration and osteoclastic activity, thus inhibiting the mobilization of bone minerals into blood.
Calcitonin is a polypeptide isolated from the parafollicular cells of the thyroid gland in mammals and ultimobranchial gland of birds and fish. It contains 32 aminoacids. Calcitonin is a white fluffy powder highly soluble in water. It is used in hypercalcemia to bring blood calcium to normal level. It causes a favorable change in bone structure in Paget’s disease. In combination with calcitriol and calcium, it is effective against senile and postmenopausal osteoporosis.
The thyroid gland from domestic animals used as food is cleaned of fat and connective tissue, dried and powdered. It has yellowish color, meat-like odor and saline taste. The congenital absence of the thyroid gland hormones results in Cretinism. In childhood or adults, lack of thyroxine causes myxoedema.
Thyroid hormones are used therapeutically in the treatment of these diseases. The preparation is used to suppress the secretion of thyrotropin in nonendemic goiter and chronic lymphocytic thyroiditis (Hashimoto’s disease). Thyroid is given to patients with chronic constipation, menstrual disorders, sterility, arthritis, etc. associated with low metabolism.
Sex hormones can be divided into three groups:
(i) Estrogenic hormones,
(ii) Progestational hormone, and
(iii) Androgenic hormones.
The first and second groups of hormones are collectively known as ‘ovarian hormones’. The natural estrogens are steroid compounds containing 18 carbon atoms. The 3 and M carbon atoms are oxygenated. Progesterone produced by the corpus luteum contains 21 carbon atoms and has an α, β-unsaturated ketone in ring A. The naturally occurring androgens are 19-carbon atom compounds. The ring A is partly or completely saturated and a hydroxyl or keto group is attached to carbon atoms 3 and 17.
The ovaries secrete two main types of hormones, which are very closely related to the process of sex development and function. The first type of hormones is the group of steroids called estrogens. The second type is the luteal or progestational hormone called as progesterone.
The secretion and release of the ovarian hormones is regulated by the pituitary gonadotropins. The control of pituitary gonadotropins, in turn, is controlled by the estrogens and progesterone. In women ovulation can be prevented by estrogens due to suppression of FSH production. Very large doses of progesterone also inhibit ovulation due to inhibition of the production of the hypothalamic luteinizing hormone-releasing hormone.
Progesterone can also bring about infertility by maintaining the endometrium in a hypoproliferative and hyposecretory condition that is not favorable for implantation of the fertilized egg. Some progestins have an antifertility effect at doses much below than the necessary doses to suppress endometrial proliferation and secretion.
Ovarian Hormones and Contraception:
Estrogens and progestins are used in oral contraceptives. Interest on oral contraceptives started with progestins. Application of progestins alone leads to intermenstrual bleeding and this can be stopped with the addition of estrogens. Although estrogens favor endometrial proliferation, they have a hemostatic effect on uterine bleeding. Estogens not only help in normalizing the cycle of bleeding but also contribute to the contraceptive effect.
Although in earlier days it was believed that estrogen alone was responsible for the antifertility effect and progestin only promotes a normal menstrual cycle. However, no a days, it is realized that progestin alone can be contraceptive in low doses and it does not disturb the menstrual cycle of the users.
Progestins do not have the side effects like nausea, vomiting, headache and signs of venous thrombosis but they are less effective contraceptives than estrogens. Progestins are combined with estrogens in oral contraceptives in such a way that anovulatory doses of estrogen are followed in sequence by a progestin so as to stimulate the sequence of hormone dominance during estrous cycle and therefore to allow a near normal menstrual cycle.
Therapeutic Uses of Sex Hormones:
Estrogens are used in substitution therapy in cases when menopausal symptoms occur in normal menopause or due to ovariectomy. This administration of estrogens gives relief from a number of symptoms characteristic of the menopause. Low doses of estrogen treatment ameliorate the symptoms of vasomotor instability, hot flashes, prevent urogenital atrophy in menopausal women and prevent or slow down menopausal osteoporosis.
Estrogens are used in young women who suffer from failure of steroidogenesis. Treatment increases development of uterus, the appearance of secondary sexual characteristics and subtle biochemical and behavioral changes. Local application of estrogens is useful in the treatment of atrophic or senile vaginitis, vulvovaginitis and cervicitis due to hypoestrogenesis.
Estrogens are used in the treatment of a number of menitrual irregularities like amenorrhea. They are valuable in decreasing electrolyte imbalance, headache, tension, breast engorgement and nipple tenderness in premenstrual tension. By cyclic therapy estrogens are used in the treatment of dysmenorrhea. In endometriasis estrogens are effective for a short duration. In dysfunctional uterine bleeding, estrogens and progesterone combined treatment is very useful.
Estrogens suppress FSH release and inhibit blastocyst implantation, they are used as contraceptives. Other uses of estrogens include prevention of habitual abortion, induction of parturition and breast engorgement after parturition.
Estrogens decrease the plasma cholesterol level. Therefore, they are used as hypocholesteremic drugs. Acne vulgaris and hirsutism can be treated by estrogens. In males growth of prostatic cancer can be treated with estrogens. In women carcinoma of the breast and parts of the reproductive tract can be treated with estrogens.
A number of derivatives of estrogens are used depending on their efficacy through the oral route and injections. Among the derivatives are estrone, ethinyl estradiol, estradiol benzoate and estriol. Conjugated estrogens retain much of their activity on oral administration and are used extensively. Synthetic estrogens like diethylstilbestrol possess most of the activity of the natural hormones and are cheaper. Further, as they do not lose their activity through oral route, they can be taken orally.
This hormone is isolated from ovarian follicular fluid and from placenta. It is the most potent of the natural estrogenic hormones. Estradiol is prepared by reducing the 17-keto group of estrone. Estradiol is used in replacement therapy during post menopause, ovarian hypofunction and after ovariectomy. Estradiol is used topically in the vagina to cure atropic vaginitis. Derivatives of estradiol include estradiol valerate and estradiol cypionate.
Progesterone is the second type of hormone secreted by the ovaries. Progesterone has a unique physiological function. The minute glands present in the uterine wall are transformed into secreting glands under its influence. This is necessary for the implantation of the fertilized egg and for the continuous development of the placenta. For its activity, an estrogen is essential. In the absence of the estrogen or progesterone without estrogenic activity, the uterine wall atrophies.
Progestins change the cervical secretions to suppress a process known as ‘ferning’ in which cervical mucopolysaccharides crystallize to form dendrite. If the cervical mucus is not changed into the dendritic form, it forms a tight network of fibers to prevent the passage of spermatozoa through cervical opening.
The antifertility effect of progestins is partly due to their ability to suppress ferning. High doses of progestins inhibit the pituitary release of luteinizing hormone and the hypothalamic LHRH so as to prevent ovulation. They decrease uterine motility contributing to contraceptive effect. Other actions of progestins include antagonizing the endometrial actions of estrogens and stimulation of the development of the glandular portions of the mammary glands.
Progestins are used cyclically in the treatment of infertility due to the non receptivity of the uterus to implantation. The progestins sustain the secretory endometrium during the third and fourth weeks of the menstrual cycle.
Progestins are also used along with estrogens cyclically to treat secondary amenorrhea and dysfunctional uterine bleeding. They are also used to reduce premenstrual tension. Their effect to suppress the release of LH and LHRH is used in the prevention of ovulation in contraceptives and primary dysmenorrhea and endometriasis.
Progestins along with estrogens are used in sexual infantilism in the female to bring about genital development and maturation. Progestins are also useful to reduce breast size in mastodynia. Some of the commonly used progestins include progesterone, hydroxyprogesterone caproate, levonorgestrel, medroxyprogesterone acetate, megestrol acetate, norethindrone, norethindrone acetate, norethynodrel and norgestrel.
Testis performs two important functions. The first is the production of spermatozoa and second is to secrete male hormone, testosterone. Testosterone is produced by interstitial cells or Leydig cells and is responsible for the androgenic functions.
It controls the following activities:
(i) Testosterone is converted into the active metabolite, dihydrotestosterone. This metabolite stimulates and maintains the secondary sex organs namely, the penis, prostate gland, seminal vesicles, vas deferens and scrotum,
(ii) Testosterone exerts sustaining effects on the spermatogenic cells,
(iii) It stimulates the development of bone, muscle, nerves, skin and hair growth,
(iv) Testosterone is responsible for controlling the emotional responses to produce the characteristic adult masculine characters,
(v) It regulates the release of LH by the pituitary gland, and
(vi) Testosterone antagonizes the effects of estrogens and for this reason, it has clinical application.
Androsterone and testosterone are the naturally occurring androgens derived from androstane. The most commonly used androgenic steroids are the esters of testosterone (Testosterone propionate) and derivatives (methyltestosterone).
These substances, in addition to their androgenic actions exert anabolic effects and helps in the retention of calcium. Separation of the androgenic activities from the anabolic effects is useful in administration of the hormone in women. Therefore, a number of compounds with high anabolic and androgenic ratios are prepared and marketed.
In replacement therapy, testosterone is used in men with hypogonadism like eunuchism, and Klinefelter’s syndrome. The hormone is useful in the development of adult masculine characteristics in cases where the adolescent process is delayed. In non-descent of testes (cryptorchidism) androgens are used in combination with gonadotropins. Androgens are also very useful in hypopituitarism and Addison’s disease.
Cases of frigidity and impotence are also treated with androgens. Low doses of androgens are used in pituitary dwarfism to promote growth. Large doses of anabolic steroids increase athletic performance and aggressiveness.
Androgens help to relieve vasomotor instability in postmenopausal women. Due to their antiestrogenic action, androgens provide relief in dysmenorrhea. Other uses of androgens are in the treatment of endometriasis, suppression of lactation and breast cancer.
Testosterone is extracted from the testes of animals. Commercially, it is synthesized from cholesterol. It is a white crystalline powder insoluble in water. It is not effective orally as it is metabolized in the liver. Testosterone cypionate is derived from testosterone. It has much longer duration of action than testosterone if administered intramuscularly with oil. Testolactone is derived from progesterone or testosterone by microbial transformation.
The advantage of this substance is that it does not possess the androgenic activities. It is used in the adjunctive and palliative treatment of inoperable breast cancer. Stanozolol is an androgen with strong anabolic and weak androgenic activities. It is used to promote nitrogen anabolism and after serious infections, burns, trauma, or surgery.
Fluoxymesterone is derived from methyltestosterone. It is five times more potent than testosterone and is orally effective. Methyltestosterone is derived from dehydroepiandrosterone. It is effective orally and combined with various estrogens for treatment of menorrhagia, menopausal symptoms, dysmenorrhea, osteoporosis and to suppress postpartum lactation.