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Androgens

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Male sex hormones

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Androgens

  1. 1. ANDROGENS M.Prasad Naidu MSc Medical Biochemistry, Ph.D.Research Scholar
  2. 2. Male sex hormones  Androgens or androgenic hormones  Testosterone, androsterone, dehydroepiandr osterone  Androsterone is the first to be isolated  The main commercial source of androgens: urine of male , female and testicular extract  Androgens also produced in A. Cortex  Testosterone is the most potent
  3. 3. Biosynthesis  Cholesterol  Testis, adrenal gland & ovary  Production & release stimulated by : ICSH  Acetate  Cholesterol  pregnolone  progesterone  testosterone
  4. 4. Metabolism  Liver  Principal metabolites: 17-ketosteroids  17-KS give colour reactions such as Zimmermann (m-dinitrobenzene) and Pincus ( antimony trichloride) reactions  17-KS are of 2 types  1. neutral and acidic
  5. 5. Reactions involved in androgen metabolism  1. conversion of C17 –OH group to the keto group  2. reduction of 4,5 double bond  3. reduction of ketonic group at C3  4. conjugation with glucuronic acid or sulphuric acid  Most imp 17-KS isolated from urine are androsterone, etiocholanolone, dehydroepiandroste rone, epiandrosterone.  The amt of 17-KS increases with age and in pregnancy
  6. 6. Metabolism  Abnormally high 17-KS are found: in increased adrenocortical function, increased interstitial cell function  Slight increase of 17-KS found in: acute illness, starvation, anoxia, physical or mental stain, exposure to cold and post- operative state  Low values : hepatic diseases, chronic illness, anemia, malnutrition, malignancy decreased amt of gonadotropic and adrenocorticotropic hormones
  7. 7. Functions  Testosterone is the most active  Testosterone > androsterone > dehydroepiandrosterone > epiandrosterone  Promotes growth and function of the male accessory sex organs, viz prostate gland, seminal vesicles, Cowper’s glands and penis  Development of 20 sex characteristics viz texture of skin, distribution of hair, voice etc  Promotes protein syn in accessory organs  Increase the activity of glycolytic enzymes  Decrease the activity of alk.phosphatase, glutamic dehydrogenase & hepatic arginine synthetase
  8. 8. Functions  Increase the rate of synthesis of FAs  Increase the rate of production of fructose by the seminal vesicles  Increase the rate of synthesis of citrate  Increase respiration ( O2 consumption and CO2 production ) of the seminal vesicles and of the prostateincrease the tubular reabsorption of citrate, Na, K, Cl-, SO4 2-, PO4 3-
  9. 9. Hormones of Corpus luteum hormones  Pregnancy hormones / Gestogens  Progesterone is the most imp of this group  Secreted by corpus luteum part of ovary  Degraded to inactive pregnanediol  Main source : corpus luteum  Also found in placenta, pregnancy urine, and adrenal cortex
  10. 10. Biosynthesis  Acetate   Corpus luteum , adrenal corted, testes and placenta  It is secreted a day or two earlier, or on the day of ovulation from the corpus luteum  Its secretion is stimulated by prolactin  It is bound in plasma to the corticosteroid-binding globulin (CBG)  The principal excretory product of progesterone is pregnanediol formed by the reduction of Progesterone
  11. 11. Functions  In conjunction with estrogenic hormones, it prepares the uterine mucosa for the reception of fertilized ovum  Maintains the conditions for its further growth  Exhibits antiovulatory property ( used as oral contraceptive)  In conjuction with estrogen, progesterone causes development of the alveolar system of the breast  Increases the BMR  Effects electrolyte and water metabolism
  12. 12. Relaxin  Another hormone from corpus luteum, placenta and uterus  Found in blood of pregnants  Chemically it is PP (mol.wt 90,000)  Mammary development in rats  Anti-diuretic effect in rats

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