Biochemistry-Hormones Of Gonads Flashcards
Where does testosterone synthesis takes place?
Leydig cells
the rate limiting step in testosterone synthesis uses what transport protein?
Steroidogenic acute regulatory protein (StAR)
What is the predominant hormone during fetal development?
Testosterone
What is the predominant hormone after birth and before puberty?
Androsterone
What is the normal rate secretion of testosterone in adult male?
5mg/ day
In transport of gonadal hormones, the sex hormone binding globulin has higher affinity to:
Testosterone or estrogen
Testosterone
Sex hormone binding globulins are produced by the liver and increased by EXCEPT: A. Estrogen B. Liver disease C. Hyperthyroidism D. Hypothyroidism
D
What is the primary function of SHGB
Restrict free concentration of testosterone in the serum
What is the active form of testosterone in seminal vesicle and prostate?
DHT
What catalyzes the conversion of testosterone to DHT?
5a-reductase
DHT predominantly expressed in the liver
Type I
Testosterone synthesis is regulated by
Negative feedback
LH stimulates testosterone production in _____________by enhancing rate of cholesterol side-chain cleavage
Leydig cells
FSH binds to sertoli cells and promotes synthesis of ___________ to transport testosterone in very high conc to site of spermatogenesis
ABP
Hormone produced by sertoli cells that inhibit FSH synthesis and secretion
Inhibin
Which has higher affinity to receptor? DHT or Testosterone?
DHT
Esterification of ______ produce more lipid soluble anabolic steroids
17b- hydroxyl group
Testosterone propionate
T cypionate
Enanthate
Anabolic steroid that slows catabolism by the liver
Alkylation at 17a position
Finasteride and Dutasteride are used in treatment of benign prostatic hyperthrophy by inhibiting
5a- reductase
Hypogonadism due to defective gonadothropin secretion
Secondary
Testicular feminization syndrome with feminized external genetalia is due to defect in
Testosterone receptor
A disease due to increased DHT or T particularly in older males which leads to difficulty in urination
Benign prostatic hypertrophy
The primary estrogen from the ovaries
Estradiol E2
An estrogen formed from androstenedione
Estrone E1
