endocrine - repro Flashcards
isoform of 5a-reductase:
Expression starts at puberty
Type 1
Testosterone and DHT synthesis
Aldrostenedione to testosterone (17B-HSD) to DHT (5a-reductase)
isoform of 5a-reductase:
Found in skin - contributes to sebaceous gland activity and acne formation
Type 1
isoform of 5a-reductase:
Found in male urogenital tract, skin, hair follicles and Liver
For masculinization of ext genitalia in utero
Type 2
Leydig cell produces estrogen peripherally. Effects…
Bone maturation
Insulin sensitivity
Improves lipoprotein profile (increase HDL)
60% of androgen is bound to
sex hormone binding globulin SHBG
Androgen negative feedback effect on FSH and LH ..more on
LH
Regulation of Sertoli cell function
Stimulated by both testosterone and FSH
Expresses FSH receptor
FSH stimulates synthesis of inhibin
Loophole in male repro axis..
Intratesticular T level should be >100x more than circulating T level to maintain normal spermatogenesis
Exogenous T level increases circulating T only
True
Regulation of development of internal genitalia in male
Wolffian duct-Testosterone and presence of MIS
Regulation of development of internal genitalia in female
Mullerian duct - absence of MIS
Regulation of development of external genitalia in male
Presence of DHT
Regulation of development of external genitalia in female
Absence of DHT
GnRH neurons have been demonstrated in the feral hypothalamus by
9wks gestation