Effects of intratesticular injections of estradiol and gonadotropin-releasing hormone (GnRHA, HOE 766) on plasma androgen levels in intact and hypophysectomized Torpedo marmorata and Torpedo ocellata.
The effect of a gonadotropin-releasing hormone analog (GnRHA, HOE766) was studied in hypophysectomized elasmobranch fish Torpedo marmorata and T. ocellata. In addition, estradiol (E2) effects were studied in intact and hypophysectomized (HPX) animals. Plasma androgen concentrations were measured 2 or 6 hr after GnRHA (100 ng or 10 micrograms) or 6 hr after E2 (10(-9) or 10(-6) M) intratesticular injections. Both GnRHA and E2 induced the increase of plasma androgen levels in HPX fish. E2 also enhanced androgen levels in intact animals. It is concluded that GnRH-like substances and E2 may modulate testicular activity in elasmobranch fish.
Fasano
S
S
Institute of Biology, I Faculty of Medicine, University of Naples, Italy.
Pierantoni
R
R
Minucci
S
S
Di Matteo
L
L
D'Antonio
M
M
Chieffi
G
G
D000728:Androgens / Q000032:analysis / Q000097:blood*; D000818:Animals; D004958:Estradiol / Q000494:pharmacology*; D007016:Hypophysectomy; D008297:Male; D010906:Pituitary Hormone-Releasing Hormones / Q000494:pharmacology*; D013737:Testis / Q000187:drug effects*; D014101:Torpedo
D000728:Androgens; D010906:Pituitary Hormone-Releasing Hormones; D004958:Estradiol