Indirect evidence for a physiological role exerted by a "testicular gonadotropin-releasing hormone" in the frog, Rana esculenta.
The possible physiological role of a putative testicular gonadotropin-releasing hormone (GnRH)-like material was studied in the frog, Rana esculenta. We have investigated (a) changes of mitotic index (MI) of primary spermatogonia (SPG) in GnRH agonist (GnRH-Ag)-treated testes in vitro; (b) changes of androgen concentrations in testes of intact frogs treated with a GnRH antagonist (GnRH-Ant); (c) variations of mitotic index of primary SPG in intact GnRH-Ant-injected animals and in testes incubated with GnRH-Ant; (d) changes of MI in hypophysectomized (PDX) animals treated with hypophysis (PD) homogenate, and hCG alone or in combination with GnRH-Ant; and (e) changes of androgen concentrations in plasma PDX frogs treated with hCG and hCG plus GnRH-Ant. Our results indicate that while GnRH-Ag induced accumulation of primary SPG mitosis, GnRH-Ant inhibited androgen production and natural occurring mitosis accumulation. Therefore, GnRH-Ant may counteract an endogenous peptide working into the testis.
Di Matteo
L
L
Dipartimento di Fisiologia umane e Funzioni Biologiche Integrate F. Bottazzi, I Facoltà di Medicina e Chirurgia, Napoli, Italy.
Minucci
S
S
Fasano
S
S
D'Antonio
M
M
Pierantoni
R
R
Chieffi
G
G
D000728:Androgens / Q000097:blood / Q000378:metabolism; D000818:Animals; D002064:Buserelin / Q000494:pharmacology; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D007016:Hypophysectomy; D008297:Male; D008940:Mitotic Index / Q000187:drug effects; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D011893:Rana esculenta / Q000502:physiology*; D013093:Spermatogonia / Q000166:cytology / Q000187:drug effects; D013737:Testis / Q000187:drug effects / Q000502:physiology*
D000728:Androgens; D006063:Chorionic Gonadotropin; D007987:Gonadotropin-Releasing Hormone; C034511:LHRH, pGlu(1)-Phe(2)-Trp(3,6)-; D002064:Buserelin; D011761:Pyrrolidonecarboxylic Acid