title: The dynamics of the steroidogenic response of perfused Xenopus testis explants to gonadotropins.
abstract: The dynamics of androgen production by perfused Xenopus testis explants has been investigated under various gonadotropic stimulations. Androgens were measured in perfusate by radioimmunoassay. The behavior of hormones in the perfusion system was assessed. Pieces of testis were capable of producing androgens after more than 20 hr in perifusion. Amplitude and duration of the response to a gonadotropic stimulation were the same 3 and 10 hr after the beginning of the experiment. After stimulation by pituitary extract, hCG, or carp GTH, there was a rapid tenfold increase in androgen secretion with a maximum after 1.5 hr and then a slow decrease to a basal line level. A typical log dose-response curve was obtained with hCG and cGTH. After 6 hr continuous stimulation by pituitary extract, steroid secretion increased and reached a plateau 4 hr later. The decrease occurred only after the end of stimulation. The same amount of pituitary extract injected into the column at the rate of 4 min stimulations every hr gave the same type of response. As far as is known, the present data are the first on perifusion systems on the testes of lower vertebrates.
mesh_terms: D000728:Androgens / Q000096:biosynthesis* / Q000378:metabolism; D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006062:Gonadotropins / Q000494:pharmacology*; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D010477:Perfusion; D013737:Testis / Q000187:drug effects / Q000378:metabolism*; D014982:Xenopus laevis / Q000378:metabolism*
chemical_list: D000728:Androgens; D006063:Chorionic Gonadotropin; D006062:Gonadotropins