Effects of gonadotrophin-releasing hormone on testosterone secretion by fetal and neonatal rat testes in vitro.
Testosterone production by fetal (20.5 days) and neonatal (1-day-old) rat testes was measured to study the possible direct effect of gonadotrophin-releasing hormone (GnRH) on steroidogenesis in early development. Single gonads were incubated in the presence and absence of GnRH (10(-10) to 10(-6) M) or agonistic analogues (10(-11) to 10(-7) M). For comparison, some testes were incubated with ovine luteinizing hormone (0.001-0.01 microgram oLH1 NIH-LH-S20/ml of medium TC199. No clear evidence of stimulation by an agonist (10(-7) M) was seen with fetal testes, but the lowest concentration (10(-11) M) gave results suggestive of an inhibitory action. Similar experiments with neonatal testes showed stimulation. With the highest concentration of GnRH or agonist the amounts of testosterone produced were about 2-3-fold greater than from control testes. Greater quantities of testosterone were found with testes exposed to LH. Hourly sampling in one experiment showed that significant stimulation of testosterone secretion had occurred within the first hour with GnRH (10(-6) M). It was concluded that fetal-neonatal rat Leydig cells are responsive to GnRH.
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005333:Fetus / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D010906:Pituitary Hormone-Releasing Hormones / Q000494:pharmacology*; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000032:analysis; D011966:Receptors, LHRH; D013737:Testis / Q000187:drug effects / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism*
D010906:Pituitary Hormone-Releasing Hormones; D011956:Receptors, Cell Surface; D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; C010661:surfagon