In vitro release of luteinizing hormone-releasing hormone (LHRH) from rat mediobasal hypothalamus: effects of potassium, calcium and dopamine.
A suitable preparation to study the effect of dopamine (DA) on in vitro LHRH secretion is presented. Enzymatic degradation of LHRH in the incubation medium is completely inhibited by bacitracin (2 X 10(-5) M). Ahigh potassium concentration (56mM) induces an increase in LHRH release from entire pieces of mediobasal hypothalamus (MBH), but not from a synaptosomal pellet; this release is inhibited when calcium is omitted. The depolarization-induced LHRH in the MBH. In contrast, DA (10(-6)M) is not effective in vitro on MBH from ovariectomized rats but induces a fast release of LHRH from MBH of normal male and estradiol-pretreated ovariectomized rats. The preparation presented here appears to be of great interest in investigating amine-steroid-LHRH interactions at the cellular level.
D000818:Animals; D001414:Bacitracin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D007033:Hypothalamus, Middle / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D010053:Ovary / Q000502:physiology; D011188:Potassium / Q000494:pharmacology; D051381:Rats
D001414:Bacitracin; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D011188:Potassium; D002118:Calcium; D004298:Dopamine