Direct effects of the pineal hormone melatonin on testosterone synthesis of Leydig cells in Djungarian hamsters (Phodopus sungorus) in vitro.
Leydig cells of adult Djungarian hamsters, stimulated with luteinizing hormone (LH), were co-incubated with melatonin at various concentrations in a primary culture system. Testosterone secretion was only affected by melatonin when cells were stimulated with LH. Maximal suppression was observed at low doses of LH (0.5 ng/ml). These effects are at least partially mediated through the adenylate cyclase system, since melatonin was able to reduce forskolin-stimulated testosterone secretion. These results indicate that the time between pulses of LH can be considered to be most highly effective for tonic melatonin actions.
Niedziela
M
M
Institute of Reproductive Medicine of the University, Münster, Germany.
Lerchl
A
A
Nieschlag
E
E
D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007985:Leydig Cells / Q000187:drug effects*; D007986:Luteinizing Hormone / Q000494:pharmacology; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D013739:Testosterone / Q000097:blood* / Q000378:metabolism*
D005576:Colforsin; D013739:Testosterone; D007986:Luteinizing Hormone; D008550:Melatonin