Melatonin receptor mRNA expression in human granulosa cells

We have shown that the melatonin receptor agonist, 2-[I-125] iodomelatonin, binds to high-affinity guanine nucleotide-sensitive sites on human granulo sa (HC) cell membranes. In order to confirm the presence of melatonin recep tors in HG cells, we have now used a reverse transcriptase-polymerase chain reaction (RT-PCR) procedure to examine receptor subtype expression. RT-PCR studies revealed the presence of the mt(1) (Me-1a) melatonin receptor subt ype in ten single or pooled HG cell samples which were obtained from 14 pat ients. In contrast, expression of MT2 ( Mel(1b)) mRNA was observed in only two of these HG samples. DNA sequencing of the mt(1) PCR product confirmed its identity with the reported human mt, melatonin receptor. The expression of mt, and MT2 receptor mRNA in HG cells and the reported presence: of mel atonin in human follicular fluid indicate a potentially important role for this hormone in regulating human ovarian and reproductive function. (C) 199 9 Elsevier Science Ireland Ltd. All rights reserved.