Gene expression of the melatonin receptor in human granulosa cells

Abstract

Recent findings have shown that melatonin emerges as an effective oral contraceptive and that it appears to be a novel alternative for fertility control in humans because anovulation is achieved without the many negative side-effects associated with estrogencontaining oral contraceptives. In view of the putative presence of melatonin receptors in the ovary, as determined y binding studies, and the high concentration of melatonin in follicular fluid in comparison to plasma, a direct inhibitory effect on ovarian function is supported. The mechanism underlying anovulation by melatonin is unknown but the demonstration of melatonin receptors in human granulosa cells points to an autocrine regulatory role for melatonin. Human granulosa cells were aspirated from preovulatory follicles from women undergoing in vitro fertilization. After isolation of total cytosolic ribonucleic acid (RNA) from the cultured cells, they were reverse-transcribed to first strand complementary deoxyribonucleic acid (cDNA) and amplified with a set of primers derived from the human melatonin 1b (Mel1b) receptor cDNA clone. Preliminary studies show that the polymerase chain reaction product corresponded to the expected size of the Mel1b receptor. This finding provides evidence for the gene expression of the Mel1b receptor in human granulosa cells and suggests that melatonin is a regulator in the ovary.