Ovarian expression of melatonin Mel(1a) receptor mRNA during mouse development

Melatonin, secreted by the pineal gland, is involved in the regulation of m any physiological functions of various species of animals. In the present s tudy, the expression of gene for melatonin Mel(1a) receptor (MelR) was eval uated in the ovary, hypothalamus, and pituitary according to the developmen tal stages in female mice. Semiquantitative reverse-transcription polymeras e chain reaction (RT-PCR) and in situ PCR techniques were applied. Accordin g to the developmental stages, gene for MelR was differently expressed on o vary, hypothalamus, and pituitary. MelR gene was first expressed on pituita ry prior to the expression in hypothalamus and ovary. Ovarian MelR gene sta rted to express at birth. Unlike hypothalamic expression of MelR gene which was identified after birth, in pituitary, it was expressed at 16 days post coitum. In the ovary, the expression signal of MelR gene was identified on granulosa cells. However, the signal was not detected in the theca cells. It was weak in the primordial and atretic follicles. Taken together, it can be considered that melatonin has a pivotal role in the folliculogenesis. M ol. Reprod. Dev. 59:126-132, 2001. (C) 2001 Wiley-Liss, Inc.