Proopiomelanocortin gene expression in the ovary of the frog, Rana esculenta.

The presence of proopionmelanocortin (POMC)-like mRNA has been demonstrated in a variety of extrapituitary tissues including hypothalamus,1 placenta,2 ovary,2 and testis.3 In amphibians, the POMC gene is actively expressed in the pituitary, both in melanotrope cells of the pars intermedia and in corticotrope cells of the pars distalis. 4–6 POMC gene expression in peripheral organs has also been investigated in Rana esculenta,7 indicating that POMC is actually synthetized in the ovary. Previous studies have shown that POMC-derived peptides are involved in local control of ovarian function and display seasonal changes.8,9 The aim of the present work was to develop a competitive reverse transcriptase polymerase chain reaction (RT-PCR) method using a synthetic, deletion mutant of POMC cRNA as an internal standard in order to quantify the amount of POMC mRNA in the ovary of Rana esculenta