OCCURRENCE OF AN OVARIAN OPIOID SYSTEM IN OVIPAROUS VERTEBRATES - PROOPIOMELANOCORTIN MESSENGER-RNA EXPRESSION IN THE OVARY OF THE GREEN WATER FROG, RANA-ESCULENTA

The aim of the present study was to investigate whether the proopiomel anocortin (POMC) gene is expressed in the ovary of Rana esculenta. Usi ng a homologous probe, the presence of POMC mRNA could nor be detected by Northern blot analysis in the ovary, while a positive signal wa fo und in the pituitary gland. In contrast, after amplification of ovaria n mRNA by the PCR technique, an intense signal of 480 bp was detected by Southern blotting. indicating that POMC is actually synthesised in rile ovary.