LOCAL RELAXIN BIOSYNTHESIS IN THE OVARY AND UTERUS THROUGH THE ESTROUS-CYCLE AND EARLY-PREGNANCY IN THE FEMALE MARMOSET MONKEY (CALLITHRIX-JACCHUS)

The pattern of peripheral serum concentration for the peptide hormone relaxin in women points to the possibility of an interesting paracrine function in the cycle and early pregnancy. In order to investigate th is physiology in detail, it was decided to examine local relaxin biosy nthesis in an established primate model for human female reproductive function, the marmoset monkey (Callithrix jacchus). In this initial st udy relaxin biosynthesis was assessed using a combination of molecular and immunological techniques through the oestrous cycle in the marmos et monkey. The nucleotide sequence of the full-length relaxin gene tra nscript was cloned from the marmoset ovary and found to be closely hom ologous to that of the human H2 relaxin. Using gene specific probes de rived from this sequence, RNase protection assays, reverse transcripti on-polymerase chain reaction (RT-PCR) assays and in-situ hybridization , showed relaxin gene expression within the ovary in theca cells and c orpora lutea in the oestrous cycle, increasing in early pregnancy. Rel axin gene expression was also identified at a low level in the uterus and placenta, and at a higher level in the prostate in the male marmos et monkey. Using two different relaxin-specific antisera, relaxin-like immunoreactivity was observed in the ovary with a pattern of distribu tion coincident with that obtained by in-situ hybridization. Immunorea ctivity was also found in the nonpregnant uterus, within the endometri al epithelium of the late proliferative phase and increasing within th e glands through the secretory phase. Taken together, the pattern of r elaxin peptide and mRNA expression show there is the basis for local r elaxin physiology within the ovarian follicle and corpus luteum, and w ithin the uterus during the oestrous cycle in this new world monkey.