Effect of Relaxin on Primary Cultures of Goat Mammary Epithelial Cells

Abstract

Relaxin (RLX) is a peptide hormone produced in the female reproductive tract. However, its site of synthesis, pattern of secretion and structure can vary between species (reviewed by Bryant-Greenwood and Schwabe, 1994). Recent studies have demonstrated synthesis of RLX by the mammary gland in the guinea-pig (Peaker et al.,1989) and its immunolocalisation in the normal, cystic and neoplastic human breast (Mazoujian and Bryant-Greenwood, 1990). These findings imply a possible role for relaxin in influencing the growth of mammary epithelial cells, directly as a mitogen or indirectly through remodelling of the extracellular matrix, in addition to its main functions which are to promote uterine quiescence and softening of the uterine cervix during pregnancy. Indeed, there are reports of RLX stimulating mammary cell growth in vivo in mice (Bani et al., 1986), rats (Wahab and Anderson, 1989) and pigs (Hurley et al., 1991). Furthermore, RLX is reported to promote the growth of mammary cell lines in vitro (Bigazzi et al., 1992). The present study investigated the effect of RLX on proliferation of goat mammary epithelial cells in primary culture.