Relaxin-like factor gene is highly expressed in the bovine ovary of the cycle and pregnancy: sequence and messenger ribonucleic acid analysis.

Relaxin-like factor (RLF) is a new member of the insulin/insulin-like growth factor family of hormones and growth factors, which appears to be predominantly expressed in the Leydig cells of the testis. An analysis of male and female bovine tissues indicated that in the cow the RLF gene is also highly expressed in the female, mainly in the follicular theca interna and in the corpus luteum, with a pattern of gene expression very similar to that for the related peptide relaxin in other species. Sequence analysis of bovine testicular and luteal RLF and cDNA shows that the same gene is expressed in both male and female gonads. Because the bovine RLF sequence, like those from pigs, humans, and mice, retains, the putative receptor binding motif described for relaxin, it seems plausible that RLF might functionally substitute for relaxin in the cow, in which the latter peptide appears not to be significantly expressed.