Genetic determination of coat color affects testicular steroidogenesis in the Mustela vison.

Coat color genes in mammals are known to be developmental genes with wide pleiotropic effects. The present study was undertaken to study testicular steroidogenesis in American Mink (Mustela vison) of various coat color phenotypes. No differences in testicular steroid levels were observed between fertile and infertile mink with the standard phenotype and genotype (BB jj MM PP). Mink with the opaline phenotype and genotype (bb mm pp), were found to have in their testes, 20-40% higher levels of progesterone, five times higher levels of 17-hydroxyprogesterone, and eight times higher levels of testosterone, than the corresponding values in other mink. No other differences were observed among the different types of mink. Since the genotype of the opaline mink differs from the other mink studied, only in their combination at the pastel (b) and moyle (m) loci, their bb mm genotype could be assumed to be responsible for the increase in testicular steroids.