The presence of the milk protein, α-lactalbumin and its mRNA in the rat epididymis

Abstract

α-Lactalbumin, a modifier protein that changes the substrate specificity of galactosyltransferase, to promote the synthesis of lactose, is found in the mammary glands of lactating mammals and in milk. Molecules similar to mammary gland α-lactalbumin but distinct in their modifier activity have been found in rat epididymal fluid. We report here, using a rat mammary gland α-lactalbumin cDNA clone as a hybridization probe, RNA sequences homologous to α-lactalbumin mRNA were detected in total RNA from the rat epididymis. This finding suggests that α-lactalbumin or similar molecules, in adddition to regulating lactose synthesis in the mammary gland, may have other important functions in mammalian reproduction.