The Metabolism of Serine-3-C14 by the Lactating Sheep Mammary Gland

Abstract

Eight hours after serine-3-C14 was placed into the gland cisterns of lactating ewes, various components of milk and mammary tissue were assayed for radioactivity. In 2 experiments 87 and 94% of the serine was metabolized by the gland. Of the recovered C14, 98 and 99% was located in milk and glandular proteins. The specific activity of milk proteins indicates the formation of casein and lactalbumin from the same amino acid pool. A small but significant quantity of C14 was isolated in phospholipids.