Urea Formation by the Lactating Goat Mammary Gland

Abstract

NEARLY thirty years ago Graham et al.¹ suggested, on the basis of arteriovenous difference measurements, that urea was produced by the lactating goat mammary gland. This view gained credence with the discovery of arginase in lactating mammary tissue and in a review article in 1949 Folley² considered it probable that the deamination of amino-acids (with related urea production) was an important source of the carbohydrate required for milk secretion. Later results of arteriovenous difference measurements and perfusion experiments in the cow, together with the demonstration that amino-acids absorbed by the gland are used for milk protein formation, however, appeared to invalidate this view (see Barry³).