Some Recent Advances in the Knowledge of the Physiology of Milk Secretion

Abstract

When it became established that the mammary gland synthesized milk rather than filtered milk out of the blood it became obvious that the blood was the source of the milk constituent precursors. To get an idea as to how milk is synthesized it also became obvious that analysis of the blood to ascertain the constituents used by the mammary gland is a logical approach to the problem. The early work of this nature was that of the comparison of the jugular venous blood and the mammary venous blood based on the assumption that any differences observed would be due to mammary gland metabolism. It has, however, been shown that the type of metabolism in the head, which the jugular blood drains, is different from that of the mammary gland and that, therefore, the conclusions drawn were erroneous. The more recent approach has been a study of arteriovenous differences.