The development of ideas on the role of glucose in regulating milk secretion

Abstract

The author has reviewed the development of theories, over the last century, on the role of glucose in mammary metabolism, focusing on three overlapping issues, via. the extent of glucose utilization by mammary tissue, the synthesis of lactose, and the way in which glucose supply controls secretion of the aqueous phase of milk. In the first half of the century, deficiencies in technique produced several misleading results, and later progress resulted largely from methodological advances. Methodology has also been important in shaping research programmes, as is evident in the current emphasis on techniques of molecular biology. However, the review indicates the importance of employing a combination of experimental approaches, including whole-animal studies. Through the adoption of such approaches, it is now appreciated that glucose plays a key role in regulating lactation. It is suggested that developments over the last 30 years, which have led to formulation of an apparently resilient theory of milk secretion, conform to the notion of a 'progressive research programme' built on a 'positive heuristic', as proposed by the philosopher of science, I. Lakatos.