Studies of the Carbohydrate Metabolism of Mammary Gland Tissue in Vitro. I. Production and Utilization of Various Carbohydrate Substances

Abstract

By the use of perfusion technique and incubation of mammary tissue slices and breis, the formation of lactose from glycogen, glucose, lactic acid, pyruvic acid, citric acid and maltose was studied. By perfusing the bovine mammary glands for 4-5 hrs. with blood of high glucose content, the glycogen content of the mammary tissue was increased by an avg. of 206.6 mg. %. It was demonstrated that upon incubation of tissue slices lactose was formed from this glycogen. Lactose was also formed by incubated tissue slices from added glucose, maltose, glucose and lactic acid, and glycogen. Lactose formation did not occur in incubated tissue breis when these substances were added presumably because of cellular destruction in the breis. Lactic acid was formed in incubating tissue from added glucose, maltose, glycogen, pyruvic acid and citric acid. Variations in pH of the incubations between 6.6 and 7.2 had no effect. It is pointed out that while stored glycogen in the mammary tissue is converted into lactose that such does not necessarily indicate that lactose is formed only from glycogen.