Pyruvate dehydrogenase, the citrate condensing enzyme and the utilization of 14 C-labeled lactate, pyruvate and alanine by slices of lactating mammary gland and adenocarcinoma of mouse mammary gland.

Abstract

SummaryThe utilization of 14C-labeled lactate, pyruvate and alanine by tissue slices of lactating mouse mammary gland and adenocarcinoma of the mouse mammary gland was investigated. In the absence of glucose, rates of 14CO2 formation and fatty acid synthesis from these substrates in the mammary adenocarcinoma were considerably lower than those in the lactating mammary gland, regardless of the position of the labeled carbon. In the lactating mammary gland, addition of glucose caused a considerable decline in 14CO2 formation from the second and third carbons of lactate, pyruvate and alanine, while it significantly stimulated their incorporation into fatty acids. Glucose also stimulated 14CO2 formation from the first carbon of these substrates. In the mammary adenocarcinoma, however, 14CO2 formation from the first carbon of lactate and pyruvate decreased upon glucose addition, while that from the second and third carbons was almost unaffected. The incorporation into fatty acids of the second and third carbon...