Nonequilibration of Acetyl Units from Fatty Acids and Glucose in Mammary Glands of Lactating Mice

• Published in: Journal of dairy science 1975-12, Vol.58 (12), p.1799-1802
• Main Authors: Rao, G. Ananda, Abraham, S.
• Format: Article
• Language: English
• Subjects: Acetates - metabolism; Animals; Carbon Dioxide - metabolism; Fatty Acids - metabolism; Female; Glucose - metabolism; Lactation; Lipids - biosynthesis; Mammary Glands, Animal - metabolism; Mice; Mice, Inbred C3H; Oxidation-Reduction; Pregnancy; Pyruvates - metabolism; Triglycerides - biosynthesis
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(75)84789-8

Lipid synthesis by lactating mouse mammary gland slices from [1-carbon-14] propionate, [1-carbon-14] valerate, and [1-carbon-14] heptanoate, in the presence of glucose and from [uniformly labeled carbon-14] glucose in the presence of propionate, valerate, and heptanoate was studied. Regardless of the labeled substrate, almost all of the radioactivity incorporated in the total lipid fraction was in triglycerides. In experiments with labeled glucose and either the propionic. the valeric, or the heptylic acid, the carbon-14 fatty acids in triglycerides were almost exclusively composed of even-chain fatty acids. When the substrate was either [1-carbon-14] propionate, [1-carbon-14] valerate, or [1-carbon-14] heptanoate, in the presence of glucose, the pattern changed to one in which a larger proportion of the radioactivity was in the odd-chain fatty acids. These findings suggest that in mouse mammary gland, acetyl units produced via β-oxidation of fatty acids may not equilibrate with those formed from oxidation of pyruvate which is derived from glucose.