Victor R. Wheatley

Cutaneous lipogenesis: III. The incorporation of valine carbons into the branched-chain fatty acids of rodent ear skin lipids

Abstract 1. 1. An ear skin-slice incubation technique was employed to study the utilization of valine carbons for fatty acid synthesis in rodent skin. Mouse and rat skin incorporated valine carbons at considerably higher rates than did guinea pig skin. Mouse skin was selected for more detailed studies. 2. 2. The incorporation rate of 14 C into mouse skin fatty acids from dl -[4- 14 C]-valine was twice that from [1- 14 C]isobutyrate. The incorporation rate from dl -[1- 14 C]-valine was only slightly lower than that from [1- 14 C]isobutyrate. 3. 3. The labeling patterns of the saturated fatty acids formed in mouse skin from dl -[4- 14 C]valine and [1- 14 C]isobutyrate were determined. In both cases, the radioactivity was concentrated in even-numbered, iso-branched fatty acids. 4. 4. Labeled isopalmitate, formed from dl -[4- 14 C]valine in mouse skin, was oxidized to remove the terminal branch. Tridecanedioate, a major oxidation product, contained only 24% of the total radioactivity of the isopalmitate.