Lipid content of sheep ovarian follicles in culture.

A detailed examination was made of the lipid content of sheep ovarian follicles maintained in organ culture, and of the effect on this of human chorionic gonadotrophin. Lipid classes were isolated by thin-layer chromatography and the fatty acid composition determined by gas chromatographic analysis. The mean total lipid content of isolated follicles, 4-6 mm in diameter, after 18 h in organ culture was 43.1 nmol/mg wet weight tissue. Five major lipid fractions were detected, namely phospholipids (21.0 nmol/mg), cholesterol (14.5 nmol/mg), triglycerides (3.1 nmol/mg), free fatty acids (1.1 nmol/mg), and cholesteryl esters (3.4 nmol/mg). The phospholipid fraction was distinctive in that it contained a large percentage of sphingomyelin (28.0%). Other phospholipids present were phosphatidyl choline (42.0%), phosphatidyl inositol (6.9%), phosphatidyl serine (6.1%), and phosphatidyl ethanolamine and phosphatidic acid (16.9%). Each lipid fraction had a characteristic fatty acid profile which was rich in the content of unsaturated fatty acids. Inclusion of human chorionic gonadotrophin (20 i.u. ml-1) in the culture medium caused no discernable effects on the follicular content of lipids nor on the fatty acid composition of individual lipid fractions.