The lipid composition of the adrenals of non‐pregnant, pregnant and foetal sheep

Abstract

Lipids were isolated from the adrenals of non-pregnant, pregnant and foetal sheep (ca 30 days pre-parturition). The lipid content of the adrenals from the pregnant sheep was higher than that of the other groups, and most of this was accounted for by triacylglycerols. Little difference was observed in the fatty acid compositions of the various lipid classes between the pregnant and non-pregnant animals. All the lipids of the foetal adrenals contained substantial amounts of the 20: 3(n-9) fatty acid, which is often associated with essential fatty acid deficiency, but only the cholesterol ester fraction contained a higher level of polyunsaturated fatty acids than was present in the adult groups. The adrenals of the pregnant sheep contained significant levels of glycerolether diesters and neutral plasmalogens, which were fully characterised, and four unknown components that were tentatively identified as steroidal esters. These components were present at barely detectable levels in the adrenals of non-pregnant sheep. The triacylglycerols, glycerolether diesters and phosphatidylcholines from each group were, where possible, subjected to stereospecific analysis. The triacylglycerols were distinctive and resembled those of plasma and lymph in structure. The results are discussed in terms of a putative direct role for cholesterol esters in corticosteroidogenesis.