Identification of fatty acid esters of pregnenolone and allopregnanolone from bovine corpora lutea.

The lipoidal derivatives of steroids present in bovine corpora lutea have been identified and quantified. Nonpolar steroid derivatives were extracted from the tissue with a mixture of chloroform and methanol. The extract was subjected to column and high performance liquid chromatography in order to remove phospholipids, cholesterol, triglycerides, cholesteryl esters, and unesterified steroids. A portion of the purified nonpolar material was subjected to methanolysis. By gas-liquid chromatographic analysis, the products were shown to consist of the steroids 3 beta-hydroxy-5 alpha-pregnan-20-one (80%) and pregnenolone (20%), and the methyl esters of palmitic (34%), stearic (27%), oleic (22%), linoleic (7%), arachidonic (7%), palmitoleic (3%), and eicosatrienoic (1%) acids. Mass spectrometric analysis of the intact lipoidal derivatives and of their methoximes confirmed the presence of seven esters of allopregnanolone and pregnenolone: allopregnanolone palmitate, pregnenolone palmitate, allopregnanolone stearate, allopregnanolone oleate, allopregnanolone linoleate, allopregnanolone eicosatrienoate, and pregnenolone arachidonate. The mass spectral data suggested that four other esters were also present: pregnenolone stearate, pregnenolone oleate, pregnenolone linoleate, and allopregnanolone arachidonate.