ヒト睾丸の脂質ならびに脂肪酸構成に関する研究

Abstract

Twenty-five testes from 14 men aged 20 to 70 were submitted to the thin-layer and gas chromatographic analysis of the total lipid content, phospholipid centent, phospholipids composition, neutral lipids composition, fatty acid composition of each fraction of phospholipids and neutral lipids. The total lipid amount in the human testis was 2.2 % of the weight of the testis, and phospholipid occupied approximately 40 % of it (Table 1). Phospholipid was composed of phosphatidyl choline 44.3 %, phosphatidyl ethanolamine 26.1 %, phosphatidly inositol 10.7 %, sphingomyelin 9.0 %, lysophosphatidyl choline 2.1 %, phosphatidyl serine 1.7 %, phosphatidic acid and cardiolipin 3.8 % (Fig. 1, 2 and Table 2). Neutral lipid was composed mainly of free cholesterol and cholesterol ester. followed by free fatty acid and small amount of monoglyceride and diglyceride (Fig. 3 and Table 3). The total fatty acid was composed of the saturated fatty acid (45.5 %) and the unsaturated (54.2 %). 65.5 % of the latter was polyunsaturated. Main fatty acid were palmitic and stearic acid for the saturated fatty acids, oleic and palmitoleic acid for the monounsaturated, and the long chain polyunsaturated fatty acids such as docosahexaenoic acid, arachidonic acid, eicosatrienoic acid for the polyunsaturated (Table 4). Out of phospholipid fractions, phosphatidyl choline, phosphatidyl ethanolamine, phosphatidylinositol and sphingomyelin were submitted to analysis of their constituent fatty acids. Generally, each fraction of phospholipid showed high percentage of the saturated fatty acids and low percentage of the unsaturated except phosphatidyl ethanolamine. Phosphatidyl ethanolamine was found to be rich in the polyunsaturated fatty acids such as docosahexaenoic acid and others. As to neutral lipids, the constituent fatty acids were investigated on cholesterol ester. Free fatty acid, triglyceride. diglyceride and monoglyceride. Each fraction of the neutral lipid contained the unsaturated fatty acids more than the saturated. This was the striking difference from the phospholipid fractions. There was only small amount of palmitic acid in the saturated fatty acid and large amount of oleic acid in the unsaturated. Docosahexaenoic acid was abundant except in the free fatty acid fraction, especially rich in triglyceride (Table 4). The role of C22-polyunsaturated fatty acid in the differentiation and development of the seminiferous tubules had been formerly elucidated in the experimental animals by that docosahexaenoic acid is the important fatty acid related to spermatogenesis.