Mary P. Carpenter

The lipid composition of maturing rat testis the effect of α-tocopherol

Abstract 1. 1. Quantitative studies of lipid components of testes of experimental rats, deprived of α-tocopherol, and controls, during maturation, maintenance and aging of the germinal epithelium are reported. 2. 2. Although the initial biochemical lesion produced by α-tocopherol occurs in the prepubertal rat, no marked changes are seen between testes of control and experimentals until the testes are fully differentiated. 3. 3. A decrease in the amount of lipid in the experimental rat, reduction in the content of phospholipid, but no changes in the proportion of phospholipid classes or unsaturation are seen. 4. 4. In experimental testes, the amounts of C16:0 and C22:5ω6, decrease in the neutral and phospholipid fractions and ω3 fatty acids increase in the neutral lipid 5. 5. Intermediates in the biosynthetic pathway for C22:5ω6 do not accumulate; the possibility that the retroconversion of C22:5 contributes to the constancy of C20:4ω6 is considered. 6. 6. That the alternate pathway for C20:4 may function in immature testis is indicated by the presence of C20:2ω6. Only the neutral lipid contains significant amounts of C24:4ω6 and 24:5ω6. 7. 7. A comparison of testicular lipid changes resulting from other treatments indicates those induced by α-tocopherol deficiency are unique. That α-tocopherol may function as a regulator of the metabolism of linoleate-derived polyenoic fatty acids is suggested.

The lipid composition of the prepubertal and adult rat testis

Abstract A quantitative study of the lipid components of maturing rat testes which includes data on the fatty acid components of individual phosphatides, triglycerides and cholesteryl esters has been made. Testicular lipids of prepubertal and adult rats have been isolated and separated into individual neutral lipid and phosphatide classes by silicic acid column chromatography. The lipid representing 2.2% of the tissue wet weight was about 80% phosphatide and 20% neutral lipid. Phospholipid distribution was as follows: phosphatidyl choline, 47.5%; phosphatidyl ethanolamine, 26.2%; phosphatidyl serine, 7.2%; phosphatidyl inositol, 2.3%; and sphingomyelin, 6%. Plasmalogens were found primarily in the phosphatidyl ethanolamine fraction. Free cholesterol, about 95% of total cholesterol, and triglyceride were the predominant classes found in the neutral lipid fraction; monoglyceride, trace amounts of diglyceride and other components were also detected. No conspicuous differences in the relative distributions of the lipid classes were observed between the immature and adult animal. The fatty acid composition of each of the isolated lipid classes was determined by gas-liquid chromatography. Comparable fractions of the neutral lipids and of phospholipid classes of both young and mature testes had similar fatty acid contents. Major fatty acids of the triglyceride fraction were palmitic, oleic, and docosapentaenoic; unsaturation increased in the older animal. About half of the fatty acids of the phosphatides were unsaturated; palmitic, stearic, oleic, arachidonic and docosapentaenoic acids represented most of the fatty acids found, but their relative distributions varied in individual phosphatides. β-Position fatty acids of phosphatidyl choline were predominantly oleic and arachidonic in the prepubertal animal but the concentration of docosapentaenoic in the adult increased to equal that of arachidonic. A similar relative distribution of unsaturated fatty acids was found in the phosphatidyl ethanolamine fractions, but large amounts of palmitic and stearic were also present. A marked increase in the concentration of docosapentaenoic acid was found in the triglyceride fraction as well as in individual phosphatide classes of the adult testes.

Creatine-phosphate utilization by muscle extracts of rabbits on vit. E-deficient diets.

Summary A method for determination of the transfer of phosphate from creatine-phosphate to the hexosemonophosphates is described. It has been found that this transference is decreased in the muscle of rabbits fed tocopherol-deficient diets at a time when phosphoglucomutase activity and glycolysis are normal. The decrease in transference is not corrected by addition of ATP. ATP added at concentrations above 0.004 M inhibits phosphoglucomutase.