The effects of streptozotocin diabetes and of dietary protein content on the composition and metabolism of testicular lipids.
The effect of streptozotocin-induced diabetes on the fatty acid composition and metabolism in testes of rats on diets varying in protein content has been investigated. The protein content of the diet (40, 20, 5%) had little or no effect on essential fatty acid metabolism during the 2 weeks following injection of streptozotocin, but the 5% diet resulted in a high rate of mortality for diabetic rats. Increased amounts of octadeca-9,12-dienoic (linoleic or 18:2) acid and of eicosa-8,11,14-trienoic (dihomo-gamma-linolenic or 20:3) acid and decreased amounts of eicosa-5,8,11,14-tetraenoic (arachidonic or 20:4) acid were observed in testes of some but not all diabetic compared to pair-fed control rats 2 weeks after injection of streptozotocin. Incorporation of 14C from [14C]18:2 into testicular lipids of these rats was determined 26 hr after intratesticular injection. In some rats there was a greater amount of 14C in eicosa-11,14-dienoic acid (dihomolinoleic acid or 20:2) and 20:3 and less 14C in 20:4 of testes of diabetic than in those of control rats. The suggested impairment in conversion of 18:2 to 20:4 was studied further by using [14C]20:3 as the substrate for intratesticular injection. Four hours after administration of the [14C]polyene there was more 14C in 20:3 and less 14C in 20:4 and in docosa-7,10,13,16-tetraenoic (adrenic or 22:4) acid in testes of diabetic than in those of control rats. The results indicate that in diabetic rats at least one enzyme responsible for the decreased conversion of 18:2 to 20:4 is the delta 5-desaturase.
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D005227:Fatty Acids / Q000378:metabolism*; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013737:Testis / Q000187:drug effects / Q000378:metabolism*; D014280:Triglycerides / Q000378:metabolism
D004044:Dietary Proteins; D005227:Fatty Acids; D010743:Phospholipids; D014280:Triglycerides