The metabolism of (1-14C) stearic acid in rat testicular tissue.
(1) The metabolism of stearic acid was studied in vivo following intratesticular injection of [1-14C] stearate. Soon after injection 14C activity was found mainly in the free fatty acid pool. This was followed at later time periods by transfer of label primarily to the phosphatide pool. During each time period significant amounts of label were recovered at 14CO2. (2) Analysis of 14C-labeled fatty acids from the injected testes demonstrated an initial rapid rate of oxidation and desaturation of [1-14C] stearate followed by a slower steady state rate. It was concluded that the initial rate was due to the rapid turnover of the highly labeled free fatty acid pool followed by a much slower rate as [14C] stearate was esterified to the more metabolically stable phospholipids. Elongation of the labeled stearic or its desaturated derivative was not observed. (3) The rate of desaturation in vitro of stearic acid was measured in microsomal preparations from rat testes and found to be 12.0 +/- 0.5 pmol/min/mg compared to the estimated in vivo value of 22 pmol/min/mg and the value of 390 pmol/min/mg for hepatic microsomal desaturase.
D000818:Animals; D008297:Male; D008861:Microsomes / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism; D009928:Organ Specificity; D051381:Rats