Very long chain PUFA in murine testicular triglycerides and cholesterol esters

FURLAND NE; MALDONADO EDUARDO NÉSTOR; AVELDAÑO MARTA ISABEL

LIPIDS

American Oil Chemists' Society (AOCS)

Lugar: Champaign IL; Año: 2003 vol. 38 p. 73 - 80

0024-4201

Very long chain (VLC) polyunsaturated fatty acids (PUFA) of the n-6 and the n-3 series are known to occur in mammalian testis. The aim of this work was to characterize further two testicular lipid classes with VLCPUFA, cholesterol esters (CE) and triglycerides (TG) in rat and mouse testis. The VLCPUFA predominating in these lipids were a series of (n-6) pentaenes and tetraenes with 24 to 32 carbons, including small amounts of odd-chain PUFA, 28:5n-6 and 24:5n-6 prevailing in CE and TG, respectively.  Most of the VLCPUFA of TG were concentrated in a small fraction of TG, made up by 1-O-alkyl-2,3 diacylglycerols. This TG subclass was absent altogether from the TG of sexually immature testis. The TG and the EC with VLCPUFA only occurred in testis of adult fertile animals. The proportion of VLCPUFA in total TG and EC was higher in rodents than in other mammals. In the n-6 PUFA rich adult mouse testis, the amounts of testicular triacylglycerols decreased significantly after consumption of fish oil for 2 weeks. Whereas 18:2n-6 was significantly reduced, the amounts of 22:5n-6 and longer n-6 PUFA were less affected in all major testicular lipids including phosphatidyl- choline and –ethanolamine, where it was unchanged. The 1-O-alkyl-2,3 diacylglycerols and their n-6 VLCPUFA were virtually unaffected by the diet. The VLCPUFA-containing molecular species of EC and TG may represent a form of storage of cholesterol and polyenoic fatty acids required to sustain spermatogenesis. Via chain-shortening, VLCPUFA stored in the neutral lipids may serve as precursors of the major C22 PUFA typical of cell membrane glycerophospholipids, protecting testicular cells against shifts in fatty acid composition induced by dietary changes.