Uneven distribution of ceramides, sphingomyelins and glycerophospholipids between heads and tails of rat spermatozoa

ORESTI, G.M. (CORRESPONDING AUTHOR); LUQUEZ, J.M.; FURLAND, N.E.; AVELDAÑO, M.I.

LIPIDS

SPRINGER HEIDELBERG

Lugar: Berlin :b Springer : American Oil Chemists' Society; Año: 2011 vol. 46 p. 1081 - 1090

0024-4201

Previous work showed that rat germ cells and spermatozoa contain ceramides and sphingomyelins with high proportions of nonhydroxy and 2-hydroxy (2-OH) polyunsaturated fatty acids (PUFA) with very long chains (VLCPUFA). The aim of this study was to assess how these lipids are distributed between head and tail of mature spermatozoa in comparison with other membrane lipid classes. In addition to quantitative differences due to the fact that these gametes have a long, voluminous tail and a minute head, several compositional dissimilarities emerged between these two regions. In the head, the total cholesterol / total phospholipid ratio, the choline / ethanolamine glycerophospholipid (ChoGpl / EtnGpl) ratio, and the proportion of plasmalogens within these two classes, were much larger in the head than in the tail. Whereas EtnGpl was rich in 22:5n-6 in both regions, ChoGpl had plenty of 22:4n-9, especially in heads. An important proportion of the head EtnGpl- 22:5n-6 and ChoGpl 22:4n-9 was in plasmenyl- (rather than in phosphatidyl-) subclasses. The heads concentrated all of the sphingomyelin species with nonhydroxy- and 2-OH VLCPUFA, and the tails most of the saturated fatty acids, that are present in total sperm sphingomyelin. Unexpectedly, virtually all of the abundant spermatozoal ceramides, predominantly made up by species with 2-OH VLCPUFA, was located to the tail. The fact that intact rat spermatozoa constitutively have much more VLCPUFA-containing ceramide than sphingomyelin is explained by the present findings, since the former are mostly lipids of the large tail while the latter mostly collect in the small head. DOI 10.1007/s11745-011-3601-x