Differentiation-related changes in lipids with very long chain polyenoic fatty acids in germ cells

ORESTI GM; REYES JG; FURLAND NE; AVELDAÑO MI

Tucumán

Congreso; XLV Reunión Nacional de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2009

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Pachytene spermatocytes, round spermatids, and epididymal spermatozoa were isolated to determine differentiation-related changes in their sphingomyelins (SM) and ceramides (Cer) very long chain polyenes (VLCPUFA). The gametes were also examined to study the topological distribution of these lipids. Non-hydroxy VLCPUFA predominated in the SM and Cer of spermatocytes, whereas 2-OH VLCPUFA prevailed in the SM and Cer of spermatids and spermatozoa. During the progression spermatocytes ?¨ spermatids ?¨ spermatoza,  28:4n-6 decreased, though less than did 30:5n-6, thereby becoming the major VLCPUFA. Concomitantly, 2-OH 30:5n-6 increased, though  more than did 2-OH 28:4n-6, thus becoming the main 2-OH VLCPUFA in both lipids. Spermatozoa had SM with 28:4n-6 and 2-OH VLCPUFA, mostly located to the head, and Cer with 2-OH VLCPUFA, mostly situated in the tail. These lipids and fatty acids, in similar proportions, were the same that appeared in round spermatids. Thus, SM and Cer with non-hydroxy and 2-OH VLCPUFA are generated in spermatogenic cells within seminiferous tubules. Both lipids accompany the gametes almost without changes from their last modification, in round spermatids, to their almost complete maturity after their passage through the epididymal epithelium. The possible functions and properties of the unusual SM and Cer of rat spermatozoa will be the aim of future studies.