CHANGES IN RAT SPERMATOZOA LIPIDS AND FATTY ACIDS DURING EPIDIDYMAL MATURATION

ZANETTI S; MONCLUS M A; AVELDAÑO M; FORNES M W

Rosario, Santa Fé

Congreso; XLII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2006

SAIB

CHANGES IN RAT SPERMATOZOA LIPIDS AND FATTY ACIDS DURING EPIDIDYMAL MATURATION Zanetti SR; Monclus MA; Aveldaño MI and Fornés MW IHEM, CONICET-UNC, 5500 Mendoza e INIBIBB, CONICET-UNS, 8000 Bahía Blanca , Argentina. During their epididymal transit, spermatozoa undergo a series of maturational changes that render them potentially capable of fertilization. Here we focused on the changes undergone by major lipid classes and fatty acids. The content of neutral lipids including cholesterol (Ch) as well as of phospholipids (PL) decreased with epididymal maturation. The Ch/PL ratio, and within PL the choline/ethanolamine glyceroPL (CGP, EGP) ratio, increased significantly from caput to cauda epididymis. The most pronounced change observed in total glyceroPL fatty acids was an increase in the proportion of 22:4n-9. The percentage of this fatty acid increased about 8-fold in the CGP with sperm maturation, whereas the EGP contained 22:5n-6 as their major fatty acid at both stages. Interestingly, mature sperm 1-O-alkyl-2,3-diacylglycerols also had 22:4n-9. The content per cell of sphingomyelin (SM) and ceramide (Cer), also changed with maturation, increasing the Cer/SM ratio in sperm from cauda with respect to caput. Both these lipids contained normal and 2-hydroxylated VLCPUFA, such as 28:4n-6 and 2-OH-28:4n-6. The marked alterations spermatozoa undergo during their epididymal transit in lipid and fatty acid profile may lead to changes in the biophysical properties that are optimal in determining the physiological functions of these gametes.