Testosterone and soluble factors from sertoli cells stimulate sphingolipid synthesis in germ cells

SANTIAGO VALTIERRA, F.X.; AVELDAÑO, M.I.; ORESTI, G.M.

Congreso; LIV Annual meeting of the Society of Biochemistry & Molecular Biology (SAIB); 2018

Germ cells from male rodents require membrane sphingomyelins (SM) and ceramides (Cer) with very long chain polyunsaturated fatty acids (VLCPUFA), in non-hydroxylated (n-V) and 2-hydroxylated (h-V) versions, for normal spermatogenesis. We have previously shown that spermatogenic cells isolated from seminiferous tubules of adult rats, in culture, are able to synthesize de novo the sphingolipids (SL) Cer, SM, and Glucosyl-Cer (GlcCer). Here, we evaluated the effect on such biosynthesis of supplementing the cultures with testosterone (T), with the supernatant medium recovered from primary Sertoli cell cultures (SMSC), and with both. Germ cells from adult rats were isolated and cultured in a medium containing [3H]palmitate as SL precursor. Label from this marker was incorporated into species of Cer and SM that contain saturated fatty acids (S), monoenoic fatty acids (M) and also in those containing n-V and h-V. In germ cells supplemented with T, while the labeling of Cer with [3H]palmitate was unaffected, that of SM was increased in all of its molecular species. Interestingly, supplementation with SMSC increased the synthesis of molecular species of Cer and SM with S, M and h-V, but not those with n-V. Finally, supplementation with both, T and SMSC, resulted in increased incorporation of [3H]palmitate in all Cer and SM molecular species. The biosynthesis of GlcCer was not influenced by T or SMSC. Thus, the de novo biosynthesis of the SM species of spermatogenic cells is subjected to endocrine stimulation by T and to paracrine regulation by soluble factor(s) released from Sertoli cells that are yet to be identified.