Effects of unsaturated fatty acids on intracellular [Ca2+] signalling in rat spermatids

MADRID, C.A.; PINO, J.A.; OSSES, N.; MORENO, R.D.; ORESTI, G.M.; REYES, J.G.

Panimavida, Chile

Congreso; Reunion Anual de la Sociedad de Ciencias Fisiologicas de Chile en Panimávida, Chile Octubre 12-15 de 2011; 2011

Sociedad de Ciencias Fisiologicas

Mammalian spermatogenesis involves cell division, cell differentiation and cell death. Sertoli cells provide the structure and optimal biochemical conditions for spermatogenic development. Among other compounds, Sertoli cells secrete arachidonic acid (AA) in an FSH-dependent manner. In this work, we characterized the effects of AA and other fatty acids (FA) on [Ca2+]i homeostasis in rat round spermatids. Polyunsaturated FA (PUFA) like AA (20:4) and docosahexaenoic (22:6) or monounsaturated like oleic acid (18:1) when were exogenously added in the low micro molar range. Induced changes in [Ca2+]i in seconds, by release of intracellular Ca2+ stores and with dose-response curves characteristic for each FA. Instead, palmitic acid (saturated) up to 16 ìM, only marginally affected [Ca2+]i in these cells. All these FA did not produced changes in non-selective membrane permeability or integrity as judged by propidium iodide (PI) exclusion or LDH release. Only PUFA and oleic acid after 30 min of exposure and at concentrations 16 Ìm induced entry of PI in round spermatids. These effects of PUFA and oleic acid in round spermatids were correlated with the expression of GPR40 mRNA, a G-protein coupled membrane receptor for long chain unsaturated FA in these cells. Some of the high concentrations (>10 ìM) effects of PUFA appear correlated with direct mitochondrial uncoupling by these compounds.