Direct binding of boar ejaculate and epididymal spermatozoa to porcine epididymal epithelial cells is also needed to maintain sperm survival in in vitro co-culture.

The aim of the present study was to compare the influence of cultured epididymal epithelial cells (EEC) from corpus, caput or cauda, oviductal epithelial cells (OEC) and non-reproductive epithelial cells (LLC-PK1) on function and survival of epididymal and ejaculated spermatozoa, in the latter case to determine whether such influence differed between morphologically normal and abnormal spermatozoa. For this purpose, either spermatozoa were directly co-cultured with EEC from caput, corpus, or cauda, OEC and LLC-PK1 cells (experiment 1) or a membrane-diffusible insert was included in these co-cultures (experiment 2). EEC cultured from the three epididymal regions did not differently affect the sperm parameters.

Hexose-specificity of hexokinase and ADP-dependence of pyruvate kinase play important roles in the control of monosaccharide utilization in freshly diluted boar spermatozoa.

Incubation of boar sperm from fresh ejaculates in a minimal medium with 10 mM glucose induced a fast and intense activation of glycolysis, as indicated by the observed increases in the intracellular levels of glucose 6-phosphate (G 6-P) and ATP and the rate of formation of extracellular L-lactate. The effect of glucose was much more intense than that induced by fructose, sorbitol, and mannose. The greater utilization of glucose was related to a much greater sensitivity to hexokinase when compared with the other monosaccharides.