Glucose and lactate regulate maitotoxin-activated Ca2+ entry in spermatogenic cells: The role of intracellular [Ca2+]

Maitotoxin (MTX), a potent polyether marine biotoxin, induces Ca2+ entry in different mammalian cells by activation of Ca2+ channels. The identity and modulation of the MTX-activated Ca2+ entry pathway is not known. In this work, we show, for the first time, that glucose and lactate can modulate the excitability of spermatogenic cell MTX-activated Ca2+ channels. Physiological and pharmacological evidences indicate that glucose and lactate differentially affect MTX-activated Ca2+ entry mainly through changes that these substrates induce on intracellular Ca2+ stores and the concentration of intracellular Ca2+ ([Ca2+]i) in spermatogenic cells. Our findings strongly suggest that MTX-activated Ca2+ channels in spermatogenic cells can be regulated by a Ca2+-CaM-dependent protein kinase.