Glucose and lactate regulate maitotoxin‐activated Ca 2+ entry in spermatogenic cells: The role of intracellular [Ca 2+ ]

Maitotoxin (MTX), a potent polyether marine biotoxin, induces Ca 2+ entry in different mammalian cells by activation of Ca 2+ channels. The identity and modulation of the MTX‐activated Ca 2+ 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 Ca 2+ channels. Physiological and pharmacological evidences indicate that glucose and lactate differentially affect MTX‐activated Ca 2+ entry mainly through changes that these substrates induce on intracellular Ca 2+ stores and the concentration of intracellular Ca 2+ ([Ca 2+ ] i ) in spermatogenic cells. Our findings strongly suggest that MTX‐activated Ca 2+ channels in spermatogenic cells can be regulated by a Ca 2+ ‐CaM‐dependent protein kinase.