Intracellular Ca 2+ homeostasis in rat round spermatids

Berrios J.; Osses N.; Opazo C.; Reyes, J.G.; Arenas, G.; Mercado L.; Benos D.J.

Keywords: acid, proteins, rat, differentiation, enzyme, membrane, transport, fluorescence, animals, rats, protein, cell, meiosis, channel, calcium, spermatogenesis, metabolism, atpases, spermatid, male, level, inhibitor, cytology, manganese, homeostasis, indole, drug, adenosine, antagonism, inhibitors, article, mammalia, dye, ionophore, oocyte, indoles, signaling, thapsigargin, fluorescent, animal, vanadates, spermatids, derivative, ionomycin, priority, nonhuman, journal, Animalia, triphosphatase, Rats,, Wistar, 2, effect, sarcoplasmic, reticulum, endoplasmic, Triphosphatases, Ionophores, (calcium), Calcium-Transporting, cyclopiazonic, vanadic, fura, fluoroimmunoassay


Intracellular calcium, [Ca 2+](i), can regulate meiotic progression of mammalian oocytes. However, the role of [Ca 2+](i) in the regulation of the spermatogenic process and its cellular homeostatic mechanisms in spermatogenic cells has not been elucidated. Using intracellular fluorescent probes for Ca 2+ and immunodetection of plasma membrane (PM) Ca 2+-ATPases, we report that: a) rat round spermatids maintain [Ca 2+](i) levels of 60 ± 5 nM (SEM), as estimated with fluo-3 in single cells or fura-2 in cells in suspension; b) these cells regulate [Ca 2+](i), by actively extruding it using a PM Ca 2+-ATPase; c) rat spermatids also actively transport Ca 2+ by sarco-endoplasmic reticulum type ATPases (SERCA); d) rat spermatids possess non-mitochondrial intracellular Ca 2+(i) stores insensitive to thapsigargin but releasable by ionomycin; and e) rat spermatids do not activate Ca 2+ entry mechanisms by the release of Ca 2+ from SERCA-regulated stores. These results demonstrate that rat round spermatids can generate modulated intracellular Ca 2+ signals upon activation of Ca 2+ channels or Ca 2+ release from intracellular stores.

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Título de la Revista: BIOLOGY OF THE CELL
Volumen: 90
Número: 5
Editorial: Wiley
Fecha de publicación: 1998
Página de inicio: 391
Página final: 398