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Intracellular Ca 2+ homeostasis in rat round spermatids
Author(s) -
Berrios Julio,
Osses Nelson,
Opazo Carlos,
Arenas Gloria,
Mercado Luis,
Benos Dale J,
Reyes Juan G
Publication year - 1998
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1111/j.1768-322x.1998.tb01048.x
Subject(s) - serca , thapsigargin , ionomycin , intracellular , biology , microbiology and biotechnology , plasma membrane ca2+ atpase , endoplasmic reticulum , homeostasis , fura 2 , aequorin , calcium in biology , atpase , cytosol , biochemistry , enzyme
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.