Extracellular ATP stimulates estradiol secretion in rat Sertoli cells in vitro: modulation by external sodium.
In this study, we examined the effects of extracellular ATP (ATPe) on [Ca(2+)](i), [Na(+)](i), plasma membrane potential changes and estradiol secretion in rat Sertoli cells. ATPe caused a rapid rise of [Ca(2+)](i) with an initial spike followed by a long lasting plateau. The first rapid spike was dependent on the release of Ca(2+) from internal stores as it also occurred in Ca(2+)-free medium while the long lasting plateau phase was dependent on Ca(2+) influx from the external medium. ATPe stimulated a rapid plasma membrane depolarization that was dependent on an influx of Na(+) from the external medium as demonstrated by plasma membrane potential monitoring in Na(+)-free medium and by [Na(+)](i) measurement with the Na(+)-sensitive fluorescent dye SBFI. ATPe stimulated estradiol secretion in a dose dependent manner and was fully dependent on the presence of Na(+) in the external medium while the presence of Ca(2+) was not necessary. Among the different nucleotides tested, only ATP, ATP-5'-[gamma-thio]triphosphate, UTP, alpha,beta-methylene-ATP were effective in stimulating estradiol secretion. These results demonstrate that rat Sertoli cells possess P2-purinergic receptors belonging to the P2X and P2Y subfamily which activation induces [Ca(2+)](i) and [Na(+)](i) rise and Na(+)-dependent plasma membrane depolarization leading to estradiol secretion.
Rossato
M
M
Department of Medical and Surgical Sciences, Clinica Medica 3, University of Padova, Via Ospedale 105, 35128, Padova, Italy.
Merico
M
M
Bettella
A
A
Bordon
P
P
Foresta
C
C
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D004958:Estradiol / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009711:Nucleotides / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012708:Sertoli Cells / Q000187:drug effects* / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology
D009711:Nucleotides; D004958:Estradiol; D000255:Adenosine Triphosphate; D012964:Sodium; D002118:Calcium