Cyclic Ca2+ changes in intracellular stores of gonadotropes during gonadotropin-releasing hormone-stimulated Ca2+ oscillations.
Gonadotropin-releasing hormone induces oscillatory release of Ca2+ from inositol trisphosphate-sensitive stores of gonadotropes. Simultaneously with electrophysiological measures of cytoplasmic [Ca2+], corresponding changes in [Ca2+] within intracellular stores were monitored with a fluorescent dye, mag-indo-1. Each cycle of oscillation released only 10% of the detectable stored Ca2+. Some Ca2+ was recovered by the stores using a mechanism sensitive to inhibitors of intracellular Ca2+ ATPases, and much of the remainder was temporarily and rapidly pumped into other intracellular compartments or out of the cell. The dynamics of Ca2+ oscillations are thus more complex than a repeated emptying and refilling of a single compartment. The free concentrations measured show that intracellular Ca2+ store compartments contain strong Ca2+ buffers.
Tse
F W
FW
Department of Physiology and Biophysics, University of Washington, Seattle 98195.
Tse
A
A
Hille
B
B
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006873:Hydroquinones / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D009991:Oscillometry; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin; D013997:Time Factors
D006873:Hydroquinones; D013729:Terpenes; C019359:2,5-di-tert-butylhydroquinone; D007987:Gonadotropin-Releasing Hormone; D019284:Thapsigargin; D000252:Calcium-Transporting ATPases; D002118:Calcium