Prostaglandin F2 alpha releases calcium from a thapsigargin-sensitive pool in ovine large luteal cells.
Thapsigargin (TG) and A23187 were used to examine the regulation of cytosolic free calcium (Cai2+) in ovine large and small luteal cells. Thapsigargin (50 nM) induced a sustained increase of Cai2+ in fura 2-acetoxymethyl ester (AM)-loaded cells (large = 1.32 +/- 0.07-fold, small = 1.45 +/- 0.07-fold, P < 0.05). A23187 (1 microM) induced a rapid transient increase of Cai2+ (large = 1.37 +/- 0.07-fold, small = 1.46 +/- 0.10-fold, P < 0.05). In large cells, 0.5 microM prostaglandin F2 alpha (PGF2 alpha) increased Cai2+ 1.54 +/- 0.11-fold. Pretreatment with 50 nM TG abolished the PGF2 alpha-induced calcium response. Pretreatment with PGF2 alpha attenuated (P < 0.05) the TG-induced Cai2+ increase. Progesterone secretion was significantly (P < 0.05) inhibited by incubation with 50 nM TG, 1 microM A23187, and 0.5 microM PGF2 alpha in large but not small cells. These data suggest that PGF2 alpha releases calcium from a TG-sensitive intracellular calcium pool in ovine large luteal cells.
Wegner
J A
JA
Department of Physiology, Arizona Health Sciences Center, University of Arizona, Tucson 85724.
Martinez-Zaguilan
R
R
Gillies
R J
RJ
Hoyer
P B
PB
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D003338:Corpus Luteum / Q000166:cytology / Q000378:metabolism*; D015237:Dinoprost / Q000494:pharmacology*; D004721:Endoplasmic Reticulum / Q000502:physiology; D005260:Female; D007425:Intracellular Membranes / Q000378:metabolism; D011374:Progesterone / Q000378:metabolism; D012756:Sheep; D013729:Terpenes / Q000494:pharmacology*; D019284:Thapsigargin
D013729:Terpenes; D000001:Calcimycin; D011374:Progesterone; D019284:Thapsigargin; D015237:Dinoprost; D000252:Calcium-Transporting ATPases; D002118:Calcium