Is there cross-refractoriness between phospholipase A2 and the calcium ionophore A23187 in the stimulation of uterine prostaglandin production?
Phospholipase (PL) A2 increased the outputs of prostaglandin (PG) F2 alpha, PGE2 and 6-keto-PGF1 alpha from the mid-cycle guinea-pig uterus, but repeating the PLA2 treatment 1 h later failed to increase uterine PG output. Similarly, A23187 increased PG output from the mid-cycle guinea-pig uterus, but repeating the A23187 treatment 1 h later produced a very much smaller stimulatory effect. Thus the guinea-pig uterus showed complete refractoriness to PLA2 and partial refractoriness to A23187, as regards the stimulation of uterine PG production, when the uterus is treated with the same compound after an interval of 1 h. However, when the mid-cycle guinea-pig uterus was treated with PLA2 1 h after being treated with A23187, or was treated with A23187 1 h after being treated with PLA2, the second compound produced a normal stimulation of PG output and was not affected, therefore, by treatment with the first compound. Consequently, there is no cross-refractoriness between PLA2 and A23187 as regards their stimulatory effects on PG production by the guinea-pig uterus.
Department of Pharmacology, University of Edinburgh Medical School, UK.
N L
NL
Poyser
A
A
Ferguson
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology*; D004347:Drug Interactions; D005260:Female; D006168:Guinea Pigs; D010741:Phospholipases A / Q000494:pharmacology*; D054467:Phospholipases A2; D011453:Prostaglandins / Q000096:biosynthesis*; D014599:Uterus / Q000187:drug effects* / Q000378:metabolism
D011453:Prostaglandins; D000001:Calcimycin; D010741:Phospholipases A; D054467:Phospholipases A2