Prostaglandin production by the guinea-pig endometrium: is calcium necessary?

in Journal of Endocrinology
Authors:
S. C. Riley
Search for other papers by S. C. Riley in
Current site
Google Scholar
PubMed
Close
and
N. L. Poyser
Search for other papers by N. L. Poyser in
Current site
Google Scholar
PubMed
Close
Restricted access
Rent on DeepDyve

Sign up for journal news

ABSTRACT

The output of prostaglandin (PG) F from guinea-pig endometrium obtained on day 15 of the oestrous cycle and maintained in tissue culture was significantly (P<0·05) reduced by the use of Ca2+-depleted medium, EGTA (a Ca2+ chelator), 8-(N,N-diethyl-amino)octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8; an intracellular Ca2+ antagonist), trifluoperazine (TFP) and N-(6-aminohexyl)-5-chloro-1-naphthalenesulphonamide (W-7; both calmodulin antagonists). Nifedipine inhibited PGF output at a concentration (100 μmol/l) much greater than that usually required to block Ca2+ channels. Verapamil had a small but significant (P < 0·05) inhibitory effect on PGF output at 10–100 μmol/l. The outputs of PGE2 and, to a lesser extent, 6-keto-PGF (the hydrated product of PGI2) were also reduced by using Ca2+-depleted medium. EGTA reduced the outputs of PGE2 and 6-keto-PGF on day 1 of culture, but stimulated 6-keto-PGF output on day 3 of culture. The outputs of PGE2 and 6-keto-PGF were increased by TMB-8 (100 μmol/l) on day 3 of culture and by TFP and, to a smaller extent, by W-7 on all 3 days of culture. Nifedipine (100 μmol/l by not 1 or 10 μmol/l) reduced the outputs of PGE2 and 6-keto-PGF on all 3 days of culture, whereas verapamil (100 μmol/l but not 1 or 10 μmol/l) increased the outputs of these two prostaglandins on days 2 and 3 of culture. Phorbol 12-myristate 13-acetate (an activator of protein kinase C) had no effect on the outputs of PGF, PGE2 and 6-keto-PGF from cultured guineapig endometrium obtained on days 7 and 15 of the oestrous cycle. It is concluded that extracellular Ca2+ is necessary for the high output of PGF from the guinea-pig uterus after day 11 of the oestrous cycle, and that the action of Ca2+ is not potentiated by the activation of protein kinase C.

J. Endocr. (1987) 113, 463–471

 

  • Collapse
  • Expand