Cellular mechanisms by which oxytocin stimulates uterine PGF(2α) synthesis in bovine endometrium: Roles of phospholipases C and A2

P. D. Burns, G. A. Graf, S. H. Hayes, W. J. Silvia

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39 Scopus citations

Abstract

The objective of these experiments was to identify the cellular mechanisms by which oxytocin stimulates prostaglandin (PG) F(2α) synthesis in bovine endometrial tissue. Uteri were collected on the day after spontaneous luteal regression. Caruncular endometrial explants were dissected and incubated in vitro to assess PGF(2α) release or phospholipase (PL) C activity. Oxytocin (10-6 M) stimulated PGF(2α) release and PLC activity within 30 min of incubation (P < 0.01). The highest stimulation was observed at 100 min (P < 0.01). Oxytocin stimulated PLC activity at 10-9 M and higher doses, whereas an increase in PGF(2α) release was not detected until 10-8 M (P < 0.09). Melittin, a stimulator of PLA2 activity, stimulated PGF(2α) release at 10-6 M and higher doses (P < 0.01). Aristolochic acid, an inhibitor of PLA2 activity, blocked the ability of oxytocin to stimulate PGF(2α) release at 10-5 M and higher doses (P < 0.01). Aristolochic acid (10-4 M) reduced the stimulation of PGF(2α) release induced by AlF4-, a nonspecific stimulator of G protein (10-5 M) and melittin (10-4 M; P < 0.05). Aristolochic acid had no effect on the ability of oxytocin or AlF4- to stimulate PLC activity (P > 0.10). By comparing the time course of stimulation and dose-response relationships between PGF(2α) and PLC activity, it appears that oxytocin may stimulate PGF(2α) secretion by activating PLC. The effects of melittin and aristolochic acid indicate that PLA2 may play a role in mediating the stimulatory effect of oxytocin on PGF(2α) secretion, as well.

Original languageEnglish
Pages (from-to)181-191
Number of pages11
JournalDomestic Animal Endocrinology
Volume14
Issue number3
DOIs
StatePublished - May 1997

Bibliographical note

Funding Information:
Supported in part by grants from the Kentucky Agricultural Experiment Station, NtH (HD 24979), and USDA (96-35203-3495). P.D.B. was supported by NIH training grant (HD 07436) and USDA (9635203-3495). The authors are grateful to Frank Button for the care of the animals and Jim May for his assistance in the collection of uterine tissue. This report is published with the approval of the Kentucky Agricultural Experiment Station (Publication No. 96-07-156). 2 Correspondence. FAX: (606) 323-1027.

ASJC Scopus subject areas

  • Food Animals
  • Animal Science and Zoology
  • Endocrinology

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