In vitro control of prostaglandin F2a synthesis in bovine endometrium

Abstract

Synthesis of endometrial prostaglandin F2± (PGF2±) results from a complex cascade of highly coordinated intracellular events. Production of PGF2± can be stimulated by mellitin and 12, 13 phorbol dibutyrate (PDBu). Objective of the present study was to verify whether basal or stimulated synthesis of PGF2± was dependent on de novo protein synthesis. In Experiment 1, endometrial explants from cyclic, non-lactating cross-bred beef cows (n=2) on day 15 of the estrous cycle were incubated in quadruplicate in culture KHB culture medium or medium supplemented with 10-6M PDBu, 10-6M melittin or 10-5M melittin. Medium samples were collected immediately and 60 minutes after treatment administration and concentration of PGF2± in medium were measured by radioimmunoassay. Concentrations of PGF2± in medium were higher (P<0.06) after treatment with PDBu in comparison with control and melittin. In Experiment 2, endometrial explants from cyclic, non-lactating cross-bred beef cows (n=4) on day 17 of the estrous cycle were incubated in quadruplicate in medium supplemented with 0, 50, 100 or 200mg cyclohexamide (CHX) and 0 or 100ng/ml PDBu, in a 4 x 2 factorial arrangement. Medium samples were collected immediately and 60 minutes after administration of treatments and concentrations of PGF2± measured by radioimmunoassay. Endometrial integrity was was evaluated by histology. Treatment with PDBu stimulated production of PGF2± (P<0.01), regardless of concentration of CHX used. The CHX did not affect production of PGF2±, either in the presence or absence of PDBu. Histological integrity of explants was preserved. It was concluded that both basal and PDBu-stimulated PGF2± production are not dependent on new protein sythesis.