
%0 Journal Article
%A Shemesh, Mordechai 
%A Dombrovski, Ludmila 
%A Gurevich, Michael 
%A Shore, Laurence S. 
%A Fuchs, Anna-Rita 
%A Fields, Michael J. 
%T Regulation of bovine cervical secretion of prostaglandins and synthesis of cyclooxygenase by oxytocin
%J Reproduction, Fertility and Development
%D 1997/11/26
%V 9
%N 5
%P 525-530
%K progesterone, indomethacin.
%R https://doi.org/10.1071/R96114
%U https://www.publish.csiro.au/paper/R96114 
%X Prostaglandin E2 (PGE2) can cause softening of the bovine cervix at oestrus when receptors for oxytocin (OT) are maximally present, indicating a relationship between OT and PGE2 production. It was therefore determined whether OT can stimulate prostaglandin synthesis or induce cyclooxygenase expression in cervical external os segments obtained from pre-oestrous&#8211;oestrous cows. Tissues were minced and incubated (50&#8211;100 mg mL-1 6 h-1) in the presence of OT (10 ng mL-1), progesterone (P4)(5 ng mL-1) and/or indomethacin (5 &#181;g mL-1). It was found that OT stimulated basal PGE2 (7&#183;79 &#177; 1&#183;22 ng 100 mg-1 , mean&#177;s.e.m.; n = 6) in external os segments from pre-oestrous&#8211;oestrous cows (P &#60; 0&#183;03), whereas P4 and indomethacin inhibited basal and OT-stimulated PGE2 production (P &#60; 0&#183;05). Basal prostaglandin F2&#945; (PGF2&#945; ) production was minimal (&#60;1 ng 100 mg-1 ) and OT had no effect on its production. Expression of cyclooxygenase was measured by Western blot analysis following incubation of the tissue (100 mg 1&#183;5 mL-1 3 h-1 ) in the presence of OT (10 ng mL-1 ) and in the presence of P4 (5 ng mL-1 ). It was found that OT stimulated the induction of cyclooxygenase II (79&#177;10%; n = 7, P &#60; 0&#183; 05). In contrast, P4 inhibited the basal expression of this enzyme (-40&#177;5%, n = 7, P &#60; 0&#183; 05) in the presence or absence of OT. It is concluded that, in vitro, OT stimulates PGE2 synthesis by the bovine cervix at oestrus and that this effect is mediated by cyclooxygenase. 
