Endocrine Abstracts

Polyunsaturated fatty acids (PUFAs) supply precursors for prostaglandin (PG) synthesis and PGs in turn influence many aspects of reproduction. We have previously demonstrated that supplementation of the diet of dairy cows with the n-6 PUFA [linoleic acid (LA)] significantly inhibited uterine PG production. In this study we have investigated the effects of various n-6 PUFAs in vitro on PG production by ovine endometrial cells.

Endometrial tissue was collected on Days1-2 after oestrus. Uterine endometrial epithelial cells were isolated using pancreatin dispase digestion and cultured to confluence in DMEMF12 medium containing 10 percent fetal calf serum. This was replaced with serum free medium and the cells were supplemented with different n-6 PUFAs over the dose range 0-100 micromolars: LA, gamma-linolenic acid (GLA) and arachidonic acid (AA). Oleic acid (OA) was used as a control. Following a further 3 days culture in PUFA containing medium cells were exposed to either the same control medium (CM) or oxytocin (OT: 250 nanomolar). Spent medium was collected at 2 and 24 h post challenge for measuring PGF2alpha by radioimmunoassay. Each treatment was replicated with cells from at least 3 sheep.

OT stimulated PGF2alpha production as expected. Chronic pre-treatment of endometrial cells with LA (100 micromolar) significantly inhibited PGF2alpha generation in response to subsequent exposure to either CM or OT (P<0.05). As expected, pre-exposure to OA had no effect on PG synthesis whilst AA and GLA dose-dependently stimulated PG production by 4-10 fold at all sampling times in both CM and OT treated cells (P<0.05-0.01). These results suggest that PUFA supplementation significantly affects PGF2alpha production by endometrial cells both basally and in response to OT. The precise effect is dependent on the position of the PUFA in the PG biosynthetic pathway.

This work is supported by the BBSRC.