SHORT-TERM STUDIES OF OVARIAN METABOLISM IN THE EWE

The ovarian uptake of metabolites in anaesthetised ewes was determined . In both studies, catheters were inserted into the ovarian vein and f emoral artery, and Transonic flow transducers were placed around the o varian arterio-venous plexus. Arterio-venous differences in glucose, l actate, free fatty acids (FFA), 3-hydroxybutyrate (3-OHB), acetate, ch olesterol and progesterone and oestradiol-17 beta levels were determin ed every 10 min over a 3.5 h period. In study one, glucose uptake was significant in three sheep, and one sheep only had a significant uptak e of FFA. Ovarian 3-OHB uptake was significant in two sheep. Significa nt uptake of acetate or cholesterol was identified in one sheep. Proge sterone secretion was significant in three sheep and two sheep had sig nificant progesterone uptake. In study 2, glucose uptake was significa nt in four sheep and lactate release was significant in the same sheep . There was uptake of FFA and 3-OHB, cholesterol, and acetate in each of three different sheep. Oestradiol-17 beta output was significant fo r sheep in oestrus and prooestrus. While the effects of gonadotrophin- releasing hormone (GnRH) treatment were confounded by time spent under anaesthesia, exogenous GnRH appeared to have no significant effect on the uptake of most metabolites and steroid hormone outputs. The metab olic requirements for energy and precursors for progesterone was small . Glucose was the major source of energy for the ovary and appears to be metabolised through anaerobic pathways, as indicated by significant lactate output. (C) 1997 Elsevier Science B.V.