We carried out biochemical studies on several prostaglandins to determine if whey would displace [3H]diazepam binding to the membranes of bovine cerebral cortex. Prostaglandins A1 and A2 were the most potent inhibitors of this binding and all the others tested were either less potent or not effective. As prostaglandins A1 and A2 competitively inhibited [3H]diazepam binding with Ki values of 7.1 +/- 0.1 and 15 +/- 1 microM, respectively, their possible function as endogenous ligands of benzodiazepine receptors warrants further attention.
Animals Cattle