Direct evidence for a prostaglandin receptor and its application to prostaglandin measurements (rat-adipocytes-antagonists-analogues-mouse ovary assay).

A prostaglandin receptor is present in rat adipocytes, as shown by competition studies with [(3)H]-prostaglandin E(1). The affinity of the E prostaglandins for this receptor preparation is greater than that of A and F prostaglandins, an observation consistent with their relative potencies in stimulating cyclic AMP formation in isolated mouse ovaries and various other organs. In the protocol described, binding constants of 3-8 nM were obtained with prostaglandins E(2) and E(1). A sensitivity of 1 pmole makes this method readily applicable for measurement of tissue concentrations of the E prostaglandins.