Prostaglandin F2 alpha decreases the affinity of epidermal growth factor receptors in Swiss mouse 3T3 cells via protein kinase C activation.

Prostaglandin F2 alpha (PGF2 alpha) selectively decreases the binding of 125I-labelled epidermal growth factor ([125I]EGF) to intact Swiss 3T3 cells. Scatchard analysis reveals that PGF2 alpha decreases the number of high-affinity EGF binding sites without changing the total number of receptors. Prostaglandins E1 (PGE1), E2 (PGE2) or F2 beta (PGF2 beta) do not alter the EGF binding to these cells and do not enhance the PGF2 alpha effect. R-59022 and R-59949, two diacylglycerol kinase inhibitors, enhance the inhibitory effect of PGF2 alpha, whereas down-modulation of protein kinase C (PKC) abolishes the effect. These results indicate that PGF2 alpha decreases EGF binding in Swiss 3T3 cells via PKC activation.