We have cloned the FP receptor from rat corpus luteum and human uterus cDNA libraries, respectively. The coding DNA sequence in the rat cDNA is 1101 bp and is similar to the mouse cDNA coding for a receptor protein of 366 amino acids. The human sequence shows a 5 bp deficiency in the 3' region, truncating the coding sequence to 359 amino acids. Northern blot analysis indicates highest expression in the ovary. Cell lines have been established giving stable expression of the FP receptor. Activation of the cloned FP receptor gave an increase in intracellular calcium, indicating signaling via phospholipase C-mediated phosphoinositide turnover. Using [3H]PGF2 alpha, binding of PGs showed the rank order of fluprostenol > PhXA70 > PGF2 alpha > or = PhXA85 > PGD2 > PGE2.