Prostaglandin E and F2α Receptors in Human Uterine Leiomyomas

Human uterine leiomyomas specifically bound less (P < 0.01) [3H]prostaglandin Ex (pHlPGEj) and [3H]PGF2α than adjacent normal myometria [leiomyomas: mean [3H]PGE1, 16.4 (range, 11.1–25.2) fmol/mg protein; mean [3H]PGF2α, 4.7 (range, 0.8–12.1) fmol/mg protein; adjacent normal myometria: mean [3H]PGE1; 41.7 (range 27.1–60.7) fmol/mg protein; mean [3H]PGF2α, 7.8 (range, 4.3–16.3) fmol/mg protein]. The lower binding of both [3H]PGs by leiomyomas was due to lower numbers of available high and low affinity sites. Leiomyomas and normal adjacent myometria bound 4–7 times more [3H]PGEi than [3H]PGF2α, and this appears to be due to high affinity and high numbers of low affinity PGE sites. The smooth muscle content was lower (P < 0.01) in leiomyomas (mean, 28.0%; range, 9.7–45.5%) than that of adjacent normal myometria (mean, 58.9; range, 51.4–71.2%). In summary, this is the first demonstration of PGE and PGF2α receptors in human uterine leiomyomas. Lower receptor numbers in leiomyomas appear to be due to the lower ...