Presence of progesterone receptors and absence of oestrogen receptors in human intracranial meningioma cytosols.

The occurrence of oestrogen and progestin receptors in cytosols from human intracranial meningiomas was studied with a dextran-coated charcoal assay and Scatchard plot analysis. [3H]-Oestradiol and [3H]-promegestone (17 alpha, 21-dimethyl-19-norpregna-4,9-diene-3,20-dione, R-5020) were used as tracers. Using this method, no high-affinity binding sites for oestradiol were observed, whereas progestin binding was identified in 18 out of 20 meningioma cytosols. The number of progestin binding sites was identical in meningioma cytosols obtained from female patients (192 +/- 57 fmol/mg protein, mean +/- S.E.M., n = 12) and those obtained from male patients (230 +/- 57 fmol/mg protein, n = 6), as was the dissociation constant of the complex (1.5 +/- 0.3 vs 1.4 +/- 0.3 nmol/l respectively). Only progestins (progesterone, R-5020 and megestrol acetate) competed successfully with tritiated R-5020. Oestrogens, androgens and cortisol showed no appreciable cross-reaction. It was concluded that the cytosols from human intracranial meningiomas contain progesterone receptors in the absence of oestrogen receptors. The presence of these progesterone receptors may indicate that (anti)-progestational treatment could be of potential value in cases which cannot be treated by surgery alone.