Inhibin is a
peptide hormone normally produced by the ovary. We have previously reported that serum
inhibin concentrations are elevated in patients with granulosa cell tumours of the ovary. The aim of this study was to measure serum
inhibin in a prospective, consecutive series of 200 patients admitted for suspected
ovarian cancer. The serum
inhibin radioimmunoassay had a sensitivity of 77 mu/l. The median effective dose was 640 mu/l, while within- and between-assay coefficients of variation in the region of maximal assay precision were 4.3% and 4.3%, respectively. The average effective doses (10 and 90%) in 35 consecutive assays were 211 and 1908 mu/l, respectively. We designated a serum
inhibin concentration of > or = 130 mu/l as pathological in castrate or functionally agonadal women. Serum
inhibin concentrations were elevated in 12 of 13 post-menopausal patients with
mucinous cystadenocarcinoma of the ovary. By contrast, elevated serum
inhibin values were found in only nine of 65 women with non-mucinous
epithelial ovarian cancers. All patients showed a fall in serum
inhibin levels to below 130 mu/l by 1 week after surgery. In post-menopausal women (n = 54) with proven
ovarian cancer, serum
inhibin concentrations correlated negatively with serum FSH and the clinical stage of their disease (P < 0.05). By contrast, serum
inhibin correlated positively with serum
oestradiol and
progesterone (P < 0.001) but there was no correlation between serum inhibition and serum CA-125 values. We conclude that serum
inhibin concentrations are typically elevated in patients proven to have
mucinous cystadenocarcinoma of the ovary.(ABSTRACT TRUNCATED AT 250 WORDS)