SERUM CONCENTRATION OF HUMAN CHORIONIC GONADOTROPIN AND ITS ALPHA AND BETA SUBUNITS. 2. TROPHOBLASTIC TUMOURS

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Abstract
Using specific homologous radioimmunoassays of native hCG and its .alpha. and .beta. subunits, the levels of these glycoproteins were determined in unfiltered maternal blood serially obtained in 5 non-invasive hydatidiform moles before and after evacuation. Some of these samples were assayed after gel filtration chromatography on Sephadex G 100. Twelve samples, obtained in cases of invasive trophoblastic tumor after ablative surgery and chemotherapy, were also assessed for their hCG, hCG.alpha. and hCG.beta. content. In unaborted moles, mean circulating levels of native hCG and free hCG.beta. were considerably increased (7 and 13 times, respectively) as compared to normal pregnancies of the same age, whereas levels of free hCG.alpha. were either normal or slightly elevated. Chromatographic analyses of molar sera confirmed the presence of free circulating subunits, and separated hCG.beta. in its monomeric form from its higher molecular weight form, the latter being in greater quantity than in normal pregnancy sera. In contrast, the elution profile of serum native hCG was comparable in cases of normal and molar pregnancy. Successful curettage was accompanied by a return to normal levels of the native hCG and its .alpha. and .beta. subunits in 40-90 days. Persistence of tumor tissue was indicated by a slight increase in levels of native hCG and the .beta. subunit. Determination of .alpha. subunit level was less useful for the detection of any relapse.