Among 230 surgically removed pituitary adenomas, eight tumours showing immunostaining gonadotropic cells and elevated intratumours gonadotropin concentrations have been detected (frequency: 3.5 per cent.). By light microscopy the tumours were composed of agranular cells and generally PAS negative cytoplasm. The immunofluorescence technique revealed the presence of immunoreactive FSH (beta-subunit) alone in two cases, of both FSH and LH in six cases with immunoreactive beta endorphin in two of them. By electron microscopy, the cells contained an often dilated moderately or well developed rough endoplasmic reticulum, secretory granules measuring 150 nm to 200 nm which varied in electron density, and numerous microtubules. Basal plasma FSH and LH levels were simultaneously elevated in two cases; FSH levels alone were elevated in two cases; in three cases, both FSH and LH plasma values were normal. FSH and LH intratumour concentrations were simultaneously elevated in five cases; FSH alone was elevated in two cases. In all cases, the concentrations of the other hormones were negligible, except in two cases where beta endorphin concentration was elevated. The comparison of the immunocytochemical findings, the hormonal plasma levels and intratumour concentrations showed a good relationship between the immunoreactivity of the tumour and the intratumour RIA. The gonadotropic adenoma is uncommon but not rare. Its diagnosis is possible if immunocytochemical techniques are applied.

In 22 pure GH cell adenomas and 9 mixed GH cell-prolactin cell adenomas with acromegaly, we compare the morphological and functional data (secretory activity and granular appearance) with GH levels (radioimmunoassays) in the blood and in the tumor. According to morphological criteria, the secretory activity is marked in 13 cases (Group I), mild in 9 cases (Group II), and weak in 9 others (Group III). The mean values of the plasma GH levels in the 3 groups (80 ng/ml plus or minus 22; 26.5 ng/ml plus or minus 2; and 16.89 ng/ml plus or minus 2 respectively) are significantly different. In 17 densely granulated adenomas and 14 sparsely granulated adenomas, the plasma GH values were very variable. The mean levels of these 2 groups (49.76 ng/ml plus or minus 22 and 41.8 ng/ml plus or minus 7.8 respectively) are not significantly different. The GH concentrations in the tumor were also very variable (358 to 78,900 ng/mg). Their highly significant relationship with the granular appearance is an indirect proof of the granular localisation of GH. We distinguish between 4 functional aspects of the GH cell adenoma which define the different levels of synthesis, storage, and excretion. The secretory activity of the GH adenomatous cell varies with the adenomas and differs from that of the normal cell.

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