Showing papers by "Anna Spada published in 1984"

Bromocriptine Treatment Reduces the Cell Size in Human Macroprolactinomas: A Morphometric Study

Abstract: A morphological study was carried out on eight macroprolactinomas surgically removed from untreated patients and on nine macroprolactinomas removed from patients treated with bromocriptine (Brc; seven from patients treated for 6 weeks and two from patients treated for 1 yr). All treated patients had both serum PRL levels and tumor size (by computed tomographic scan) reduced. The study was carried out using light, immunofluorescence, and electron microscopic techniques and electron microscopic morphometry. By immunofluorescence microscopy, all tumors consisted of cells positive for PRL. In some treated tumors, the fluorescence was more marked than in untreated tumors. By light and electron microscopy and by morphometry, significant reductions in cell size were observed in the adenomas from Brc-treated patients. Both the cytoplasm and the nucleus shrank, but the reduction of the cytoplasm was much greater than that of the nucleus. The shrinkage of the cytoplasm was a consequence of marked involution of the ...

Presence of an adenylate cyclase dually regulated by somatostatin and human pancreatic growth hormone (GH)-releasing factor in GH-secreting cells.

Abstract: We have investigated the effects of SRIF and human pancreatic GH-releasing factor-44 (hpGRF-44) on adenylate cyclase (AC) activity of male rat anterior pituitaries (in which somatbtrophs are present in large proportion) and of human GH-secreting pituitary adenomas (which are almost homogeneously constituted by somatotrophs). The adenoma’s responsiveness to both agents in terms of secretion was previously demonstrated in in vitro experiments. SRIF inhibited in a dosedependent fashion the GH release from monolayer cultures of the tumors. The inhibition ranged from 32–66% at the maximal effective concentration (10−6 m). hpGRF-44 stimulated GH release in a dose-dependent fashion. The stimulation was 78–172% at 10−7 m. SRIF and hpGRF-44 markedly affected AC activity in both systems. SRIF elicited a pronounced inhibition of the enzyme activity in a dose-dependent manner. The inhibition was about 40% in the rat and ranged from 16–49% in adenomas at the maximal effective concentration (10−5 m SRIF). The inhibitor...