Effect of bromocriptine, somatostatin, and oestradiol-17 β on hormone secretion and ultrastructure of human pituitary tumours in vitro

1981 ◽  
Vol 98 (1) ◽  
pp. 14-23 ◽  
Author(s):  
R. A. Prysor-Jones ◽  
S.J. Kennedy ◽  
J. P. O'Sullivan ◽  
J. S. Jenkins

Abstract. The effect of bromocriptine and somatostatin on hormone secretion and the ultrastructure of human pituitary adenomas was studied in vitro. Prolactin secretion was inhibited by bromocriptine in 3 out of 10 prolactin-secreting tumours and in explants from 2 normal pituitaries. GH secretion was reduced by bromocriptine in 4 out of 6 GH-secreting adenomas but was not affected by the drug in the incubations of normal pituitaries. Somatostatin inhibited GH secretion in 2 out of 5 pituitary adenomas and the effect was comparable with that of bromocriptine. Incubation of prolactin-secreting adenomas with oestradiol for as long as 24 days produced no change in hormone secretion. Examination of tumour explants by electron microscopy showed that somatostatin and bromocriptine produced accumulation of secretion granules but no changes in the secretory organelles. Long term bromocriptine treatment of 'nude' athymic mice bearing xenografts of human pituitary adenomas suppressed hormone secretion and produced some increase in secretion granules but there were no morphological changes in the secretory organelles or other vital structures of the adenoma cells.

1987 ◽  
Vol 116 (1) ◽  
pp. 81-84 ◽  
Author(s):  
Miyuki Ishibashi ◽  
Tohru Yamaji ◽  
Fumimaro Takaku ◽  
Akira Teramoto ◽  
Takanori Fukushima ◽  
...  

Abstract. The effect of GnRH-associated peptide on PRL secretion by human pituitary lactotropes in culture was studied. Pituitary adenomas obtained at selective transsphenoidal adenomectomy from a patient with prolactinoma, and two patients with mixed GH- and PRL-secreting pituitary adenomas were cultured in monolayer. When cells were incubated with dopamine (10 nmol/l), a significant inhibition in PRL secretion was observed in all the experiments, which was blocked by co-incubation with haloperidol. In mixed GH- and PRL-secreting adenoma cells, dopamine likewise decreased GH secretion. Incubation of cells with synthetic GnRH-associated peptide at concentrations up to 100 nmol/l, on the other hand, failed to affect both PRL and GH secretion. These results suggest that synthetic GnRH-associated peptide has no inhibitory effect on PRL secretion in human pituitary lactotropes.


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