Hormone secretion by cell culture of human GH-PRL secreting pituitary adenomas: effects of bromocriptine

DNA-flow cytometry of 207 pituitary adenomas: ploidy, proliferation, and prognosis

The principal factors involved in pituitary adenoma formation are unknown. DNA-flow cytometry is a useful study providing an estimation of a tumor proliferative rate. In this study, DNA-flow cytometry was performed to evaluate its capability to both assess prognosis and predict recurrence. Two hundred and seven fresh pituitary adenoma specimens were assessed by flow cytometry. Pre-operative endocrine function, previous medical treatment, radiographic appearance, surgical findings and immunohistochemistry were recorded for each patient. Patient outcomes were assessed at a mean follow-up of 5.3 +/- 3.1 yr. Endocrinologically inactive pituitary adenomas were predominantly euploids (50.8%). The highest proliferation rates occurred in Nelson's syndrome and the lowest in Cushing's disease. A significant difference in proliferation was observed with prolactinomas and acromegaly when a medical treatment was performed before primary surgery. Massive histological invasiveness was directly associated with a significant increase in proliferation rate. Radiotherapy did not affect the recurrence rate (4.4%) statistically. In conclusion, DNA-flow cytometry was found to be useful for determining ploidy and obtaining an overview of cell cycle status. It was helpful in identifying patients requiring closer follow-up, such as those with invasive adenomas and Nelson's syndrome. No single parameter revealed by DNA-flow cytometry could predict tumor prognosis or recurrence in the follow-up of 7.5 +/- 1.3 yr.

The role of protein kinase C and its effect on GHRH in the regulation of hormone secretion by somatotrophinomas

Phorbol ester-induced release of growth hormone (GH) and prolactin (PRL) from human somatotrophic tumors was examined in vitro. 12-O-tetradecanoyl-phorbol-13-acetate (TPA) strongly stimulated GH and PRL secretion and showed an additive effect on GH secretion if used in combination with GH releasing hormone (GHRH). In contrast, staurosporine exerted a variable inhibitory effect on GH release. There was no correlation between such effects and gsp mutations. The findings suggested that TPA doesn't act directly through cAMP signal transduction system.