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Background: Recent evidence has highlighted the importance of the neurosurgeon in the management of secretory pituitary tumours, but most reports are from major centres., Aims: To audit the surgical outcome of patients with acromegaly and Cushing's disease treated in a small centre (Christchurch, New Zealand) by a dedicated neurosurgeon with an interest in pituitary disease, and follow-up through an outpatient Department of Endocrinology., Methods: All cases of acromegaly and Cushing's disease admitted for surgery in Christchurch Hospital between 1984 and 2000 were audited. Data concerning preoperative findings, surgical remission rate, complications and follow-up were obtained from 44 patients (28 acromegaly, 16 Cushing's disease)., Results: Of the 28 acromegalic patients, 14 patients (50%) had a mean growth hormone level <2.5 micro g/L within the first postoperative week. Of the 15 Cushing's disease patients in whom the pituitary fossa was explored, 13 patients (87%) entered a postoperative remission, defined as an 08.00 h cortisol <200 nmol/L (normal range 250-800 nmol/L). No perioperative deaths occurred. Two of the 43 patients (4.7%) developed permanent diabetes insipidus, while eight of the 28 patients who were operated on for acromegaly (29%) eventually required some replacement treatment for hypopituitarism during follow-up (one presented with apoplexy and seven were treated with postoperative radiotherapy)., Conclusion: In a small centre with a dedicated pituitary surgeon, operative remission rates approach those obtained in larger, more specialized centres. However, given New Zealand's small, but geographically spread population, consideration should be given to establishing one or two units for the surgical management of secretory pituitary adenomas.

Factors underlying growth regulation in human pituitary tumors are largely unknown. Activin functions as an antiproliferative cytokine in a number of cell types and is endogenously expressed in normal and neoplastic human pituicytes. We investigated the effect of activin on proliferation in 16 clinically nonfunctioning pituitary adenomas in primary culture. Treatment for 24 h with activin (0-10 ng/mL) significantly inhibited cell proliferation in 5 tumors (P < 0.05), as determined by [3H]thymidine incorporation. In 9 tumors, we studied regulation of the cyclin-dependent kinase inhibitor p21WAF1/cip1 as a potential activin mediator. In tumors with activin-inhibited proliferation, p21WAF1/cip1 gene expression was up-regulated after 4 h in a dose-dependent manner (0-100 ng/mL). We also investigated tumor expression of follistatin messenger ribonucleic acid, an activin-binding protein with two isoforms of different potencies. In contrast to normal pituitary tissue, only four tumors expressed both follistatin isoforms, and three tumors expressed only the less potent form. Tumors in which activin induced antiproliferative responses showed diminished or no follistatin messenger ribonucleic acid expression compared to normal pituitary. These data indicate that activin has an antiproliferative effect in a subgroup of human pituitary tumors.