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Hypothalamus-pituitary tumours and their treatments (neurosurgery and/or radiotherapy) are major causes of acquired hypopituitarism. Scientific and clinical evidences show the positive effect of GH replacement therapy in severe adult GH deficiency (GHD) pointed toward the need of diagnostic screening of conditions at high risk for GHD. We screened 152 adults (82 males, 70 females; age: 52.3+/-1.2 years, age-range: 20-80 years, BMI: 26.4+/-0.8 kg/m(2)) in order to disclose the presence of GHD after neurosurgery for hypothalamus-pituitary tumours. The whole group (studied at least 3 months after neurosurgery) included: 111 non-functioning pituitary adenomas and 41 peri-pituitary tumours (24 craniopharyngiomas, 7 meningiomas, 5 cysts, 2 chondrosarcomas, 1 colesteatoma, 1 germinoma and 1 hemangiopericitoma). In 14 patients who underwent both neurosurgery and radiotherapy due to a tumour remnant, the somatotroph function was evaluated again 6 months after the end of radiotherapy. GHD was assumed to be shown by GH peak <5 microg/L (severe <3 microg/L) after Insulin Tolerance Test (ITT) or <16.5 microg/L (severe <9 microg/L) after GH-releasing hormone+arginine test (GHRH+ARG) (3rd and 1st centile limits of normality, respectively), two widely accepted provocative tests. Before neurosurgery GHD was present in 97/152 (63.8%) and resulted severe in 66/152 (43.4%) patients. After neurosurgery GHD was present in 122/152 (80.2%) and severe in 106/152 (69.7%). While 26 patients developed severe GHD (GHD) as consequence of neurosurgery, only one patient who had been classified as GHD before neurosurgery showed normal GH response after surgery. After neurosurgery, 91.0% (81/89) of the pan-hypopituitaric patients showed severe GHD. Considering the 14 patients who underwent also radiotherapy after neurosurgery, 7/14 had GHD before neurosurgery while 12/14 became severe GHD after radiotherapy in a context of pan-hypopituitarism. IGF-I levels below the 3rd age-related normal limits were present in 39.0% of patients in whom severe GHD was showed by provocative tests. In conclusion, this study shows that the occurrence of acquired severe GHD is extremely common in adult patients bearing non-functioning tumour masses in the hypothalamus-pituitary area and further increases after neurosurgery. All patients bearing non-functioning hypothalamus-pituitary tumours should undergo evaluation of their somatotroph function before and after neurosurgery that represents a condition at obvious more than high risk for hypopituitarism.

The diagnosis of acromegaly, in an appropriate clinical context, usually relies on lack of GH suppression below 1 microg/l during OGTT coupled with elevated IGF-I levels. On the other hand, in normal subjects glucose-induced inhibition of GH secretory bursts without any further decrease of interpulse GH levels had already been shown. Based on the foregoing, we aimed to compare the diagnostic reliability of OGTT-induced GH nadir with that recorded during 3-h spontaneous GH secretion. In 59 acromegalic patients (17 male and 42 female, age, mean +/- SE 51.5 +/- 1.9, range 21-76 yr) and in 82 normal subjects (43 male and 39 female, age, mean +/- SE 35.7 +/- 1.5, range 15-72 yr) GH secretion was evaluated every 30 min from 0 to 180 min during slow saline infusion or OGTT (75 g at 0 min). A nadir GH concentration below 1 microg/l was recorded in all normal subjects either during OGTT or saline infusion if GH secretion was evaluated over 180 min. In contrast in acromegalic patients a nadir GH concentration below 1 microg/l never occurred in both conditions. This study shows that a 3-h spontaneous GH profile is as reliable as OGTT in the diagnosis of active acromegaly.

To investigate the effects of octreotide administration on the growth rate of GH-secreting pituitary adenomas, we measured both the Ki-67 labeling index (LI) and the apoptotic index in tumor specimens from octreotide-treated or matched untreated acromegalic patients. Thirty-nine patients who received octreotide until the day of or the day before surgery and 39 untreated patients matched for sex, age, tumor size, extension, and invasiveness were studied. Immunocytochemical analysis was performed on paraffin-embedded material using a monoclonal antibody (MIB-1) directed against a proliferation-associated nuclear antigen, Ki-67, to measure the growth fraction. Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick endlabeling method, using a monoclonal antibody recognizing areas of DNA fragmentation. The Ki-67 LI and apoptosis were counted on separate slides in at least 1000 evaluable cells. Octreotide-treated patients showed a lower Ki-67 LI (1.8 +/- 0.3%) than untreated controls (3.8 +/- 0.7%; P < 0.02). Overall, the mean Ki-67 LI of treated patients was 53% lower than that in untreated patients. The antiproliferative effect of octreotide occurred independently of tumor extension and invasiveness. Octreotide-treated and untreated patients showed similar apoptotic indexes (0.6 +/- 0.2% and 0.8 +/- 0.3%, respectively). There was a positive correlation between the Ki-67 LI and the apoptotic index (r = 0.29; P < 0.03). Our study demonstrates that acromegalic patients receiving chronic octreotide treatment have a lower value of the proliferation marker Ki-67, but no significant difference in the apoptotic index compared with matched untreated patients. The antiproliferative effect of octreotide on GH-secreting adenomas should imply a lower risk of tumor growth during long-term chronic treatment with the drug.