There is high risk for H in TBI and SAH patients. Early diagnosis of PH is always confirmed in the long term. Pituitary function in brain-injured patients may improve over time but, although rarely, may also worsen. Thus, brain-injured patients must undergo neuroendocrine follow-up over time.

In a retrospective study of patients with pNETs, we found a significant association between metformin use and longer PFS.

IGF-I is the best marker of GH secretory status but it also depends on the nutritional status and peripheral hormones such as insulin, glucocorticoids, thyroid hormones and gonadal steroids. Though monitoring IGF-I levels is the best way for evaluating appropriate GH replacement, the usefulness of IGF-I assay in the diagnosis of adult GH deficiency (GHD) is still matter of debate. To clarify this point in a large population of GHD adults (no. = 135, 61 women and 74 men; age, mean +/- SE: 43.8 +/- 1.4 yr, range 20-80 yr) we studied IGF-I levels, their reproducibility and association to peak GH response to GHRH + arginine (GHRH + ARG) test and insulin tolerance test (ITT). The results in GHD were compared with those in a large population of normal subjects (no. = 336, 233 women and 103 men, aged 20-80 yr). Mean IGF-I levels in GHD (77.8 +/- 4.9 micrograms/l) were clearly lower (p < 0.001) than those in normal subjects (170.2 +/- 4.7 micrograms/l). In Childhood Onset GHD (CO-GHD; no. = 40; age, mean +/- SE: 27.8 +/- 1.5 yr) IGF-I levels were lower than those in Adult Onset GHD (AO-GHD; no. = 95, age, mean +/- SE: 50.7 +/- 1.4 yr) (56.6 +/- 9.7 vs 87.1 +/- 5.4 micrograms/l, p < 0.0003). In both GHD and normal subjects IGF-I levels showed good, reproducibility (r = 0.92, p < 0.00001 and r = 0.62, p < 0.00001, respectively). In GHD, but not in normal subjects, IGF-I levels were positively associated to peak GH responses to GHRH + ARG (r = 0.57, p < 0.00001); on the other hand, the GH peak after ITT was not associated to IGF-I in GHD. In normal subjects, but not in GHD, IGF-I levels were negatively associated to age (r = -0.60, p < 0.00001). Considering individual IGF-I levels there was a clear overlap between GHD and normal subjects. However, this overlap was strongly dependent on age. In fact, in the third and fourth decade of life 83.6% of GHD had IGF-I levels below the 3rd centile of normal values; on the other hand, in the fifth-sixth decade and in ageing 47% and only 12% of GHD, respectively, had IGF-I levels low for age. In conclusion, our results demonstrate that IGF-I levels represent a reproducible marker of GH status and are reduced more in CO-GHD than in AO-GHD adults. An overlap exists between GHD and normal subjects, however this is small up to the 4th decade of life. Thus, though normal IGF-I levels do not rule out the existence of GHD, up to 40 yr low IGF-I levels strongly point to GHD if malnutrition and liver disease have been ruled out.

Cabergoline (CAB), a new long-acting ergoline derivative, was shown to be very effective in reducing PRL levels in normal volunteers and in hyperprolactinemic patients. We evaluated the hormonal changes after discontinuation of long-term therapy with CAB as well as the safety of drug exposure during pregnancy both for mothers and babies. We therefore studied 48 patients (47 females and one male) with pathological hyperprolactinaemia (mean +/- SE, 117.2 +/- 15.2: median 73.2 micrograms/l), treated for 1-82 months (mean +/- SE, 28.3 +/- 3; median 18). After long-term treatment, CAB was withdrawn in 11 patients and PRL levels were persistently normal for almost 15 days and significantly lower (p < 0.05) than basal at 30, 45, 60, 90, 120 days. Three patients had normal PRL levels still at 45 days after treatment discontinuation. Nine patients became pregnant after 1-37 months (mean 12.4) of therapy. In two patients the pregnancy was interrupted spontaneously in one case and voluntarily in the other. In all but one patients after delivery or three-month breast feeding, PRL levels trended towards reduction. In two cases (one with microadenoma and one with idiopathic hyperprolactinaemia) PRL remained in the normal levels for 1-3 years after delivery. In conclusion CAB is able to inhibit plasma PRL levels for long time (up to 120 days) after withdrawal in patients with pathological hyperprolactinaemia treated with long-term therapy.

Funding: The study was not funded. Acknowledgements: We would like to thank all the members of the Fluid and Electrolytes Disorder Club of the Italian Society of Endocrinology, for the scientific support during the writing of the manuscript.

Introduction Management of malignant insulinomas is challenging due to the need to control both hypoglycaemic syndrome and tumor growth. Literature data is limited to small series. Aim of the study To analyze clinico-pathological characteristics, treatments and prognosis of patients with malignant insulinoma. Materials and methods Multicenter retrospective study on 31 patients (male: 61.3%) diagnosed between 1988 and 2017. Results The mean age at diagnosis was 48 years. The mean NET diameter was 41 ± 31 mm, and 70.8% of NETs were G2. Metastases were widespread in 38.7%, hepatic in 41.9% and only lymph nodal in 19.4%. In 16.1% of the cases, the hypoglycaemic syndrome occurred after 46 ± 35 months from the diagnosis of originally non-functioning NET, whereas in 83.9% of the cases it led to the diagnosis of NET, of which 42.3% with a mean diagnostic delay of 32.7 ± 39.8 months. Surgical treatment was performed in 67.7% of the cases. The 5-year survival rate was 62%. Overall survival was significantly higher in patients with Ki-67 ≤10% (P = 0.03), insulin level <60 µU/mL (P = 0.015) and in patients who underwent surgery (P = 0.006). Peptide Receptor Radionuclide Therapy (PRRT) was performed in 45.1%, with syndrome control in 93% of patients. Conclusions Our study includes the largest series of patients with malignant insulinoma reported to date. The hypoglycaemic syndrome may occur after years in initially non-functioning NETs or be misunderstood with delayed diagnosis of NETs. Surgical treatment and Ki67 ≤10% are prognostic factors associated with better survival. PPRT proved to be effective in the control of hypoglycaemia in majority of cases.

It is known that spontaneous and stimulated GH secretion is reduced in obesity. On the other hand, it has been recently reported that, in obese subjects, plasma GH levels did not change during a hyperglycemic clamp. To further study the sensitivity of somatotrope cells to inhibitory influences in obesity, we studied the effect of somatostatin, pirenzepine, or glucose on the GH response to GHRH or arginine in 32 obese patients and 30 controls. Basal GH levels were lower in obese than in normal subjects (1.0 +/- 0.6 vs. 4.8 +/- 0.7 micrograms/L, P < 0.05), while insulin-like growth factor-I levels were similar in both groups (137.3 +/- 13.2 vs. 138.8 +/- 12.2 micrograms/L). In obese as well as in control subjects pirenzepine abolished the GH response to either GHRH (AUC0-120: 43.7 +/- 9.6 vs. 258.3 +/- 59.9 micrograms/L/h, P < 0.04 and 113.0 +/- 75.0 vs. 870.5 +/- 255 micrograms/L.h, P < 0.01, respectively) or arginine (6.5 +/- 2.5 vs. 118.7 +/- 55.9 micrograms/L.h, P < 0.05 and 47.7 +/- 7.3 vs. 334.0 +/- 157.5 micrograms/L.h, P < 0.01, respectively). Differently from pirenzepine, glucose blunted the GH response to either GHRH or arginine in control subjects (260.8 +/- 38.3 vs. 479.5 +/- 83.9 micrograms/L.h, P < 0.03 and 294.8 +/- 46.3 vs. 625.1 +/- 139.1 micrograms/L.h, P < 0.05, respectively), but failed to modify it in obese patients (193.7 +/- 39.4 vs. 172.4 +/- 33.6 micrograms/L.h and 121.1 +/- 43.4 vs. 155.1 +/- 39.7 micrograms/L.h, respectively). On the other hand, somatostatin deeply blunted the GHRH-induced GH release in obese patients (58.5 +/- 25.4 vs. 548.7 +/- 196.6 micrograms/L.h, P < 0.05) as well as in controls (181.4 +/- 44.4 vs. 759.7 +/- 46.6 micrograms/L.h, P < 0.04). In conclusion, our results show that, in obesity, the stimulated GH release is refractory to the inhibitory effect of glucose but not of pirenzepine, in spite of their likely common mechanism of action, i.e. increase of hypothalamic somatostatin release. Exogenous somatostatin is able to abolish GH secretion both in normal and obese subjects. These data suggest the existence of a peculiar inhability of hyperglycemia to trigger somatostatinergic release in obesity.

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