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To evaluate the prevalence of resistance to cabergoline treatment, we studied 120 consecutive de novo patients (56 macroadenoma, 60 microadenoma, 4 nontumoral hyperprolactinemia) treated with cabergoline (CAB) compared with 87 consecutive de novo patients (28 macroadenoma, 44 microadenoma, 15 nontumoral hyperprolactinemia) treated with bromocriptine (BRC) for 24 months. Resistance was evaluated as inability to normalize serum PRL levels (first end point) and to induce tumor shrinkage (second end point).After 24 months, PRL normalization and tumor shrinkage after CAB and BRC treatments, respectively, were obtained in 82.1% and 46.4% of macroprolactinomas (P < 0.001) and in 90% vs. 56.8% of microprolactinomas (P < 0.001). The median doses of CAB and BRC able to fulfill the two criteria of treatment success were 1 mg/wk and 7.5 mg/d in macroprolactinomas, 1 mg/wk and 5 mg/d in microprolactinomas, and 0.5 mg/wk and 3.75 mg/d in nontumoral hyperprolactinemia. Hyperprolactinemia persisted in 17.8% of macroprolactinomas, 10% of microprolactinomas, and after CAB at doses of 5-7 mg/wk and in 53.6% of macroprolactinomas, 43.2% of microprolactinomas, and 20% of nontumoral hyperprolactinemic patients, after BRC at doses of 15-20 mg/d. In these resistant macro-and microprolactinomas, the maximal tumor diameter was reduced by 43.7 ؎ 3.6% and 22.1 ؎ 3.7% and by 59.3 ؎ 7.1% and 4.3 ؎ 2.1% after CAB and BRC, respectively (P < 0.001).In conclusion, long-term CAB treatment induced the successful control of hyperprolactinemia associated with tumor shrinkage in a higher proportion of patients than did BRC treatment. In a small number of patients (i.e. 17.8% of macroprolactinomas and 10% of microprolactinomas), however, CAB treatment did not normalize serum PRL levels despite reducing tumor mass, even at very high doses. Therefore, an absence of tumor shrinkage cannot be considered as end point to indicate resistance to CAB, and increasing the dose of CAB higher than 3 mg/wk does not seem to be helpful in controlling PRL hypersecretion. (J Clin Endocrinol Metab 86: 5256 -5261, 2001) Patients and Methods PatientsFrom 1996 to 1998, 120 consecutive de novo patients with hyperprolactinemia (90 women and 30 men, aged 15-72 yr) were admitted to our Department and were included into this study after their informed Abbreviations: BRC, Bromocriptine; CAB, cabergoline; CT, computed tomography; DA, dopamine agonist; MRI, magnetic resonance imaging.

Recently, the medical approach to patients with secreting and clinically non-functioning pituitary adenomas has received great impulse thanks to the availability of new, selective and long-lasting compounds with dopaminergic activity, such as cabergoline, and of somatostatin analogues provided in slow-release formulations, such as lanreotide and octreotide long acting release (LAR). In particular, the use of cabergoline has induced control of hyperprolactinaemia and tumour shrinkage in the great majority of patients with micro- and macroprolactinomas. Cabergoline treatment restores fertility both in women and men, and partially improves osteoporosis, one of the major complications of hyperprolactinaemia. In acromegaly, disease control (growth hormone [GH] <2.5–1.0 μg/l as a fasting or glucose-suppressed value, respectively, together with age-normalised insulin-like growth factor [IGF]-I) is achievable in more than half of patients receiving treatment with lanreotide or octreotide-LAR. Improvement in cardiomyopathy, sleep apnoea and arthropathy has been reported during GH/IGF-I suppression after pharmacotherapy. A synthetic GH analogue, B2036-PEG, that antagonises endogenous GH binding to its receptor-binding sites and a GH-releasing hormone antagonist that blocks the effect of this releasing factor on the hypothalamus and pituitary are presently under investigation in acromegaly. Preliminary studies have clearly demonstrated the effectiveness of the GH receptor antagonist in suppressing IGF-I levels in acromegalic patients previously unresponsive to somatostatin analogues. Beneficial effects of subcutaneous octreotide and lanreotide have also been reported in adenomas secreting thyroid-stimulating hormone, while the results of treatment with dopamine agonists or somatostatin analogues remain disappointing in patients with clinically non-functioning adenomas. In these patients the possibility of visualising in vivo the expression of D₂ receptors using specific radiotracers such as ¹²³I-methoxybenzamide has allowed selection of patients likely to respond to cabergoline. Scant effects of pharmacotherapy have also been reported in patients with adenomas secreting adrenocorticotropic hormone. However, some preliminary data suggest a potential use of cabergoline in combination with ketoconazole, or alone, in selected cases of Cushing’s disease or Nelson’s syndrome.

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This single-center open sequential study aimed at comparing the efficacy of a 6-month treatment with lanreotide (LAN) (60-90 mg/month i.m.), to that of octreotide (OCT) (0.3-0.6 mg/day s.c.) in 45 patients with active acromegaly (GH, 63.2+/-12.1 ng/ml, IGF-I, 757+/-67.1 ng/ml). After 6 months of OCT treatment, safe GH (fasting <2.5, glucose suppressed <1 ng/ml) and IGF-I (normalized for age) levels were achieved in 23 patients. After treatment withdrawal, GH levels significantly increased in all patients, though remaining slightly lower than pre-OCT therapy (39.2+/-5.8 ng/ml) while plasma IGF-I levels were unchanged (654+/-59.4 ng/ml). After 6 months of LAN treatment, safe GH and IGF-I levels were achieved in 26 patients (57.7%). After OCT or LAN treatments, no significant difference was found between nadir GH (6+/-1 vs 5.9+/-1.1 ng/ml) and IGF-I levels (281+/-23.3 vs 262+/-20.6 ng/ml). Four out of the 20 patients poorly responsive to OCT achieved safe GH and IGF-I levels after LAN treatment. Among the 20 non-operated patients, a significant tumor shrinkage was documented by CT and/or MRI in 5 patients after OCT and in 1 patient after LAN treatment. All patients referred a notable improvement of soft tissue swelling, arthralgia, headache and weakness, both after OCT and LAN treatments. During the first days of OCT treatment, abdominal discomfort was referred by 12 patients and steatorrhea by 5 patients: side effects disappeared spontaneously in 6 cases while during treatment with pancreatic enzymes in the remaining ones. After the first injections of LAN, abdominal discomfort was referred by 10 patients and steatorrhea by 2 of them. No difference in the prevalence of both early and late side effects was noted after treatment with OCT and LAN (chi2, 0.49). The majority of these poorly tolerant patients had side effects with both compounds. During LAN treatment, side effects were mild and spontaneously disappeared but recurred after the injection of the drug in six patients. Gallstones were detected in one patient during OCT and in another during LAN, sludge was noted in 6 patients after OCT and in 2 after LAN treatment. In conclusion, the treatment with LAN allowed to achieve safe GH and IGF-I levels in 57.7% of acromegalics with an excellent patients' compliance. LAN treatment possessed similar efficacy and caused side effects with a similar incidence of OCT treatment. The recurrence of side effects after LAN injection suggests the necessity of a careful monitoring of adverse reactions.

To investigate the relationships between the GH-IGF-I axis and the atherosclerotic profile, we designed this open, observational, prospective study. Peak GH after GHRH+arginine (ARG) test, serum IGF-I and IGF binding protein-3 (IGFBP-3), lipid profile, homeostasis model assessment (HOMA) index and intima-media thickness (IMT) at common carotid arteries were measured in 174 healthy individuals (92 women, 82 men, aged 18-80 yr). Exclusion criteria for this study were: 1) body mass index (BMI) > or = 30 kg/m2; 2) personal history of cardiovascular diseases; 3) previous or current treatments of diabetes or hypertension; 4) previous corticosteroids treatment for longer than 2 weeks or estrogens for longer than 3 months; 5) smoking of more than 15 cigarettes/day and alcohol abuse. Subjects were divided according to age in decade groups from < 20 to > 70 yr. BMI increased with age, as did systolic and diastolic blood pressures, although they remained in the normal range. The GH peak after GHRH+ARG test was significantly higher in the subjects aged < 20 yr than in all the other groups (p < 0.01), but was similar in the remaining groups. An inverse correlation was found between the IGF-I z-score and total/HDL-cholesterol ratio (p = 0.02) and mean IMT (p = 0.0009); IGFBP-3 z-score and mean IMT (p = 0.043); IGF: IGFBP-3 molar ratio and total/HDL-cholesterol ratio (p < 0.0001) and mean IMT (p < 0.0001). Atherosclerotic plaques were found in 7 out of 12 subjects (53.8%) with a z-IGF-I score from < or = -2 to -1, in 4 out of 63 (6.3%) with a z-IGF-I score from -0.99 to 0.1 out of 66 (1.5%) with a z-IGF-I score from 0.1 to 1 and none of the 33 subjects with an IGF-I z-score >1 (p = 0.006). At multi-step regression analysis, age was the best predictor of HDL-cholesterol levels and mean IMT, IGF-I level was the best predictor of total cholesterol and total/HDL-cholesterol ratio, the IGF-I/IGFBP-3 molar ratio was the best predictor of triglycerides levels. The z-scores of IGF-I and IGFBP-3 were the second best predictors of mean IMT after age. In conclusion, IGF-I and IGFBP-3 were negatively correlated with common cardiovascular risk factors, studied as total/HDL-cholesterol ratio, and/or early atherosclerosis, studied as IMT at common carotid arteries. The prevalence of atherosclerotic plaques, though not hemodinamically significant, was higher in the subjects having a z-score of IGF-I of < or = -2 to -1. Our results support a role of the IGF/IGFBP-3 axis in the pathogenesis of atherosclerosis.

Purpose This study was aimed at evaluating sirtuin 4 (Sirt4) levels in obese individuals, in relation to their adherence to the Mediterranean diet (MD), a healthy dietary pattern characterized by high antioxidant capacity, and markers of visceral fat storage. Subjects/Methods Forty-three obese patients (44% males; BMI: 36.7–58.8 kg/m2) were consecutively included. PREvención con DIeta MEDiterránea (PREDIMED) and the 7-day food records were used to assess the adherence to MD and dietary pattern, respectively. Visceral adiposity index (VAI) was calculated. Sirt4 levels were detected by ELISA method. Results The majority of the obese participants (62.8%) had an average adherence to MD. Compared with average adherers, low adherers had higher BMI, energy intake, and percentage of energy from lipids, mainly saturated fat and polyunsaturated fatty acids (PUFA), and lower Sirt4 levels. After adjusting for BMI, Sirt4 levels remained negatively correlated with VAI. After adjusting for total energy intake, Sirt4 levels remained negatively associated with PREDIMED and consumption of n-3 PUFA, vitamins C and E. The threshold value of PREDIMED predicting the lowest decrease in Sirt4 levels was found at a score of 6. Conclusions Less reduced Sirt4 levels in obese patients adhering to MD suggest a further aspect of the antioxidant advantage of MD.

Morbidly obese subjects are characterized by multiple endocrine abnormalities and these are paralleled by unfavorable changes in body composition. In obese individuals, either 24-h spontaneous or stimulated GH secretion is impaired without an organic pituitary disease and the severity of the secretory defect is proportional to the degree of obesity. The GHRH+arginine (GHRH+ARG) test is likely to be the overall test of choice in clinical practice to differentiate GH deficiency (GHD) patients. Similarly to other provocative tests, GHRH+ARG is influenced by obesity per se. Therefore, a new cut-off limit of peak GH response of 4.2 microg/l in obese subjects has been recently assumed. The aim of the present study was to investigate the reciprocal influence between decreased GH secretion and body composition in a group of 110 morbidly obese subjects, using the new cut-off limit of peak GH response to GHRH+ARG test for these subjects. In our study, GHD was identified in 27.3% of the obese subjects, without gender difference. In GDH obese subjects body mass index (BMI), waist circumference, waist-to-hip ratio (WHR), fat mass (FM), and resistance (R) were higher while reactance (Xc), phase angle, body cell mass (BCM), IGF-I, or IGF-I z-scores were lower than in normal responders (p<0.001). In all obese subjects, GH peak levels showed a negative correlation with age, BMI, waist circumference and FM, and a positive correlation with IGF-I. In the stepwise multiple linear regression, waist circumference and FM were the major determinants of GH peak levels and IGF-I. In conclusion, using the new cut-off limit of peak GH response to GHRH+ARG test for obese subjects, about 1/3 morbidly obese subjects were GHD. GHD subjects showed a significantly different body composition compared with normal responders, and the secretory defect was correlated to different anthropometric variables with waist circumference and FM as the major determinants.