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Arosio M, Macchelli S, Rossi CM, Casati G, Biella 0, Faglia G, the Italian Multicenter Octreotide Study Group. Effects of treatment with octreotide in acromegalic patients—a multicenter Italian study. Eur J Endocrinol 1995:133:430–9. ISSN 0804–4643 Treatment of acromegaly is effective in reversing the reduced life-span of patients only when serum growth hormone (GH) concentrations are lowered to less than 2.5 μg/l. Usual treatments achieve this goal in no more than 50–60% of patients. The effects of octreotide were studied in a prospective, open label study with 68 acromegalic patients enrolled in 10 Italian centers. Octreotide was administered sc at a dose of 100 μg t.i.d. for 1 year. After 3 months of therapy, octreotide was effective in decreasing serum GH levels below 2.5 μg/l in 16 out of 64 acromegalic patients (25%). Fifteen of them had pretreatment GH levels below 25 μg/l. Insulin-like growth factor I (IGF-I) levels normalized in about 40% of patients. No further GH reduction was observed after 1 year of treatment. The presence of abnormal GH responses to thyrotropin-releasing hormone (TRH) and gonadotropin-releasing hormone was reduced from 54 to 24% and from 16 to 12%, respectively. Tumor shrinkage was observed in 50% of 26 non-irradiated patients after 12 months of treatment. Both basal and TRH-stimulated serum prolactin levels significantly decreased in the 11 hyperprolactinemic patients. Although serum thyrotropin, free triiodothyronine and free thyroxine concentrations were not modified, a significant reduction of thyrotropin response to TRH was observed in the 9th month of therapy. In non-diabetic patients, an increase of mean blood glucose levels without modifications of fasting morning concentrations was found. About one-quarter of the patients with overt diabetes mellitus had an impairment of their metabolic control. Main clinical symptoms of acromegaly improved in 70–80% of patients. An 18% decrease of low-density-lipoprotein cholesterol and unchanged high-densitylipoprotein cholesterol levels were observed in 35 patients studied. Triglyceride levels decreased in patients with hypertriglyceridemia pretreatment. Regarding side effects, gallstones were newly diagnosed in five patients, three patients dropped out because of severe diarrhea and two diabetic patients dropped out due to worsening of their metabolic control. In conclusion, octreotide is an effective treatment of acromegaly, mainly in patients with moderate elevation of serum GH levels. The drug has also been proved to positively affect dyslipidemia. Maura Arosio, Institute of Endocrine Sciences, Ospedale Maggiore IRCCS, Pad. Granelli, Via F Sforza 35, 20122 Milano, Italy

Summary A single administration of dexamethasone causes both an early stimulatory and a late inhibitory effect on GH secretion in normal subjects. OBJECTIVE We investigated the effects of a single administration of dexamethasone on basal and GH-releasing hormone-stimulated GH secretion in eight patients with active acromegaly. DESIGN On three different days the patients received 4 mg i.v. dexamethasone, 1 μg/kg body weight GH-releasing hormone 1-29, or matched placebos in different order. PATIENTS Eight subjects with active acromegaly, five of whom had not been treated previously, while the other three had received octreotide therapy which was stopped at least 7 days before testing. MEASUREMENTS Serum GH levels were measured in duplicate by a commercially available RIA kit. RESULTS Dexamethasone administration caused a significant decline of mean ± SE GH levels from 51.8 ± 13.8 to 30.0 ± 9.2 mU/l at 180 minutes, that was not influenced by placebo administration at 180 minutes. On the contrary, when GH-releasing hormone substituted placebo administration, GH levels increased from 34.0 ± 9.8 mU/l at 180 minutes to 56.0 ± 15.6 mU/l at 195 minutes. The GH increase was higher when GH-releasing hormone was given without dexamethasone pretreatment (from 52.4 ± 13.0 mU/l at 180 minutes to 86.4 ± 25.4 mU/l at 195 minutes). Analysis of the GH area under the curve confirmed the significant inhibition of GH secretion after dexamethasone administration and the significant reduction of the GH response to GH-releasing hormone in the study with dexamethasone pretreatment. CONCLUSIONS At variance with data in normal subjects, acute i.v. administration of dexamethasone inhibits basal GH secretion and partially suppresses the GH response to GH-releasing hormone in acromegaly. Both alterations in the regulatory mechanism of adenomatous cells and perturbations of hypothalamic regulatory influences, induced by the state of chronic GH hypersecretion, are likely explanations of the different response to dexamethasone.

OBJECTIVE: To investigate whether blunted adrenomedullary responsiveness to stimuli is a primary feature of human obesity in childhood and adolescence DESIGN: Comparison of plasma catecholamine response to caffeine in obese and lean subjects before and after puberty onset. SUBJECTS: Twelve lean prepubertal subjects (six males and six females), 15 prepubertal obese subjects (seven males and eight females), 12 pubertal lean subjects (six males and six females) and 24 pubertal obese subjects (12 males and 12 females) MEASUREMENTS: Plasma levels of Luteinizing hormone (LH), follicle-stimulating hormone (FSH), 17β-estradiol and testosterone were used to validate Tanner score. Systolic and diastolic blood pressure, pulse rate and plasma catecholamines before and after caffeine administration (4 mg/kg of ideal body weight). RESULTS: Caffeine administration significantly stimulated adrenaline release in all subjects studied. The incremental area of adrenaline response to caffeine, analysed by multiple comparison test, was lower in pubertal obese subjects with respect to other groups. CONCLUSIONS: At variance with what is observed in adulthood obesity, prepubertal obese subjects show an intact adrenomedullary response to caffeine.

The mechanism of action of the synthetic growth hormone (GH)releasing peptide hexarelin is not yet fully understood. Although a direct effect on pituitary cells has been demonstrated, the peptide is also active at hypothalamic level, where specific binding sites have been found. The observation that hexarelin acts synergistically with GH-releasing hormone (GHRH) in releasing GH has suggested that it might suppress endogenous somatostatin secretion. As somatostatin is also inhibitory on TSH secretion, to verify the occurrence of modifications of the somatostatinergic tone induced by hexarelin, we studied its effects on TRH-induced TSH secretion. Seven normal subjects (4 women and 3 men aged 24-29 years) underwent the following tests on 3 different days: a) TRH (200 micrograms/l i.v.) + placebo; b) hexarelin (1 microgram/Kg bw i.v.) + placebo c) combined TRH + hexarelin administration. Hexarelin induced significant and similar increases in serum GH levels when given in combination either with placebo or with TRH (1217 +/- 470 vs 986 +/- 208 micrograms/min/l p:NS), while no modifications of GH levels were seen after TRH + placebo. Serum TSH levels were unmodified by hexarelin + placebo injection. The TSH increase elicited by hexarelin + TRH was superimposable to that elicited by TRH + placebo (1124 +/- 530 and 1273 +/- 380 mU/min/l respectively). Circulating PRL levels slightly increased after hexarelin + placebo too (897 micrograms/min/l), and the PRL response to hexarelin + TRH was slightly, although not significantly, greater than that observed after TRH + placebo (2680 +/- 1517 and 2243 +/- 1108 micrograms/min/l, respectively). In conclusion, our data show that hexarelin does not alter basal and TRH-stimulated TSH secretion, thus suggesting that it does not inhibit somatostatin release. Furthermore a modest PRL-releasing effect of this peptide has been confirmed.

Cabergoline (Cab), a very potent and long-lasting dopaminergic compound, was administered to 26 women with pituitary microprolactinoma [mean serum PRL levels: 124.8 +/- 11.3 micrograms/l (+/- SE), range 62-300 micrograms/l] and 3 patients with GH-secreting pituitary adenoma (2 with associated PRL hypersecretion) for 12 and 24 months, respectively. In microprolactinomas, a stable normoprolactinemia was achieved in 96.1% of cases: in 13 women (50%) with the lowest dose of the drug (0.5 mg/week), and in other 12 patients (46.1%) with increasing doses up to 3 mg/week. All the oligomenorrheic/amenorrheic women, except one, restored regular and ovulatory menses. Two patients became pregnant. Pituitary abnormalities at high resolution-CT (HR-CT) scan disappeared in 13 of 19 patients (68.4%) after 12 months of therapy and this feature persisted in 8/13 cases (61.5%) 12 months after drug withdrawal. During Cab discontinuation (range: 3-60 months), mean serum PRL levels remained significantly lower than the basal ones. Six of 25 women are still without therapy. In 2 patients, normoprolactinemia persisted up to 38 and 60 months, respectively. Cab treatment was re-instituted in 13 patients because of the recurrence of hyperprolactinemia. Five patients were lost at follow up. In all the acromegalic patients, Cab (1-3 mg/week) normalized serum GH, IGF-I and PRL levels. A clear improvement in clinical symptoms was observed in all patients, but neuroradiological improvement in only one. Cab therapy was very well tolerated, as only seven patients complained of mild and transient side-effects and none had to stop treatment. In conclusion, Cab is an effective, safe, and well tolerated dopaminergic compound for the treatment of hyperprolactinemic disorders and the control of the clinical and hormonal features of dopamine-sensitive acromegalic patients.

Treatment of acromegaly is effective in reversing the reduced life-span of patients only when serum growth hormone (GH) concentrations are lowered to less than 2.5 micrograms/l. Usual treatments achieve this goal in no more than 50-60% of patients. The effects of octreotide were studied in a prospective, open label study with 68 acromegalic patients enrolled in 10 Italian centers. Octreotide was administered sc at a dose of 100 micrograms t.i.d. for 1 year. After 3 months of therapy, octreotide was effective in decreasing serum GH levels below 2.5 micrograms/l in 16 out of 64 acromegalic patients (25%). Fifteen of them had pretreatment GH levels below 25 micrograms/l. Insulin-like growth factor I (IGF-I) levels normalized in about 40% of patients. No further GH reduction was observed after 1 year of treatment. The presence of abnormal GH responses to thyrotropin-releasing hormone (TRH) and gonadotropin-releasing hormone was reduced from 54 to 24% and from 16 to 12%, respectively. Tumor shrinkage was observed in 50% of 26 non-irradiated patients after 12 months of treatment. Both basal and TRH-stimulated serum prolactin levels significantly decreased in the 11 hyperprolactinemic patients. Although serum thyrotropin, free triiodothyronine and free thyroxine concentrations were not modified, a significant reduction of thyrotropin response to TRH was observed in the 9th month of therapy. In non-diabetic patients, an increase of mean blood glucose levels without modifications of fasting morning concentrations was found. About one-quarter of the patients with overt diabetes mellitus had an impairment of their metabolic control. Main clinical symptoms of acromegaly improved in 70-80% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum bone Gla protein (BGP), marker of osteoblastic function, carboxyterminal cross-linked telopeptide of type I collagen (ICTP), index of bone resorption, and aminoterminal propeptide of type III procollagen, marker of collagen synthesis, were evaluated in children with GH deficiency (GHD), in adults with childhood-onset GHD and in adults with acquired GHD in adultlife. In children with GHD, serum BGP (12.7 +/- 0.5 ng/ml), ICTP (8.5 +/- 0.9 ng/ml) and PIIINP (3.4 +/- 0.4 ng/ml) were significantly lower (p0.0001, p0.0001 and p0.001, respectively) than those observed in a sex and age matched control group (BGP:18.9 +/- 0.9 ng/ml, ICTP: 14.4 +/- 0.6 ng/ml, PIIINP: 6.7 +/- 0.7 ng/ml). In adults with childhood onsed GHD, BGP levels (3.7 +/- 0.4 ng/ml) were significantly lower (p0.0001) than those recorded in a sex and age matched control group (5.4 +/- 0.1 ng/ml), while ICTP (4.7 +/- 0.7 ng/ml) and PIIINP (3.7 +/- 0.5 ng/ml) levels were similar to those found in controls (ICTP: 4.1 +/- 0.3 ng/ml; PIIINP: 3.3 +/- 0.2 ng/ml). In adults with acquired GHD, serum BGP (5.3 +/- 0.4 ng/ml), ICTP (3.8 +/- 0.4 ng/ml) and PIIINP (3.6 +/- 0.3 ng/ml) levels were not significantly different from those recorded in controls (BGP: 5.4 +/- 0.1 ng/ml, ICTP: 4.1 +/- 0.3 ng/ml, PIIINP: 3.3 +/- 0.2 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)