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M Doknic, S Pekic, M Zarkovic, M Medic-Stojanoska, C Dieguez, F Casanueva and V Popovic

OBJECTIVE: It has recently been shown that increased body weight is associated with prolactinomas and that weight loss occurs with normalization of prolactin levels. On the other hand, decreased dopaminergic tone in humans is well correlated with obesity. The objective of this study was to correlate changes in prolactin levels with leptin and body mass index (BMI) in patients with prolactinomas treated with the long-acting dopamine agonist bromocriptine (BC). METHODS: Eleven female and twelve male patients, aged 36.7+/-2.6 years with BMI in males of 30.4+/-1.7 kg/m(2) and in females of 24.4+/-1.2 kg/m(2), were evaluated after 1 and 6 months and 11 patients were further evaluated after 2 years of BC therapy. Plasma prolactin is presented as the mean of four samples taken daily. Serum leptin was determined in the pooled serum from three samples taken at 15-min intervals at 0800 h after an overnight fast. Multivariate linear regression and repeated measures analysis of covariance were used. RESULTS: In males, pretreatment prolactin levels were 71 362+/-29 912 mU/l while leptin levels were 14.9+/-1.8 microg/l. In females, pretreatment prolactin levels were 11 395+/-5839 mU/l and leptin levels were 16.7+/-2.5 microg/l. The sexual dimorphism of serum leptin levels at initial presentation was preserved after adjusting for BMI and prolactin-induced hypogonadism. After 1 month of therapy, prolactin levels significantly decreased (males: 17 618+/-8736 mU/l, females: 3686+/-2231; P<0.05), BMI did not change (males: 30.2+/-1.7 kg/m(2), females: 24.1+/-1.2 kg/m(2); P>0.05), while serum leptin levels decreased (males: 12.5+/-1.5 microg/l, females: 13.6+/-2.1 microg/l; P<0.05). After 6 months of treatment, prolactin further decreased (males: 3456+/-2101 mU/l, females: 677+/-360 mU/l; P<0.05) as did BMI (males: 28.6+/-1.6 kg/m(2), females 23.1+/-1.0 kg/m(2); P<0.05). The difference was more pronounced in male patients. Leptin levels were 12.8+/-2.8 microg/l in males and 12.9+/-1.8 microg/l in females (P<0.05). After 2 years of BC treatment, prolactin levels were near normal (males: 665+/-439 mU/l, females 447+/-130 mU/l; P<0.05) and BMI remained 26.5+/-1.9 kg/m(2) for males and 23.6+/-0.8 kg/m(2) for females (P<0.05). Leptin levels were 9.5+/-2.2 microg/l in males and 18.7+/-3.1 microg/l in females (P<0.05). There was a gradual increase in the gender difference in serum leptin levels over time. Changes in serum leptin levels significantly correlated with changes in BMI (r=0.844, P<0.001) but did not correlate with changes in plasma prolactin levels after 1 month (r=0.166), 6 months (r=0.313) and 2 years (r=0.234, P>0.05). CONCLUSION: The long-acting dopamine agonist BC, by increasing dopaminergic tone, may influence body weight and likely body composition by mechanisms in addition to reducing hyperprolactinemia in patients with prolactinomas.

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S Pekic, M Doknic, D Miljic, M Joksimovic, J Glodic, M Djurovic, C Dieguez, F Casanueva and V Popovic

Objective: Posttreatment assessment of disease activity and definition of cure of acromegaly, using measurement of GH secretion, remains problematic. Furthermore, with our efforts to achieve tight biochemical control of the disease it is foreseeable that a proportion of patients may be rendered GH deficient, thus requiring testing for GH deficiency. The aim of our study was to evaluate residual GH secretion in cured patients with acromegaly.

Design and methods: At baseline, circulating GH, IGF-I, IGFBP-3, leptin and lipid (cholesterol and tri-glycerides) levels were measured in 33 acromegalic patients nine years after treatment with surgery of whom 6 were additionally irradiated. Two tests were performed: the GH suppression test - oral glucose tolerance test (OGTT) and the GH provocation test - ghrelin test (1 μg/kg i.v. bolus) and the results were compared with 11 age- and sex-matched control subjects.

Results: According to the consensus criteria (normal IGF-I levels and post-OGTT GH nadir <1 μg/l), 21 treated acromegalic patients were cured, 6 had discordant IGF-I and GH nadir values during OGTT, while 6 had persistent acromegaly. After the GH provocative test with ghrelin (cut-off for severe GH deficiency is GH <3 μg/l), we detected 9 severely GH deficient patients (GHD) among 21 cured acromegalic patients. Mean GH peak (±s.e.m.) response to the ghrelin test in GHD acromegalics was significantly lower compared with acromegalics with sufficient GH secretory capacity and control subjects (1.2 ± 0.2 μg/l vs 20.1 ± 2.4 μg/l vs 31.1 ± 2.5 μg/l respectively, P<0.0001). Mean IGF-I and IGFBP-3 levels were not different between GHD and GH-sufficient cured acromegalics. Leptin levels and body mass index (BMI) were significantly higher in GHD male acromegalics compared with GH-sufficient male acromegalics. GHD female acromegalics tended to have higher BMIs while leptin levels were not different.

Conclusions: The assessment of residual GH secretory capacity by the GH provocation test is necessary in the long-term follow-up of successfully treated acromegalics since a large proportion of these patients are rendered GH deficient.

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V Popovic, M Svetel, M Djurovic, S Petrovic, M Doknic, S Pekic, D Miljic, N Milic, J Glodic, C Dieguez, FF Casanueva and V Kostic

OBJECTIVE: In addition to neurological impairment, weight loss is a prominent characteristic of Huntington's disease (HD). Neuropathologically, the disease affects the caudate nucleus and the cerebral cortex, and also the hypothalamus. The recently discovered orexigenic hormone of gastric origin, ghrelin and the adipocyte hormone leptin, are two peripherally produced hormones exerting opposite effects on specific populations of hypothalamic neurons that play a key role in regulating energy intake and energy output. The aim of this study was to investigate the possible involvement of cerebrospinal fluid (CSF) and circulating ghrelin and leptin in the regulation of energy balance in patients with HD. METHODS: Twenty healthy normal-weight subjects undergoing orthopedic surgery, and fifteen patients with genetically verified HD, were enrolled in this study. The unified Huntington's disease rating scale (UHDRS) was used to assess clinical course of the disease. Blood samples for hormonal measurements were obtained by venipuncture and in-parallel CSF samples for leptin/ghrelin determination were obtained by lumbar puncture. RESULTS: Patients with HD had increased concentrations of ghrelin in plasma compared with healthy subjects (4523.7+/-563.9 vs 2781.1+/-306.2 pg/ml, P<0.01). On the other hand, patients with HD had decreased concentrations of leptin in plasma compared with healthy subjects (4.8+/-1.6 vs 10.9+/-2.4 ng/ml, P<0.01). The concentrations of CSF ghrelin and CSF leptin were equivalent to values in healthy subjects. No correlation was found between disease duration--and other clinical features of HD--and plasma or CSF leptin/ghrelin levels. In patients with HD, baseline levels of GH, IGF-I, insulin and glucose did not differ from those in healthy subjects. CONCLUSION: High circulating ghrelin and low leptin levels in patients with HD suggest a state of negative energy balance. Early nutritional support of patients with HD is advocated since patients with HD and higher body mass index at presentation have slower progression of the disease.