Adiponectin - A possible factor in the pathogenesis of carbohydrate metabolism disturbances in patients with pheochromocytoma

Glucose metabolism disturbances are relatively common feature in pheochromocytoma patients. Decreased insulin secretion due to the inhibitory effect of supraphysiological plasma catecholamine concentrations was considered to be the main cause for pheochromocytoma-associated diabetes mellitus. However, data from animal and clinical studies have suggested that catecholamines can induce insulin resistance. More recent trials support the hypothesis that catecholamines inhibit adiponectin secretion. Objective: The aim of the present study was to evaluate the relationship between adiponectin levels and insulin sensitivity in patients with endocrine hypertension due to pheochromocytoma comparing them to these in patients with essential hypertension and healthy subjects. Design and methods: Three groups of subjects were enrolled in the study: 26 patients with pheochromocytoma, 30 normal-weight patients with essential hypertension and 31 healthy subjects. Adiponectin levels were determined by radioimmunoassay (RIA). Results: Serum adiponectin concentrations were significantly lower in patients with pheochromocytoma compared to these in normal-weight hypertensive patients and healthy controls. Postoperative adiponectin levels were significantly higher then preoperative despite of the increased BMI in pheochromocytoma patients. There was a significant negative correlation between adiponectin serum concentrations and preprandial glucose, insulin levels and HOMA as a marker of insulin sensitivity. In contrast to previous studies, we did not find a significant difference between circulating adiponectin levels in normal-weight patients with EH and healthy subjects. Conclusions: Hypoadiponectinemia in pheochromocytoma patients may represent a possible pathogenic factor for the development of carbohydrate metabolism disturbances in these patients. (C) 2010 Elsevier Ltd. All rights reserved.