Lack of leptin suppression in response to hypersecretion of catecholaminesin pheochromocytoma patients

Leptin is a major regulator of body weight and energy balance and is subjec t to a variety of regulatory inputs. From several previous studies, catecho lamines have been suggested to exert an inhibitory influence on leptin prod uction in animals. In the present study, we analyzed leptin levels in relat ion to catecholamine hypersecretion in 27 human pheochromocytoma patients. A 10-fold increase in circulating norepinephrine (P < .0001) did not result in suppression of plasma leptin in the patients compared with normal contr ols (median and interquartile range, 4.3 ng/mL [2.4 to 6.8] v 2.2 ng/mL [1. 9 to 3.0] in men and 18.6 [12.3 to 27.0] v 11.4 [10.1 to 15.9] in women). C orrelation analysis indicated a significant association of leptin with epin ephrine in normal subjects (r = -.81, P < .0001), but not in pheochromocyto ma patients. Leptin was not related to norepinephrine in either group. In c onclusion, our data suggest that a chronic elevation of catecholamines does not cause suppression of leptin secretion in patients with pheochromocytom a. This lack of effect may be attributable to the development of tolerance of adipose tissue leptin production to catecholamines. Copyright (C) 1999 b y W.B. Saunders Company.