Influência da dexametasona e da perda ponderal na regulação dos níveis séricos de leptina em indivíduos obesos.

Influência da dexametasona e da perda ponderal na regulação dos níveis séricos de leptina em indivíduos obesos.

Alternative title Influence of dexamethasone and weight loss on the regulation of leptin serum levels in obese individuals
Author Lerário, Daniel Diniz Gonçalves Autor UNIFESP Google Scholar
Abstract The adipocyte honnone leptin is thought to serve as a signal to the central nervous system reflecting the status of fat stores. Serum levels of leptin and adipocyte leptin messenger RNA levels are clearly increased in obesity. Nevertheless, the factors regulating leptin production are not yet fully understood. Leptin serum levels can be changed by weight loss and some honnones like insulin and glucocortleoids also appear to be regulators of leptinemia independently of changes in body weight. The aim of this study was to determine the effects of in vivo administration of the synthetic glucocorticoid dexainethasone and weight loss on the serum levels of leptin. Twenty five obese subjects were studied (l8 females / 7 males) mean age 26,6 n 6ys, BMI 31,1 n 2,5 KgliW, por cento fat 40,3 n 8,3, compared at baseline to 22 healthy 'mdividuals. Serum levels of leptin, insulin, proinsulin and glucose were assessed at baseline and after ingestion of dexamethasone 4 mg per day (2mg, 2x daily)on two consecutive days. To study the effectsof weight loss on serum leptin, 17 of the obese subjects (I 2 women and 5 men) BMI 31,6 n 2,7 K g/M2 ; age 26,3 n 6 ys; por cento fat 40,7 n 8,15 were submltted to a low calorie dietary intervention trial for 8 weeks and again blood samples were collected. Plasma leptin levels were significantly higher in obeses when compared to the control group. A positive high correlation between leptinemia and the magnitude of fat mass was found (r--0,88; p<O,OOOl). After dexatnethasone there was a significant increase on leptin serum levels (22,9 n 12,3 vs 51,4 n 23,3 ng/n-d; p <O,05). Reduction of weight was significant after 8 weeks of hypocaloric diet (86,1 n 15,1 vs 80,6 n 14,2 Kg ; p<O,O5). A concomitant reduction on leptin levels was observed (25, 13 @ 12,8 vs 15,9 n 9,1 ng/ml ; p <O,05). We conclude that plasma leptin levels are primordially dependent on fat mass magnitude. Glucocorticoids are potent secretagogues of leptin in obeses. Mild fat mass reduction leads to an out of proportion decrease in leptin serum levels. This suggests that nutricional and honnone interactions also seem to play an important role on the regulation of leptin levels independently of changes in fat mass
Keywords Dexametasona
Perda de peso
Language Portuguese
Date 1999
Published in São Paulo: [s.n.], 1999. 76 p. ilus., tab.
Publisher Universidade Federal de São Paulo (UNIFESP)
Extent 76 p.
Access rights Closed access
Type Dissertation

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