Dexamethasone fails to suppress hyperendorphinaemia of obese children.

In order to evaluate the origin of hyperendorphinaemia in obese patients, plasma B-endorphin (B-EP), B-lipotropin (B-LPH) and cortisol levels were measured in basal conditions and after overnight treatment with 1 mg of dexamethasone. Thirteen obese children (weight excess ranging from 44 to 100\%) and 10 normal weight controls were studied. Weight gain started in prepuberty and could not be explained by concurrent diseases. Hormone levels were measured by RIA, either directly in the plasma (cortisol) or after silicic acid extraction and Sephadex G-75 column chromatography (B-EP and B-LPH). Basal B-EP levels in the obese children (19.4 +/- 4.9 pmol/l, mean +/- SEM) were significantly higher than in the controls (7.8 +/- 1.2, P less than 0.01), whereas B-LPH and cortisol was within normal range. In the controls, post-dexamethasone morning and afternoon hormone levels were significantly suppressed. In the obese children, B-EP concentrations remained unaffected by the treatment (14.6 +/- 5.3 and 14.9 +/- 5.2 at 08.00 and 16.00 h, respectively), whereas both B-LPH and cortisol values were significantly decreased. These data demonstrate that a short-term dexamethasone treatment is unable to correct the increased B-EP levels which characterize obese children, whereas it is effective on B-LPH and cortisol concentrations. It can be concluded that circulating B-EP in this condition loses the control of CRH. However, the origin of hyperendorphinaemia in obese patients still remains to be investigated.