Serum insulin-releasing activity and the Prader-Willi syndrome.

Pathogenesis and etiology of the various clinical features of the Prader-Willi syndrome (PWS) are not completely understood. There is evidence suggesting a hypothalamic abnormality leading to hypogonadism in this syndrome. To test the possible hypothalamic involvement in the pathogenesis of obesity in these patients we studied the sera of 5 patients with PWS for insulin-releasing activity of possible hypothalamic origin. In addition 4 patients with a PWS-like syndrome and 6 obese patients with signs of central nervous system damage were studied. All five patients with PWS showed significant insulin-releasing activity in their sera. Of the four patients with PWS-like symptoms three showed similar activity while three of the obese patients with central nervous system damage had this activity in their sera. Serum insulin-releasing activity has been shown earlier to be associated with childhood obesity and it could play a role in the pathogenesis of obesity in PWS.