MEASUREMENT OF EXCESSIVE APPETITE AND METABOLIC CHANGES IN PRADER-WILLI-SYNDROME

The behavioural, cognitive and metabolic response to food intake was s tudied in 13 adults with the Prader-Willi syndrome (PWS) and compared to ten age-matched controls. Rates of eating were observed during one hour's access to food and feelings of hunger were assessed using a vis ual analogue scale. Blood was taken for estimation of glucose, insulin , cholecystokinin (CCK), prolactin, growth hormone (GH) and cortisol e very 20min for a total period of 100min. Ten (76%) of the subjects wit h PWS ate steadily for the whole hour that food was available and on a verage consumed three times more calories than the control group. The median ratings for feelings of hunger in the PWS group changed in the expected direction but these changes were delayed compared to the cont rol group and only reached the same level as the controls after the PW S subjects had eaten a significantly greater amount of food. In the PW S group, in contrast to the control group, feelings of hunger started to re-emerge shortly after food was removed. There were marked differe nces between individuals with PWS in the extent of the changes in seru m prolactin levels. Increases in plasma glucose levels were inversely correlated with changes in hunger ratings in the PWS group, but not th e control group. There was a significantly greater increase in serum C CK levels during the meal in the PWS group than in the control group i ndicating that in PWS failure of peripheral release of CCK in response to food intake was not the explanation for the impaired satiety respo nse.