Impaired satiety regulation in obese patients with craniopharyngioma

In patients suffering from craniopharyngioma (cp), a histologically benign tumor located in pituitary and hypothalamic regions, severe posttreatment obesity is a major problem. In the present study, we investigated the secretion of orexigenic hormone Ghrelin and satiety hormone PYY.

In 34 patients recruited in Kraniopharyngeom 2000, total Ghrelin and PYY serum levels were quantified before and one hour after intake of 400kcal of a standard liquid mixed meal by commercial RIAs. According to their BMI-SDS three groups were formed. Group 1: 7 patients with normal weight (BMI <2SDS); group 2: 4 obese patients (BMI: 2–3 SDS); group 3: 23 patients with severe obesity (BMI >3SDS). Basal Ghrelin levels were significantly higher in group 1, compared to 3 (p<0.01; mean basal Ghrelin group 1: 1,047, group 2: 785, and group 3: 669ng/ml). 1h after standard meal reduction of Ghrelin was in group 1 significantly stronger than in group 3 (p<0.05; δ Ghrelin group 1: –308, group 2: –95, and group 3: –81ng/ml). Basal PYY did not differ between the groups (group1: 264, group 2: 222, and group 3: 240ng/ml), and there were no significant differences in the increase of PYY after the meal (mean increase of PYY group 1: 82, group 2: 114, group 3: 48ng/ml).

These findings support the hypothesis of reduced Ghrelin secretion and reduced post-meal suppression in cp-patients suffering from severe obesity leading to disturbed regulation of appetite. PYY levels did not differ between normal weight, obese and very obese cp-patients.

Supported by Deutsche Kinderkrebsstiftung, Bonn