To study a potential alteration of hypothalamic centers involved in the negative feedback action of
leptin on
body weight, serum
leptin levels were measured in relation to BMI in 18 patients following surgery for a hypothalamic
craniopharyngioma (Ctx), and were compared to levels found in 21 patients operated for a
pituitary adenoma (Ptx) or in healthy control subjects. All subjects with Ptx received rhGH replacement
therapy (0.5 to 2 IU/m2/d), and serum
leptin levels were followed in 3 months intervals over 24 months. Serum
leptin levels in patients with Ptx were comparable to controls, whereas 7 of the 18 patients with Ctx had higher than expected concentrations for their BMI. GH treatment in Ptx subjects did not alter serum
leptin levels. In 5 Ctx patients where preoperative samples were available,
weight gain in parallel to an increase in serum
leptin levels was observed but only minimal changes in 4 others. Our data support the role of
leptin as an important marker of
body weight. The rapid increase in serum
leptin levels observed in some Ctx subjects suggests that early postoperative measurement of serum
leptin levels may help to identify patients at risk of
weight gain following hypothalamic destruction.