Normal linear growth in children is highly complex process, regulated by interaction of genetic, environmental and hormonal factors.
We present four growth hormone deficient patients which despite severe growth hormone deficiency according to the provocative tests (ITT or GHRH+GHRP-6) and decreased IGF I level grew normally. This study was approved by Ethical Committee of University Clinical Center Belgrade. Three of our patients had idiopathic multiple pituitary deficit (No. 1,3,4) while one patient (No. 2) was operated and irradiated due to glioma n. optici in childhood. All patients were on complete conventional hormonal replacement. In patients No. 1 and No. 3 MRI showed normal pituitary, patient No. 2 a tumor rest and huge frontal higroma while patient No. 4 had stalk disconnection on MRI. In patient No. 1 Prop 1 gene mutation was confirmed. We measured insulin and ghrelin levels during OGTT and leptin pool in all. Auxological and hormonal characteristics of our patients are presented in a Table.
|Sex and age (yrs)||Height (cm)||BMI (kg/m2)||OGTT-insulin peak (mU/l)||OGTT-ghrelin basal and through (pg/ml)||Leptin pool (ng/ml)||PRL (mU/l)|
|F; 22||177||30.7||166||1218; 1112||48||299|
|F; 24||178||24.0||129||937; 1039||27||292|
|M; 25||184||29.5||245||1042; 898||66||73|
|M; 26||181||28.7||93||482; 529||38||338|
Some studies speculate that insulin, leptin, PRL and ghrelin could play a role in linear growth without GH. Our patients showed hyperinsulinemia during OGTT which can act as growth stimulus. High leptin levels might contribute to linear growth. Although three patients were obese they did not show decreased ghrelin levels as in simple obese patients and nor suppression during OGTT. This report shows that other factors besides GH and IGF 1 have an important role in growth.
01 - 05 Apr 2006
European Society of Endocrinology