The impact of ghrelin on bone mineral density in boys : effect of biological maturation and physical activity

The aims of the present study were to: 1) assess the influence of regular phsyical activity on ghrelin concentration in prepubertal and pubertal boys; and 2) examine the impact of ghrelin and insulin like growth factor-I (IGF-I) concentrations on bene mineral density (BMD) in boys with different physical activity patterns at different pubertal stages. In total, 56 healthy schoolboys aged between 10 and 16 years were divided into the swimming (n=28) and the control (n=28) groups. The subjects were matched by age and body mass index (BMI) genrating 9 matches pairs in pubertal group I (Tanner stage 1), 11 pairs in group II (pubertal stages 2 & 3) and 8 pairs in group III (pubertal stages 4 & 5). To reduce the effect of body size on BMD vaues, apparent volumetric bone mineral density (BMAD) of the lumbar spine was calculated. Swimers in pubertal groups IIand III had significantly (both p < 0.05) higher mean plaslma ghrelin concentration than the control groups. In conclusion plasma ghrelin concentrations decreased durign puberty in physically inactive boys, while in regularly physically active boys it remained relatevely unchanged