Pubertal adolescent male-female differences in insulin sensitivity and glucose effectiveness determined by the one compartment minimal model

Most studies of insulin sensitivity in puberty have been cross-sectional an d have not been able to longitudinally address changes that might occur. In addition, these studies were unable to separate out glucose's ability to s timulate its own disposal (glucose effectiveness, S-G) from insulin sensiti vity (S-I) or to separate the hepatic and peripheral effects of insulin. To address these problems, we used the frequently sampled i.v. glucose tolera nce test with [6,6]D-2 glucose to study S-G* and S-I* in 24 children (Tanne r stage 1-3) at 6-mo intervals over an Ig-mo period.,Mean overnight GH and fasting GH binding protein (GHBP), IGF-I, and leptin levels were also measu red. S-G* did not differ between the sexes or Tanner stages. S-I* did not d iffer between Tanner stages for either se!: and was higher in boys than in girls. Hepatic insulin resistance did not differ between sexes or Tanner st ages. S-G* was not related to any of the other variables measured. S-I* was negatively related to BMI, GHBP, IGF1, and leptin. These results demonstra te that insulin sensitivity is greater in prepubertal and early pubertal bo ys than in girls and is primarily determined by body mass effects.