S(G), S(I), and EGP of exercise-trained middle-aged XXXX estimated by a two-compartment labeled minimal model.

@entity1 @entity413
To examine the effects of physical training on @entity413 effectiveness (S(G)), insulin sensitivity (S(I)), and endogenous @entity413 production (EGP) in middle-aged @entity1 , stable-labeled frequently sampled intravenous @entity413 tolerance tests (FSIGTT) were performed on 11 exercise-trained middle-aged @entity1 and 12 age-matched sedentary @entity1 . The time course of EGP during the FSIGTT was estimated by nonparametric stochastic deconvolution. @entity413 uptake-specific indexes of @entity413 effectiveness (S(2*)(G) x 10(2): 0.81 +/- 0.08 vs. 0.60 +/- 0.05 dl. min(-1). kg(-1), P < 0.05) and insulin sensitivity [S(2*)(I) x 10(4): 24.59 +/- 2.98 vs. 11.89 +/- 2.36 dl. min(-1). (microU/ml)(-1). kg(-1), P < 0.01], which were analyzed using the two-compartment minimal model, were significantly greater in the trained group than in the sedentary group. Plasma clearance rate (PCR) of @entity413 was consistently greater in the trained @entity1 than in sedentary @entity1 throughout FSIGTT. Compared with sedentary controls, EGP of trained middle-aged @entity1 was higher before @entity413 load. The EGP of the two groups was similarly suppressed by approximately 70% within 10 min, followed by an additional suppression after insulin infusion. EGP returned to basal level at approximately 60 min in the trained @entity1 and at 100 min in the controls, followed by its overshoot, which was significantly greater in the trained @entity1 than in the controls. In addition, basal EGP was positively correlated with S(2*)(G) . The higher basal EGP and greater EGP overshoot in trained middle-aged @entity1 appear to compensate for the increased insulin-independent (S(2*)(G)) and -dependent (S(2*)(I)) @entity413 uptake to maintain @entity413 homeostasis.
