Resistin is an
adipokine that induces
insulin resistance in mice; serum concentrations are decreased by fasting and increased by feeding.
Adiponectin, another
adipokine, improves
insulin sensitivity. The aims of this study were to determine the effects of
glucose and meal loading on serum
resistin and total and high-molecular weight (HMW)
adiponectin in humans and to explore potential determinants of fasting serum
resistin and of changes in
resistin. Serum
resistin and total and HMW
adiponectin were measured by
enzyme-linked
immunosorbent assay in young, lean, nondiabetic subjects during 75-g oral
glucose tolerance test (OGTT) and meal tolerance test (MTT).
Resistin single nucleotide polymorphism (SNP) -420 was typed. Serum
resistin was decreased at 60 and 120 minutes during OGTT compared with baseline (n = 36, 1-way repeated-measures analysis of variance, P < .0001; Scheffe, P = .0457 and P < .0001, respectively). Serum
resistin was also reduced at 240 minutes during MTT (n = 33, 1-way repeated measures analysis of variance, P < .0001; Scheffe, P = .0002). Multiple regression analysis adjusted for age, sex, and body mass index revealed that the reductions in serum
resistin were dependent on baseline
resistin levels. Subjects with greater baseline concentrations of
resistin experienced more pronounced declines in
resistin (OGTT, unstandardized regression coefficient (beta) = -0.19, P = .0005; MTT, beta = -0.63, P < .0001). Serum total and HMW
adiponectin was unchanged. Fasting serum
resistin was positively correlated with the G allele number of SNP -420 (beta = 7.70, P = .01) and white blood cell count (beta = 0.007, P = .0001) adjusted for age, sex, and body mass index. Therefore, in young, lean, nondiabetic humans, serum
resistin was reduced by
glucose and meal loading; the reduction in
resistin was greater in subjects with higher fasting
resistin. Fasting
resistin was correlated with SNP -420 and white blood cell count.