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Abstract
Adiponectin exists in the blood as 3 forms, which are a trimer, a hexamer, and a high –molecular weight (HMW) form. We investigated
whether circulating HMW adiponectin levels were altered by oral glucose or fat ingestion. Forty male subjects underwent a 75-g oral
glucose loading test (OGTT), and 11 healthy subjects (5 women and 6 men) received a fat loading test. Serum levels of HMW and total
adiponectin were measured during the OGTT and the fat loading test. The fat loading test was performed for at least 8 hours. Among the
40 male subjects, 11 had normal glucose tolerance (NGT), 9 had impaired fasting glucose (IFG), 11 had impaired glucose tolerance, and
9 had diabetes mellitus (DM). In all 40 subjects, the serum total adiponectin level did not change significantly, whereas serum HMW
adiponectin decreased significantly after a glucose load and reached 92.2% of the basal level at 120 minutes after the OGTT ( P b.01). The
HMW to total adiponectin ratio decreased significantly from 0.47 ± 0.15 at baseline to 0.43 ± 0.13 at 120 minutes after a glucose load ( P b
.05). Serum HMWadiponectin measured at 120 minutes after the OGTT decreased significantly to 86.0% and 85.6% of the basal level in
subjects with NGT or IFG, respectively (both P b .01). In subjects with impaired glucose tolerance or DM, however, serum HMW
adiponectin did not change. The area under the curve for insulin at 30 minutes after a glucose load during the OGTT was significantly
larger in subjects with NGT or IFG than in those with DM ( P b.05). In addition, the insulinogenic index (ΔI0-30/ΔG0-30) was significantly
higher in subjects with NGT or IFG than in those with DM ( P b .001). Percentage changes in serum HMW adiponectin of the baseline at
120 minutes correlated negatively with those in serum insulin ( r = −0.468, P = .0023), but not plasma glucose, of the baseline at
30 minutes in 40 subjects. On the other hand, serum triglycerides increased significantly after an oral fat load in 11 healthy subjects; but
neither serum total nor HMWadiponectin changed. In conclusion, serum HMWadiponectin (but not total adiponectin) decreased rapidly
after glucose loading in subjects with NGT or IFG; and the decrease of HMW adiponectin may be associated with an increase of serum
insulin at 30 minutes.
© 2009 Elsevier Inc. All rights reserved.
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