title: The serum level of soluble CD26/dipeptidyl peptidase 4 increases in response to acute hyperglycemia after an oral glucose load in healthy subjects: association with high-molecular weight adiponectin and hepatic enzymes.
abstract: A soluble form of CD26/dipeptidyl peptidase 4 (sCD26/DPP4) is found in serum and it has DPP4 enzymatic activity. We investigated whether the serum level of sCD26/DPP4 was influenced by the oral glucose tolerance test (OGTT) in healthy subjects. The serum sCD26/DPP4 level increased significantly from 824.5 ng/mL (interquartile range, from 699.0 to 1050 ng/mL) at baseline to a peak of 985.0 ng/mL (interquartile range, from 796.5 to 1215 ng/mL) during the OGTT (P < 0.0001). The peak sCD26/DPP4 level correlated positively with the baseline age and body mass index, and fasting plasma glucose (FPG), homeostasis model assessment of insulin resistance (HOMA-IR), triglycerides (TG), alanine aminotransferase, and γ-glutamyl transpeptidase (GGT) levels whereas it correlated negatively with high-density lipoprotein (HDL) cholesterol and the serum levels of total and high-molecular weight (HMW) adiponectin. Stepwise regression analysis was done with forward selection of variables, including age, FPG, HOMA-IR, TG, HDL cholesterol, uric acid, GGT, C-reactive protein, and HMW adiponectin. In a model that explained 57.5% of the variation of the peak sCD26/DPP4 level, GGT (β = 0.382, P = 0.007) and HOMA-IR (β = 0.307, P = 0.034) were independent determinants of the peak serum level of sCD26/DPP4. Serum HMW adiponectin decreased significantly from 4.43 μg/mL (interquartile range, from 2.80 to 6.65 μg/mL) at baseline to 4.17 μg/mL (interquartile range, from 2.48 to 6.96 μg/mL) 120 minutes after the oral glucose load (P < 0.0001). The baseline serum level of sCD26/DPP4 showed a significant negative correlation with the percent change of HMW adiponectin during the OGTT. In conclusion, the serum level of sCD26/DPP4 increased acutely after an oral glucose load in apparently healthy subjects. The abrupt increase of serum sCD26/DPP4 after a glucose load may be a marker of insulin resistance that could come from liver or muscle.
authors.affiliation: Department of Endocrinology and Metabolism, Dokkyo Medical University, Mibu, Tochigi, Japan. Electronic address: yaso@dokkyomed.ac.jp.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Aso
authors.forename: Tomoko
authors.initials: T
authors.lastname: Terasawa
authors.forename: Kanako
authors.initials: K
authors.lastname: Kato
authors.forename: Teruo
authors.initials: T
authors.lastname: Jojima
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Suzuki
authors.forename: Toshie
authors.initials: T
authors.lastname: Iijima
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kawagoe
authors.forename: Shigeru
authors.initials: S
authors.lastname: Mikami
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Kubota
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Inukai
authors.forename: Kikuo
authors.initials: K
authors.lastname: Kasai
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D018819:Dipeptidyl Peptidase 4 / Q000097:blood*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D006943:Hyperglycemia / Q000097:blood* / Q000201:enzymology; D007700:Kinetics; D016014:Linear Models; D008099:Liver / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D012995:Solubility
chemical_list: D052242:Adiponectin; D001786:Blood Glucose; D018819:Dipeptidyl Peptidase 4
keywords: ALT; BMI; DPP4; ELISA; FGP; GGT; GIP; GLP; HDL; HMW; HOMA-IR; IFG; IGT; NAFLD; NASH; NGT; OGTT; PG; TG; alanine transaminase; body mass index; dipeptidyl peptidase 4; enzyme-linked immunosorbent assay; fasting plasma glucose; glucagonlike peptide; glucose-dependent insulinotropic polypeptide; high molecular weight; high-density lipoprotein; homeostasis model assessment of insulin resistance; impaired fasting glucose; impaired glucose tolerance; nonalcoholic fatty liver disease; nonalcoholic steatohepatitis; normal glucose tolerance; oral glucose tolerance test; plasma glucose; sCD26; soluble CD26; triglyceride; γ-glutamyl transpeptidase