title: Urinary N-acetyl-β-D-glucosaminidase levels are positively correlated with 2-hr plasma glucose levels during oral glucose tolerance testing in prediabetes.
abstract: BACKGROUND
  Urinary N-acetyl-β-D-glucosaminidase (NAG) excretion is increased in patients with impaired glucose tolerance (IGT). This study investigated when during the oral glucose tolerance test (OGTT) the plasma glucose, urine glucose, and insulin levels correlate most strongly with urinary N-acetyl-β-d-glucosaminidase (NAG) levels in prediabetic subjects.
  
  
  METHODS
  The OGTT was administered to 80 subjects who had not yet received a diagnosis of diabetes mellitus (DM) and in whom HbA1c levels were ≤6.8% and fasting plasma glucose levels were <7.0 mmol/l. Forty-two subjects had normal glucose tolerance (NGT), 31 had impaired glucose tolerance (IGT), and 7 had DM according to World Health Organization criteria. Serum levels of cystatin C, the estimated glomerular filtration rate, the urinary albumin-to-creatinine (Cr) ratio, urinary and serum β2-microglobulin, and urinary NAG were measured as markers of renal function.
  
  
  RESULTS
  NAG levels were significantly higher in subjects with DM and in subjects with IGT than in subjects with NGT. No significant associations were observed between glycemic status and other markers of renal function. Multiple linear regression analysis showed that the NAG level was positively correlated with plasma glucose levels at 120 min of the OGTT and was associated with the glycemic status of prediabetic patients.
  
  
  CONCLUSIONS
  These results suggest that postprandial hyperglycemia is an independent factor that causes renal tubular damage in prediabetes patients.
authors.affiliation: Department of Internal Medicine (Divisions of Cardiology, Hepatology, Geriatrics, and Integrated Medicine), Nippon Medical School, Tokyo, Japan. otoshi@nms.ac.jp
authors.forename: Motoshi
authors.initials: M
authors.lastname: Ouchi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Suzuki
authors.forename: Masao
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Masayuki
authors.initials: M
authors.lastname: Motoyama
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohara
authors.forename: Kazunari
authors.initials: K
authors.lastname: Suzuki
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Igari
authors.forename: Kentaro
authors.initials: K
authors.lastname: Watanabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakano
authors.forename: Kenzo
authors.initials: K
authors.lastname: Oba
mesh_terms: D000118:Acetylglucosaminidase / Q000652:urine*; D000293:Adolescent; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D055316:Cystatin C / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011236:Prediabetic State / Q000097:blood* / Q000652:urine*; D018709:Statistics, Nonparametric
chemical_list: D000118:Acetylglucosaminidase; D001786:Blood Glucose; D055316:Cystatin C; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human