Effects of age, sex and renal function on urinary insulin-like growth factor I (IGF-I) levels in adults.
Insulin-like growth factor I (IGF-I) levels in urine were measured in adults using specific RIA after extraction with acid-ammonium sulfate. Mean (+/- SD) total urine IGF-I values were 267.9 +/- 112.9 ng/day and 167.8 +/- 73.2 ng/g creatinine (Cr) in 17 normal young adults. There was a positive correlation (r = 0.785, P < 0.001) between IGF-I values in early morning urine and those of 24 h urine when they were corrected by urinary Cr. IGF-I values in early morning urine were ranged from 60 to 1,100 ng/gCr with a mean value of 309.6 ng/gCr in 178 normal adults aged 21-80 yr. There was a consistent trend towards higher urinary IGF-I values in males during aging and this trend did not reach statistical significance until the sixth and seventh decades. There was a positive correlation (r = 0.465, P < 0.005) between urinary IGF-I values and age in males but not in females. Although urinary IGF-I values were higher in females than in males of the second and third decades, no sex difference was found in older adults. Urinary IGF-I values were correlated reversely with 24 h Cr clearance (CCr) and positively with urinary beta 2-microglobulin (beta 2-MG) levels in patients with renal dysfunction. These findings indicate that urinary IGF-I levels are influenced by age, sex and renal function in adults.
Yamamoto
H
H
Department of Medicine, Shimane Medical University, Izumo, Japan.
Kato
Y
Y
D000328:Adult; D000367:Age Factors; D000368:Aged; D001806:Blood Urea Nitrogen; D002850:Chromatography, Gel; D003404:Creatinine / Q000378:metabolism; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000302:isolation & purification / Q000652:urine*; D007668:Kidney / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D012737:Sex Factors; D001613:beta 2-Microglobulin / Q000652:urine
D001613:beta 2-Microglobulin; D007334:Insulin-Like Growth Factor I; D003404:Creatinine