Effects of Age, Sex and Renal Function on Urinary Insulin-Like Growth Factor I(IGF-I) Levels in Adults.
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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±112.9ng/day and 167.8±73.2ng/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 24h urine when they were corrected by urinary Cr. IGF-I values in early morning urine were ranged from 60 to 1, 100ng/gCr with a mean value of 309.6ng/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 24h Cr clearance (CCr) and positively with urinary β<SUB>2</SUB>-microglobulin (β<SUB>2</SUB>-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.
- Endocrinologia Japonica
Endocrinologia Japonica 39(5), 507-515, 1992
The Japan Endocrine Society