SERUM INSULIN-LIKE GROWTH-FACTOR-I (IGF-I) IN NORMAL JAPANESE ADULTS

To evaluate surgical and medical treatment of GH-producing pituitary t umors and GH supplement to GH-deficient patients, we determined the re ference values for serum IGF-I in Japanese adults. The serum IGF-I con centration in 454 apparently healthy subjects (246 men aged 21-70 year s and 208 women aged 21-72 years) was measured with a commercial RIA k it after acid-ethanol extraction. The concentration of serum IGF-I dec reased with age in both sexes. The IGF-I in females was significantly higher than that in males in the group aged 21-30 years and lower in t he group aged 61-72 years. We conclude that an age- or sex-related sta ndard is necessary for comparing IGF-I values in patients.