Yokoya S, Suwa S, Maesaka H, Tanaka T
Department of Pediatrics, Kanagawa Children's Medical Center, Yokohama, Japan.
Pediatr Res. 1988 Feb;23(2):151-4. doi: 10.1203/00006450-198802000-00002.
Using antibodies to somatomedin C/insulin-like growth factor I (SmC) produced in rabbits using the recombinant hormone, we have developed a radioimmunoassay for SmC. Gel-chromatography of urine revealed that the vast majority of immunoreactive SmC was eluted coincident with 125I-SmC and a small portion eluted with fractions having a mol. wt. range of 30,000-40,000. The SmC concentration in urine was determined by radioimmunoassay after ammonium sulfate extraction. Values did not ordinarily exceed 1 ng/ml. When the values from normal subjects were expressed as ng/mg creatinine, high levels were observed in the neonatal period. These values fell rapidly in infancy, declined more gradually in childhood, were slightly elevated at early puberty, and were lowest in adulthood. Urine SmC concentrations in 15 pituitary dwarfs were lower than the averages obtained from agematched control subjects, and six of them showed abnormally low values. Three patients with active acromegaly had high SmC values in urine. In conclusion, 1) SmC, mainly of monomeric form, was immunologically detected in urine. 2) Radioimmunoassay for urine SmC revealed that values varied considerably with age in normal subjects and were partially dependent on the human growth hormone status. However, the full meaning of the findings remains to be elucidated.
利用重组生长激素在兔体内产生的抗生长调节素C/胰岛素样生长因子I（SmC）抗体，我们开发了一种SmC放射免疫分析法。尿液的凝胶色谱分析显示，绝大多数免疫反应性SmC与125I-SmC同时洗脱，一小部分与分子量范围为30,000-40,000的级分一起洗脱。硫酸铵提取后，通过放射免疫分析法测定尿液中的SmC浓度。数值通常不超过1 ng/ml。当将正常受试者的值表示为ng/mg肌酐时，在新生儿期观察到高水平。这些值在婴儿期迅速下降，在儿童期下降较为缓慢，在青春期早期略有升高，在成年期最低。15名垂体性侏儒症患者的尿液SmC浓度低于年龄匹配的对照受试者的平均值，其中6人显示出异常低值。3例活动性肢端肥大症患者尿液中SmC值较高。总之，1）尿液中可通过免疫方法检测到主要为单体形式的SmC。2）尿液SmC的放射免疫分析显示，正常受试者的值随年龄有很大差异，部分取决于人生长激素状态。然而，这些发现的全部意义仍有待阐明。
