All issues > Volume 38(10); 1995

Original Article

J Korean Pediatr Soc. 1995;38(10):1394-1403. Published online October 15, 1995.

Relationship of Insulin-like Growth Factor-I with Pharmacologically Stimulated Growth Hormone secretion in Growth hormone Deficient Children

Phil-Soo PS Oh¹, Ki-Joong KJ Kim¹, Young-Iee YI Yu¹, In-Joon IJ Seol¹, Jeh-Hoon JH Shin¹

¹Department of Pediatrics, College of Medicine, Hanyang University, Seoul. Korea

Abstract

Purpose
: At present, to determine growth hormone(GH) deficiency in short stature, many provocative tests using various pharmacologic agents such as clonodine, L-dopa, insulin should be done. These are not only complicated, but also misleading in some patients. And so, in search of a simple method of detecting GH deficiency that may replace the complicated stimulation test, we measured basal plasma insulin-like growth factor-I(IGF-I) to see the correlation with the peak GH levels in the stiumlation test. Methods : At the department of Pediatrics, Hanyang University Hospital from November, 1992 to February, 1994, we selected 32 GH deficiency-suspected children on the base of their growth data and bone age. After GH stimulation with clonidine(100-150 μg/m2) and L-dopa(200-250 mg/m2), we measured their peak GH levels by the immunoradiometric assay(IRMA) kit. The IGF-1 was separated from other plasma constituents with YMC-pack 300 SW column using high-performance liquid chromatography system and measured by the Nichols RIA kit. Results : 1) The mean IGF-I level of eight normal short stature(NSS) in Tanner stage I is 124.3±37.3ng/ml and their stimulated mean peak GH level is 18.7±7.5ng/ml. However, for one of the NSS in Tanner stage I with nutritional deficiency, the IFG-I level is 36.6ng/ml and the stimulated peak GH level is 12.2ng/ml. And, the mean IFG-I and peak GH levels of three Tanner stage II NSS are 253.3±78.4ng/ml and 12.9±4.3ng/ml, respectively. 2) The mean IFG-I level of five partial GH deficient(PGHD) children in Tanner stage I is 163.4±58.8ng/ml, and their stimulated mean peak GH level is 8.2±1.3ng/ml. The mean IGF-I level of five PGHDs in Tanner stage II is 194.6±77.3 ng/ml, and their stimulated mean peak GH level is 7.6±1.6ng/ml. And, one Tanner stage IV PGHD뭩 IGF-I level is 342.5ng/ml, and his stimulated peak GH level is 6.9ng/ml. 3) The mean IGF-I level of six complete GH deficient(CGHD) children in Tanner stage I is 24.5±10.1ng/ml, and their stimulated mean peadk GH level is 1.0±1.2ng/ml. However, two Tanner stage II CGHDs?IGF-I levels are 98.9, 201.5ng/ml and their stimulated peadk GH levels are 3.7, 2.9ng/ml, respectively. And, one Tanner stage III CGHD뭩 IGF-I level is 274.5ng/ml, and his stimulated peak GH level is 6.9ng/ml. Analyzing our data, we can find good relationship in stimulated peak GH level(Y) and basal IGF-I level(X) only between the Tanner stage I NSS and the Tanner stage I CGHD, that is to say, Y=0.13X+0.32, r=0.74, p<0.01 Conclusion : In the three different groups of short stature, IGF-I levels are not closely related. That is to say, IGF-I level changes according to the sexual maturation and nutritional status. However, excluding the PGHD and the factor of sexual maturation and nutritional staus, we can find good relationship between the IGF-I level and the stimulated peak GH level only in Tanner stage I children. And so, if we could carefully evalute their nutritional staus, at least we can use the basal plasma IGF-I level as a screening test of complete GH deficiency (cut-off level:below 50ng/ml) in the Tanner stage I short stature.

Keywords :IGF-I, Growth hormone deficiency, High-performance liquid chromamtography