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Measurement of serum 20K-hGH in children
GRS'98
0 - 2 5 A N I M M U N O F U N C T I O N A L GH ASSAY: USE IN CHILDREN
N Mauras ~, AD Rogol 2, P Walton 3. 1Nemours Children's Clinic, Jacksonville, FL; 2University of Virginia, Charlottesville, VA; 3Diagnostic System Laboratory, Webster, TX. An immunofunctional (IF) GH assay, developed by DSL, is based on the concept that GH dimerizes two GH receptors at two binding sites (JCEM 1996; 81:2613). A monoclonal antibody against binding site 2 of GH is immobilized in a well and incubated with sera containing GH; after a wash, rhGHBP is added which binds to binding site 1 and assay quantified using Streptavidin-HRP. To assess the correlation between this assay and a standard ELISA (DSJ2s GH1), and a Hybritech IRMA (GH2) 20 short children (mean age _+ SE:10.2 + 1.0 years) undergoing GH stimulation (Arginine/L-Dopa or Insulin) were recruited. Mean height SDS -2.33 _+0.43, Bone age: 9.0 _+ 1.0 years, BMI: 16.7 + 1.1 kg/mZ Table ( n = 15):
GH1
GH2
IGFI (ng/ml)
BP3 (mg/I)
ALS (#g/m[)
180+21
3.0+0.2
12.8+1.0
Mean 2.82+0.56
2.91_+0.53
4.69+0.82
Peak
5.99--1.02
10.25+1.68
5.87_+1.09
319
with GHD, nGHD, Turner syndrome and precocious puberty. In summary, the serum hGH includes about 6% of 20 K, and the percentage is not changed by sex, pubertal stage, or any of the diseases causing short stature.
IV P E D I A T R I C S
IFGH (ng/ml)
Abstracts
The correlation between mean and peak IFGH and GH1 was strong (ta = 0.901, P = 5.9 x 10 % slope of 0.966), and between IFGH and GH2, and GH2 and GH1, yet the GH2 levels were consistently higher (r~ = 0.963, P = 1.98 x 10 -64, slope = 0.622; r2 = 0.934, P = 4.64 x 10 49, slope = 0.622, respectively). There was no correlation between IFGH and BP3, ALS, Height SDS and age, although IFGH and IGF-1 (r2 = 0.217, P = 0.08) and BMI (r2 = 0.202, P = 0.09) approached significance. In summary: a novel IFGH assay correlates well with the GH measured by DSL's EUSA, and Hybritech's IRMA. The latter, however gives consistently high results in children with severe short stature, maybe due to detection of bioinactive forms of GH. In conclusion: further studies will allow us to assess if IFGH will aid the clinician to standardize GH stimulation test results by quantitating GH molecules capable of generating a biological signal. [Supported in part by DSI.] 0 - 2 6 M E A S U R E M E N T OF S E R U M 2 0 K-hGH I N C H I L D R E N
M Ishikawa 1, Y Hasegawa 2, Y Hashimoto 3 Tachibana 4, T Tanaka ~, E Tokuhiro s, T Yasuda ~, S Yokoya75 National Children's Med Res Ctr; 2 Kiyose Children's Hospital; 3Mitsui Pharmaceuticals, Inc.; 4 Kanagawa Children's Med Ctr; 5Odawara City Hospital; ~Chiba University; rToranomon Hospital. Twenty K-human GH (20 K) differs from the 22 K-human GH (22 K) by deletion of 15 amino acids, residues 32-46. Since serum 20 K has not been measured directly, the percentage of 20 K in human GH (hGH) has not been determined. We measured the serum 20 K and 22 K in normal children, patients with growth hormone deficiency (GHD), non-GHD short stature (nGHD), Turner syndrome, and precocious puberty. The 20 K and 22 K were measured by ELISA using anti-hGH monoclonal antibodies specific for 20 K or 22 K. The percentage of 20 K in hGH was calculated as the percentage of 20 K in the total of 20 K and 22 K. In normal boys and girls, mean serum 20 K was respectively 152 and 123 pg/ml, and mean serum 22 K was 2.4 and 2.1 ng/ml. The mean percentage of 20 K were 5.9 and 6.0%, respectively. There was no significant difference in the percentage of 20 K between boys and girls, between prepuberty and puberty. And also there was no significant difference in the percentage of 20 K between normal children and the patients
O-27 C O M P A R I S O N B E T W E E N IGF-I A N D GH IN PERINATAL G R O W T H
Z Laron, B Klinger, Schneider Children's Med. Ctr. Israel, Sackler Fac. Med., Tel Aviv Univ., Israel. We have investigated the growth pattern during the first 5 years of life in four patients (pts) (2 M, 2 F) with cong. Isolated growth hormone deficiency (IGHD = secondary IGF-I deficiency) and five pts (3 M, 2 F) with GH resistance (Laron Syndrome=LS=primary IGF-I deficiency). One pt was GHBP > and 4 GHBP Birth length ranged from 45-49 cm in both groups (from -2.5 to -4.5 SDS). Untreated LS pts progressively slowed their growth decreasing the height (ht) SDS from -3.5 to -6.5. IGF-I treatment (200 mg/kg/day s.c.) to three LS pts accelerated growth with a gain of 0.5 to 1.5 ht SDS in 2 years. During IGF-I treatment basal s.c. IGF-I rose from 3-6 to 7-20 nM/1 denoting optimal dosage. There was also a rise in serum procollagens. Untreated IGHD pts decreased ht SDS from -2.5 to 5.2 at 1 year and -5.7 at 2 years. Initiation of hGH treatment (0.07 U/kg/day) between ages 1-4 accelerated growth velocity with gain of 1.2 to 2.4 ht SDS in 3 years. All untreated babies had borderline or below normal head circumferences. Treatment by IGF-I or hGH induced a rapid catch-up of the head size, crossing normal limits within a half to 2 years. In the two untreated LS pts, head circumference remained below normal. Despite a similar birth length, infants with IGHD responded in their linear growth better to hGH than did infants with LS to IGF-I. The response of the brain growth was similar in both groups. Our observations suggest differential effects of hGH and IGF-I on growth. It seems that for optimal linear growth, IGF-I requires hGH either in a preparatory phase or for synergistic action. This is not the case for brain and other organ growth. Partial resistance to IGF-I cannot be excluded. 0 - 2 8 L O N G I T U D I N A L CHANGES I N G R O W T H H O R M O N E RELEASE, BODY COMPOSITION, A N D BODY FAT D I S T R I B U T I O N A R E INVERSELY RELATED IN C H I L D R E N A N D ADOLESCENTS
JN Roemmich ~, PA Clark ~, SS Berr z, VM Mai 2, A Weltman 3,4, AD Rogol ~,5, Departments of ~Pediatrics, 2Radiology, 3Education, 4Medicine, 5pharmacology, University of Virginia. We examined the relationships among 12-month changes in sex steroid levels and criterion measures of body composition [body density (underwater weighing) corrected for body water (deuterium dilution) and mineral (DEXA)], abdominal fat distribution [MRI for visceral fat (AVF) and subcutaneous fat (ASF)], subcutaneous fat distribution (sMnfolds) and GH release (ql0 min from 1800 h to 0600 h) in prepubertal and pubertal boys (n=l 1; n=9) and girls (n=9; n=12). At baseline, neither the area under the GH-time curve (AUC), the sum of the GH peak heights (sum GH pk hts), or the mean nadir GH level (GH nadir) were related to the adiposity variables. The 12-month change in AUC was inversely related to the change in sum of sMnfolds (r= -0.31, P = 0.05), fat mass (FM) (r= -0.45, P = 0.003), and ASF (r= -0.41, P = 0.02) but not the AVF (r= 0.11, P = 0.53) and directly related to the change in free-testosterone (r= 0.38, P = 0.03). The change in sum GH pk hts was inversely related to the change in the sum of limb sMnfolds (peripheral subcutaneous fat; r = -0.34, P = 0.03). The change in GH nadir was not significantly related to any adiposity or sex steroid variables. In stepwise regression, the change in FM and free-testosterone accounted for 28% of the variance for the change in AUC. We conclude that due to large inter-individual differences in GH release, cross-sectional studies may not adequately describe the relationship between adiposity and GH release in children and the various GH pulse attributes are influenced by different adiposity/fat distribution factors. [Funded by NIH HD 32631, GCRC RR00847, and the Genentech Foundation for Growth and Development.]
0 - 2 5 A N I M M U N O F U N C T I O N A L GH ASSAY: USE IN CHILDREN
N Mauras ~, AD Rogol 2, P Walton 3. 1Nemours Children's Clinic, Jacksonville, FL; 2University of Virginia, Charlottesville, VA; 3Diagnostic System Laboratory, Webster, TX. An immunofunctional (IF) GH assay, developed by DSL, is based on the concept that GH dimerizes two GH receptors at two binding sites (JCEM 1996; 81:2613). A monoclonal antibody against binding site 2 of GH is immobilized in a well and incubated with sera containing GH; after a wash, rhGHBP is added which binds to binding site 1 and assay quantified using Streptavidin-HRP. To assess the correlation between this assay and a standard ELISA (DSJ2s GH1), and a Hybritech IRMA (GH2) 20 short children (mean age _+ SE:10.2 + 1.0 years) undergoing GH stimulation (Arginine/L-Dopa or Insulin) were recruited. Mean height SDS -2.33 _+0.43, Bone age: 9.0 _+ 1.0 years, BMI: 16.7 + 1.1 kg/mZ Table ( n = 15):
GH1
GH2
IGFI (ng/ml)
BP3 (mg/I)
ALS (#g/m[)
180+21
3.0+0.2
12.8+1.0
Mean 2.82+0.56
2.91_+0.53
4.69+0.82
Peak
5.99--1.02
10.25+1.68
5.87_+1.09
319
with GHD, nGHD, Turner syndrome and precocious puberty. In summary, the serum hGH includes about 6% of 20 K, and the percentage is not changed by sex, pubertal stage, or any of the diseases causing short stature.
IV P E D I A T R I C S
IFGH (ng/ml)
Abstracts
The correlation between mean and peak IFGH and GH1 was strong (ta = 0.901, P = 5.9 x 10 % slope of 0.966), and between IFGH and GH2, and GH2 and GH1, yet the GH2 levels were consistently higher (r~ = 0.963, P = 1.98 x 10 -64, slope = 0.622; r2 = 0.934, P = 4.64 x 10 49, slope = 0.622, respectively). There was no correlation between IFGH and BP3, ALS, Height SDS and age, although IFGH and IGF-1 (r2 = 0.217, P = 0.08) and BMI (r2 = 0.202, P = 0.09) approached significance. In summary: a novel IFGH assay correlates well with the GH measured by DSL's EUSA, and Hybritech's IRMA. The latter, however gives consistently high results in children with severe short stature, maybe due to detection of bioinactive forms of GH. In conclusion: further studies will allow us to assess if IFGH will aid the clinician to standardize GH stimulation test results by quantitating GH molecules capable of generating a biological signal. [Supported in part by DSI.] 0 - 2 6 M E A S U R E M E N T OF S E R U M 2 0 K-hGH I N C H I L D R E N
M Ishikawa 1, Y Hasegawa 2, Y Hashimoto 3 Tachibana 4, T Tanaka ~, E Tokuhiro s, T Yasuda ~, S Yokoya75 National Children's Med Res Ctr; 2 Kiyose Children's Hospital; 3Mitsui Pharmaceuticals, Inc.; 4 Kanagawa Children's Med Ctr; 5Odawara City Hospital; ~Chiba University; rToranomon Hospital. Twenty K-human GH (20 K) differs from the 22 K-human GH (22 K) by deletion of 15 amino acids, residues 32-46. Since serum 20 K has not been measured directly, the percentage of 20 K in human GH (hGH) has not been determined. We measured the serum 20 K and 22 K in normal children, patients with growth hormone deficiency (GHD), non-GHD short stature (nGHD), Turner syndrome, and precocious puberty. The 20 K and 22 K were measured by ELISA using anti-hGH monoclonal antibodies specific for 20 K or 22 K. The percentage of 20 K in hGH was calculated as the percentage of 20 K in the total of 20 K and 22 K. In normal boys and girls, mean serum 20 K was respectively 152 and 123 pg/ml, and mean serum 22 K was 2.4 and 2.1 ng/ml. The mean percentage of 20 K were 5.9 and 6.0%, respectively. There was no significant difference in the percentage of 20 K between boys and girls, between prepuberty and puberty. And also there was no significant difference in the percentage of 20 K between normal children and the patients
O-27 C O M P A R I S O N B E T W E E N IGF-I A N D GH IN PERINATAL G R O W T H
Z Laron, B Klinger, Schneider Children's Med. Ctr. Israel, Sackler Fac. Med., Tel Aviv Univ., Israel. We have investigated the growth pattern during the first 5 years of life in four patients (pts) (2 M, 2 F) with cong. Isolated growth hormone deficiency (IGHD = secondary IGF-I deficiency) and five pts (3 M, 2 F) with GH resistance (Laron Syndrome=LS=primary IGF-I deficiency). One pt was GHBP > and 4 GHBP Birth length ranged from 45-49 cm in both groups (from -2.5 to -4.5 SDS). Untreated LS pts progressively slowed their growth decreasing the height (ht) SDS from -3.5 to -6.5. IGF-I treatment (200 mg/kg/day s.c.) to three LS pts accelerated growth with a gain of 0.5 to 1.5 ht SDS in 2 years. During IGF-I treatment basal s.c. IGF-I rose from 3-6 to 7-20 nM/1 denoting optimal dosage. There was also a rise in serum procollagens. Untreated IGHD pts decreased ht SDS from -2.5 to 5.2 at 1 year and -5.7 at 2 years. Initiation of hGH treatment (0.07 U/kg/day) between ages 1-4 accelerated growth velocity with gain of 1.2 to 2.4 ht SDS in 3 years. All untreated babies had borderline or below normal head circumferences. Treatment by IGF-I or hGH induced a rapid catch-up of the head size, crossing normal limits within a half to 2 years. In the two untreated LS pts, head circumference remained below normal. Despite a similar birth length, infants with IGHD responded in their linear growth better to hGH than did infants with LS to IGF-I. The response of the brain growth was similar in both groups. Our observations suggest differential effects of hGH and IGF-I on growth. It seems that for optimal linear growth, IGF-I requires hGH either in a preparatory phase or for synergistic action. This is not the case for brain and other organ growth. Partial resistance to IGF-I cannot be excluded. 0 - 2 8 L O N G I T U D I N A L CHANGES I N G R O W T H H O R M O N E RELEASE, BODY COMPOSITION, A N D BODY FAT D I S T R I B U T I O N A R E INVERSELY RELATED IN C H I L D R E N A N D ADOLESCENTS
JN Roemmich ~, PA Clark ~, SS Berr z, VM Mai 2, A Weltman 3,4, AD Rogol ~,5, Departments of ~Pediatrics, 2Radiology, 3Education, 4Medicine, 5pharmacology, University of Virginia. We examined the relationships among 12-month changes in sex steroid levels and criterion measures of body composition [body density (underwater weighing) corrected for body water (deuterium dilution) and mineral (DEXA)], abdominal fat distribution [MRI for visceral fat (AVF) and subcutaneous fat (ASF)], subcutaneous fat distribution (sMnfolds) and GH release (ql0 min from 1800 h to 0600 h) in prepubertal and pubertal boys (n=l 1; n=9) and girls (n=9; n=12). At baseline, neither the area under the GH-time curve (AUC), the sum of the GH peak heights (sum GH pk hts), or the mean nadir GH level (GH nadir) were related to the adiposity variables. The 12-month change in AUC was inversely related to the change in sum of sMnfolds (r= -0.31, P = 0.05), fat mass (FM) (r= -0.45, P = 0.003), and ASF (r= -0.41, P = 0.02) but not the AVF (r= 0.11, P = 0.53) and directly related to the change in free-testosterone (r= 0.38, P = 0.03). The change in sum GH pk hts was inversely related to the change in the sum of limb sMnfolds (peripheral subcutaneous fat; r = -0.34, P = 0.03). The change in GH nadir was not significantly related to any adiposity or sex steroid variables. In stepwise regression, the change in FM and free-testosterone accounted for 28% of the variance for the change in AUC. We conclude that due to large inter-individual differences in GH release, cross-sectional studies may not adequately describe the relationship between adiposity and GH release in children and the various GH pulse attributes are influenced by different adiposity/fat distribution factors. [Funded by NIH HD 32631, GCRC RR00847, and the Genentech Foundation for Growth and Development.]