Serum growth hormone binding protein activity in healthy neonates, children and young adults: correlation with age, height and weight.
Serum growth hormone binding protein (GHBP) activity was estimated in healthy neonates (n = 6), children and adolescents (n = 97) and young adults (n = 19). GHBP activity was measured by incubating 125I-hGH (human growth hormone) (approximately 25,000 c.p.m.) with serum (100 microliters) in the presence and in the absence of excess unlabelled hGH, followed by separation of specifically bound 125I-hGHBP complexes from free 125I-hGH by gel filtration on Ultrogel AcA44 minicolumns. The results are expressed as the percentage specific binding relative to an adult reference serum (%RSB), after correction for endogenous hGH of the unknown serum. The between-assay coefficients of variation for two sera of %RSB activity of 51.2 and 115.4% were 6.0 and 7.0% respectively. In neonates, low values of serum GHBP were found (%RSB = 27.1 +/- 5.0 SEM) followed by a major rise during the first 6 years of life to a mean value (%RSB = 68.3 +/- 4.1 SEM) which more than doubled that of neonates. Thereafter, values rose progressively throughout childhood and puberty to reach maximum values in young adults (%RSB = 95.0 +/- 3.1 SEM). A novel observation was that serum GHBP activity correlated significantly with height standard deviation score (SDS) (males: r = 0.77, P less than 0.001; females: r = 0.56, P = 0.01) and weight SDS (P less than 0.001) for both sexes before puberty. During puberty GHBP correlated only with weight SDS in males (r = 0.60, P less than 0.01). In all age groups studied, no correlation could be found between serum GHBP and height velocity.
Silbergeld
A
A
Institute of Pediatric and Adolescent Endocrinology, Tel Aviv University, Israel.
Lazar
L
L
Erster
B
B
Keret
R
R
Tepper
R
R
Laron
Z
Z
D000293:Adolescent; D000328:Adult; D000375:Aging; D000704:Analysis of Variance; D002352:Carrier Proteins / Q000097:blood*; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011627:Puberty / Q000502:physiology; D012737:Sex Factors
D002352:Carrier Proteins; C051815:somatotropin-binding protein