Growth hormone, somatomedin levels and growth regulation in Turner's syndrome.
In a total of 56 children and adolescents with Turner's syndrome (41 with karyotype 45,X) basal serum levels of somatomedin bioactivity, Sm-C/IGF-I (RIA), IGF II (RIA), GH response to arginine and GHRH (GRF(1-29)NH2), and spontaneous GH secretion during 5.5 h of deep sleep were determined in a cross-sectional manner. GH responses to GRF and arginine as well as IGF-II levels were found to be in the normal range. Levels of somatomedin bioactivity were higher than normal before a bone age of 10 years, in the low-normal range thereafter, and below normal in some patients. Levels of Sm-C/IGF-I were found normal before and low-normal after a bone age of ten years. There was a trend towards increasing Sm-C/IGF-I levels with age. In contrast to the normal pattern, spontaneous sleep-related GH secretion was declining with age and did not show the puberty-associated rise. These findings suggest a normally functioning growth hormone-somatomedin axis in Turner's syndrome with alterations of its functioning level occurring secondarily as a result of absent gonadal activation. In single patients abnormally low growth hormone and/or somatomedin secretion may be present.
University Children's Hospital, FRG.
M B
MB
Ranke
W F
WF
Blum
F
F
Haug
W
W
Rosendahl
A
A
Attanasio
H
H
Enders
D
D
Gupta
J R
JR
Bierich
D000293:Adolescent; D000365:Age Determination by Skeleton; D002648:Child; D006128:Growth; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000097:blood; D007335:Insulin-Like Growth Factor II / Q000097:blood; D013002:Somatomedins / Q000097:blood*; D014424:Turner Syndrome / Q000097:blood* / Q000503:physiopathology
D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013006:Growth Hormone