Increase in specific binding of insulin-like growth factor (IGF) II to type 1 IGF receptors on erythrocytes of hypopituitary children receiving growth hormone therapy.
Specific receptor binding for insulin-like growth factors (IGFs) is measurable in young erythrocytes. Cells of similar age, Fraction A, can be reproducibly obtained by dextran gradient centrifugation from 5-10 ml of blood. We now report IGF-II specific binding to Fraction A erythrocytes from normal children and children with growth hormone deficiency. Normal controls (Group 1) were 5 male volunteers (14.7 +/- .6 years, mean +/- SEM) and 10 children with constitutional short stature (11.4 +/- 1.6 years) who had normal 6-hour daytime growth hormone profiles and plasma IGF-I values. Twelve growth hormone deficient children (Group 2), aged 13.7 +/- 1.1 years, had samples taken after 2 months without growth hormone therapy and again following 2 months with growth hormone (0.1 U/kg 3 times per week) therapy. The percent of total erythrocytes in Fraction A did not differ in the two groups of children. Group 1 had IGF-II specific binding of 10.2 +/- 0.6% (per 3 X 10(9) cells). IGF-II specific binding was less in Group 2 at 6.6 +/- 0.8% (p less than 0.002). With growth hormone therapy, IGF-II specific binding increased to 10.4 +/- 1.0% (p less than 0.02), a value not different from that seen in Group 1. Corresponding plasma IGF-II and IGF-I values showed a positive correlation with IGF-II specific binding (r = 0.54 and r = 0.56 respectively, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Costigan
C D
CD
Department of Pediatrics, McGill University, Montreal Children's Hospital Research Institute, Quebec.
Polychronakos
C
C
Guyda
H J
HJ
Posner
B I
BI
D000293:Adolescent; D002648:Child; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D013006:Growth Hormone / Q000627:therapeutic use*; D006801:Humans; D007018:Hypopituitarism / Q000097:blood* / Q000188:drug therapy; D007334:Insulin-Like Growth Factor I / Q000097:blood; D007335:Insulin-Like Growth Factor II / Q000097:blood*; D008297:Male; D011972:Receptor, Insulin / Q000378:metabolism*; D017451:Receptors, Somatomedin; D013002:Somatomedins / Q000097:blood*
D017451:Receptors, Somatomedin; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013006:Growth Hormone; D011972:Receptor, Insulin