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EFFECT OF ANDROGENS ON PLASMA SOMATOMEDIN‐C/INSULIN‐LIKE GROWTH FACTOR I RESPONSES TO GROWTH HORMONE
Author(s) -
CRAFT W. H.,
UNDERWOOD L. E.
Publication year - 1984
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1984.tb00103.x
Subject(s) - endocrinology , medicine , testosterone (patch) , somatomedin , androgen , hormone , growth hormone , chemistry , biology
SUMMARY In search of the mechanism for the relatively high plasma somatomedin‐C (Sm‐C) concentrations in pubertal boys and girls, we have measured the plasma Sm‐C responses to exogenous growth hormone (GH) in prepubertal hypopituitary boys before and after testosterone administration. Sm‐C responses were determined in 5 hypopituitary boys (9–14 years of age) who were given two successive injections of GH (0·1 U/kg) 48 h apart. Eight days later, after administering 200 mg testosterone IM, their Sm‐C responses to the same GH challenge were reassessed. There were no significant differences between the pre‐testosterone Sm‐C response to GH and the post‐testosterone response, despite evidence for reductions in 24 h urinary nitrogen excretion and serum urea nitrogen concentrations in response to testosterone. The results provide no evidence that androgen augments the effect of GH to raise plasma Sm‐C during puberty, or that androgen has a direct stimulatory effect on Sm‐C production. By inference and from published reports, it appears more likely that a sex hormone‐stimulated increase in GH secretion is responsible for the increased Sm‐C observed during puberty.