title: The effect of sex steroids on radioimmunoassayable plasma somatomedin C concentrations.
abstract: While the effect of sex steroids on growth is well known, their effects on somatomedin C, a mediator of growth, are unclear. To investigate the effect of sex steroids on somatomedin C (Sm-C) concentrations, Sm-C was measured in adults receiving pharmacological doses of various sex steroids (estrogens, testosterone, and medroxyprogesterone acetate). Testosterone therapy had no effect on the somatomedin C concentration. Although both estrogen and medroxyprogesterone acetate therapy reduced the plasma testosterone concentration into the normal female range, they had different effects on Sm-C concentrations. Estrogen therapy produced no detectable change in the Sm-C concentration; medroxyprogesterone acetate caused an increase in the plasma somatomedin C concentration (P less than 0.001). Since medroxyprogesterone acetate also does not increase the serum GH concentration, other mechanisms by which medroxyprogesterone acetate stimulates Sm-C production are discussed.
mesh_terms: D000328:Adult; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D012739:Gonadal Steroid Hormones / Q000494:pharmacology*; D006801:Humans; D007334:Insulin-Like Growth Factor I; D008297:Male; D008525:Medroxyprogesterone / Q000031:analogs & derivatives / Q000494:pharmacology; D017258:Medroxyprogesterone Acetate; D008875:Middle Aged; D011863:Radioimmunoassay; D012742:Sex Offenses; D013002:Somatomedins / Q000097:blood*; D013739:Testosterone / Q000097:blood / Q000494:pharmacology; D014189:Transsexualism / Q000097:blood
chemical_list: D004967:Estrogens; D012739:Gonadal Steroid Hormones; D013002:Somatomedins; D013739:Testosterone; D007334:Insulin-Like Growth Factor I; D017258:Medroxyprogesterone Acetate; D008525:Medroxyprogesterone