Somatomedins and steroids.
Somatomedin levels measured by radioreceptor assay, competitive protein-binding assay or radioimmunoassay are normal in hypercortisolism; the decrease of somatomedin activity consistently found in this condition is due to an increase in circulating somatomedin inhibitors resulting in an inhibition of somatomedin action. Progestagens could possibly have a direct stimulatory effect on somatomedin-C (Sm-C) production. During puberty, the increase of Sm-C is correlated with the increase in plasma estradiol and testosterone. In young subjects, relatively low doses of estrogens and of testosterone enhance Sm-C secretion, and in adult menstruating women, a positive relationship is found between testosterone and Sm-C values. An inhibitory effect of estrogens on Sm-C is observed with higher doses and/or in older subjects. Thus, somatomedin levels might be modulated by variations of sex steroids.
D004967:Estrogens / Q000378:metabolism; D005260:Female; D005938:Glucocorticoids / Q000378:metabolism; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D011372:Progestins / Q000378:metabolism; D013002:Somatomedins / Q000378:metabolism*; D013256:Steroids / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism
D004967:Estrogens; D005938:Glucocorticoids; D011372:Progestins; D013002:Somatomedins; D013256:Steroids; D013739:Testosterone; D007334:Insulin-Like Growth Factor I