Evidence that selenium induces growth retardation through reduced growth hormone and somatomedin C production

Growth retardation has long been known to be a major characteristic in selenium-intoxicated animals. As selenium is known to accumulate in the anterior pituitary, especially in the secretory granules of the somatotroph, we have investigated the GH secretion after GH-releasing factor 40 stimulation and the somatomedin C secretion in young male rats exposed to 15 mg sodium selenite/liter drinking water. The immediate output to 900 +/- 120 ng/ml GH in control animals was reduced to 200 +/- 69.4 ng/ml in selenium-treated animals. The somatomedin C level was reduced from 720 +/- 16 ng/ml in control to 119 +/- 17 ng/ml in selenium-treated animals. Both differences were highly significant. These findings suggest that growth retardation in selenium-treated rats could be mediated by reduced GH and somatomedin C production.