Endocrine Modification of the Developmental Formation of Ornithine Aminotransferase in Rat Tissues

In rat kidney, treatment with estrogen but not glucocorticoids elevates ornithine aminotransferase prematurely, and the effect of estrogen is prevented by simultaneously administered triamcinolone.

Abstract

Abstract Ornithine aminotransferase concentrations are under the control of a sequence of antagonistic hormonal factors differing with age and different in liver and kidney. Developmental formation of ornithine aminotransferase normally occurs in rat liver 2 weeks after birth. A single injection of glucocorticoid as early as 4 days after birth prematurely raises the rate of formation to adult levels in 16 to 24 hours, whereas either estrogen administration or adrenalectomy inhibits the normal accumulation of the enzyme in the third postnatal week. Estrogen given 6 hours before glucocorticoids also prevents the rise in younger rats. The level in adult animals is not changed by glucocorticoids or adrenalectomy. In rat kidney, treatment with estrogen but not glucocorticoids elevates ornithine aminotransferase prematurely. The effect of estrogen is prevented by simultaneously administered triamcinolone.