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WENDELL E. NICHOLSON, JON H. LEVINE, DAVID N. ORTH, Hormonal Regulation of Renal Ornithine Decarboxylase Activity in the Rat, Endocrinology, Volume 98, Issue 1, 1 January 1976, Pages 123–128, https://doi.org/10.1210/endo-98-1-123
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The regulation of the activity of the renal enzyme omithine decarboxylase (L-ornithine carboxy-lyase, EC 4.1.1.17) was examined in the rat. In the intact animal adapted to a light/dark cycle of 14 hours and 10 hours, respectively, the level of renal omithine decarboxylase activity was rhythmical and paralleled the diurnal rhythm in plasma corticosteroid concentration. Renal omithine decarboxylase activity and plasma corticosterone were highest during the early hours of darkness and lowest during the hours of light. Following hypophysectomy, the level of renal omithine decarboxylase activity declined rapidly and remained low and without a demonstrable diurnal rhythm. When pituitary hormone levels were temporarily restored in the hypophysectomized rat by the injection of pituitary extract, renal ornithine decarboxylase activity increased rapidly, reached a peak within 8 hours, and returned toward pre-injection levels by 12 hours. Exogenous growth hormone, ACTH and cortisol each increased renal omithine decarboxylase activity in the hypophysectomized rat, with the highest levels of activity being achieved with growth hormone. Other pituitary hormones (FSH, LH, TSH and prolactin) were ineffective. After bilateral adrenalectomy, renal omithine decarboxylase activity retained a rhythmical pattern similar to that observed in the intact rat, but the levels were increased. Growth hormone and cortisol increased renal ornithine decarboxylase activity in the adrenalectomized-hypophysectomized animal to the same extent as in the hypophysectomized animal, but ACTH was almost totally ineffective. These data suggest that the pituitary plays a major role in theregulation of renal ornithine decarboxylase activity in the rat, primarily through the rhythmical secretion of growth hormone and ACTH.(Endocrinology98: 123,1976)
