A DEXAMETHASONE SENSITIVE STEP IN THE CELL CYCLE OF ADRENOCORTICAL CELLS

in Journal of Endocrinology
Author:
N. A. WRIGHT
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Corticotrophin (ACTH) has been shown to increase adrenocortical DNA content (Bransome, 1968) and to stimulate adrenal DNA polymerase and thymidine kinase activity (Masui & Garren, 1970). Bransome (1968) has shown that dexamethasone also produces a significant decrease in adrenocortical DNA. It is therefore surprising that a recent report by Ueberberg, Stöcker & Städtler (1970) concluded that cell proliferation is not influenced by dexamethasone treatment. The present results indicate that in prepubertal rats dexamethasone has a profound inhibitory effect or adrenocortical cell proliferation by acting on a particular point in the cell cycle.

Male Wistar rats aged 14 days were given a single i.p. injection of 3 μg dexamethasone phosphate (Merck, Sharp and Dohme)/g body weight. Controls received normal saline. Animals were killed serially thereafter. Tritiated thymidine ([3H]Tdr) was administered 1 h before death, and autoradiographs of the adrenal glands prepared as previously described (Wright, 1971). The adrenal cortex was

 

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