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RESEARCH PRODUCT

Aldosterone biosynthesis induced by ACTH and angiotensin II in newborn rat adrenocortical cells transfected by c-EJ-Ha-ras oncogene

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Abstract Adrenocortical cells were obtained by fractionated trypsination of newborn rat adrenal glands and transfected with a plasmid containing the EJ T24 -Ha-ras oncogene. Isolation of adhesive cells led to a proliferative cell line with an overexpression of 21 kDa ras protein. These cells incubated with corticosterone or deoxycorticosterone as the precursor produced a high level of 18-hydroxycorticosterone and aldosterone as identified by gas chromatography- mass spectrometry. ACTH and angiotensin II increased the basal production of aldosterone nineteen-fold and six-fold respectively. Under ACTH stimulation the ratio between aldosterone and 18-hydroxycorticosterone production was 1:3. The transformation of corticosterone under angiotensin II stimulation yielded up to 41% of 18-hydroxycorticosterone (4.7 μg/mg of cell protein per 24h) and 4.4% of aldosterone (0.5 μg/mg of cell protein per 24h) in a low potassium concentration medium (6 mmol/l). To our knowledge this is the first report of continuous proliferative adrenocortical cells producing aldosterone.