Cytochromes P-45011 beta, P-450scc and adrenodoxin gene expression during adrenocortical regeneration in the rat.

Circulating levels of 11-deoxycorticosterone are increased during the development of adrenal-regeneration hypertension. The present studies were undertaken to examine the mechanisms involved in this increase. Plasmids containing cDNA inserts coding for cytochrome P-45011 beta, cytochrome P-450scc and adrenodoxin were used to determine, by Northern blot analysis, mRNA levels at 1, 2 and 3 weeks of adrenal regeneration. There was a striking decrease in mRNA transcripts for all three enzymes during the first week of regeneration when compared with intact adrenal tissue. Over the next 2 weeks the mRNA levels increased to 64% for P-45011 beta, to 80% for P-450scc and to 82% for adrenodoxin. Actin mRNA levels were 70% of control levels in the first week but were back to control levels by the second week. The present findings suggest that decreased expression of steroid 11 beta-hydroxylase could contribute to the increased secretion of 11-deoxycorticosterone during the early stages of adrenal regeneration.