Opposite feedback control of renin and aldosterone biosynthesis in the adrenal cortex by angiotensin II AT1-subtype receptors

Hypertension. 1997 Sep;30(3 Pt 2):563-8. doi: 10.1161/01.hyp.30.3.563.

Abstract

The aims of this study were to identify whether tissue renin is regulated by a negative-feedback mechanism produced by locally generated angiotensin (Ang II) in the adrenal cortex and to detect the pathway of Ang II modulation. For this purpose, in 36 12-week old, salt-restricted, nephrectomized Sprague-Dawley rats, we studied the effects of the Ang II AT1-subtype receptor antagonist losartan and of the Ang II AT2-subtype receptor antagonist PD123319 on renin mRNA and activity, aldosterone synthase mRNA, and AT1a-, AT1b-, and AT2-subtype receptor expression in the adrenal cortex. Ten additional rats, kept on a regular diet and then nephrectomized, were also studied. In salt-restricted, nephrectomized rats, losartan administration caused increases of adrenal renin mRNA (P<.05) and activity (P<.05) and a concomitant reduction of aldosterone synthase mRNA (P<.05). In addition, after losartan AT1b, receptor mRNA was reduced (P<.05), AT1a receptor mRNA was unchanged, and AT2 mRNA was increased (P<.05). PD123319 did not significantly modify any of these parameters. In conclusion, in salt-restricted, nephrectomized rats, selective antagonism of AT1-subtype receptors stimulates the expression and the activity of renin in the adrenal cortex. This observation demonstrates that Ang II locally formed in the adrenal cortex exerts a modulatory negative-feedback action on adrenal renin biosynthesis independent of the influence of the circulating renin-Ang system; this action is largely mediated through the AT1b-subtype receptors.

MeSH terms

  • Adrenal Cortex / metabolism*
  • Aldosterone / biosynthesis*
  • Animals
  • Biphenyl Compounds / pharmacology
  • Feedback
  • Imidazoles / pharmacology
  • Losartan
  • Male
  • Pyridines / pharmacology
  • RNA, Messenger / analysis
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Angiotensin / classification
  • Receptors, Angiotensin / genetics
  • Receptors, Angiotensin / physiology*
  • Renin / biosynthesis*
  • Tetrazoles / pharmacology

Substances

  • Biphenyl Compounds
  • Imidazoles
  • Pyridines
  • RNA, Messenger
  • Receptors, Angiotensin
  • Tetrazoles
  • PD 123319
  • Aldosterone
  • Renin
  • Losartan