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September 1, 1982Endocrinology

Effect of Prolonged Low Dose Infusion of Angiotensin II and Aldosterone on Rat Smooth Muscle and Adrenal Angiotensin II Receptors*

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Why the study?

Does prolonged low dose infusion of Angiotensin II or aldosterone alter Angiotensin II receptor kinetics in rat smooth muscle and adrenal tissues?

Population

Rats (uterine myometrium and adrenal glomerulosa tissues)

Comparison

Low dose infusion of Angiotensin II for 7 days… vs Control (no infusion)

Design

Preclinical

Follow-up

7 days

Authors

JDJanice G. DouglasSt. Michael's HospitalGBG. P. BrownUniversity at Buffalo, State University of New York

Discussion

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Implication

Animal findings on receptor kinetics should not guide human therapy; leaves open mechanisms beyond ligand levels in cardiovascular models.

Key Points

  • To determine how sustained alterations in circulating angiotensin II and aldosterone concentrations influence the affinity and density of angiotensin II receptors in smooth muscle and adrenal tissues.
  • Infused rats continuously with low-dose angiotensin II for 7 days or with aldosterone via osmotic minipumps to raise plasma aldosterone 10-fold, with a subset receiving supplemental potassium chloride in drinking water.
  • Measured receptor affinity (dissociation constant, Kd) and concentration in uterine myometrium and adrenal glomerulosa using a radioreceptor binding assay.
  • Angiotensin II infusion significantly suppressed plasma renin activity, reduced uterine myometrium Kd to 29% of control values, increased adrenal glomerulosa Kd by 115%, and increased adrenal receptor numbers without changing uterine receptor density.
  • Aldosterone infusion increased myometrial receptor numbers 2.7-fold, reduced adrenal receptors by 42% to 58% (an effect attenuated by potassium chloride supplementation), and decreased adrenal Kd by 22%.

Structured PICO

Does prolonged low dose infusion of Angiotensin II or aldosterone alter Angiotensin II receptor kinetics in rat smooth muscle and adrenal tissues?

P
Population
Rats (uterine myometrium and adrenal glomerulosa tissues)
I
Intervention
Low dose infusion of Angiotensin II for 7 days, or continuous infusion of aldosterone with osmotic minipumps (with or without supplemental KCl)
C
Comparator
Control (no infusion)
O
Outcome
Angiotensin II receptor kinetics (Kd and number of receptors) in uterine myometrium and adrenal glomerulosasurrogate

Prolonged infusion of Angiotensin II or aldosterone alters Angiotensin II receptor affinity and concentration in rat tissues, suggesting factors beyond endogenous Ang II concentration influence receptor kinetics.

Cite This Study

Douglas et al. (1982) studied this question.

synapsesocial.com/papers/6a8384ff6524aee222604f17https://doi.org/10.1210/endo-111-3-988
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Also Consider

Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context:

  1. 1Plasma Angiotensin II Concentration Regulates Vascular but Not Adrenal Responsiveness to Restriction of Sodium Intake in Normal Man1981 · 34 citations
  2. 2ANGIOTONIN-ACTIVATOR, RENIN- AND ANGIOTONIN-INHIBITOR, AND THE MECHANISM OF ANGIOTONIN TACHYPHYLAXIS IN NORMAL, HYPERTENSIVE, AND NEPHRECTOMIZED ANIMALS1940 · 109 citations
  3. 3Arterial Hypertension Elicited by Subpressor Amounts of Angiotensin1965 · 140 citations
  4. 4Reciprocal Influence of Salt Intake on Adrenal Glomerulosa and Renal Vascular Responses to Angiotensin II in Normal Man1974 · 333 citations
  5. 5Potassium ion as a regulator of adrenal angiotensin II receptors1980 · 15 citations