Cardiac output and renal function during insulin hypertension in Sprague-Dawley rats

Michael W Brands, William F. Lee, Henry L. Keen, Magdalena Alonso-Galicia, Dion H. Zappe, John E. Hall

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Abstract

Hyperinsulinemia has been reported to cause hypertension in rats; however, the renal and hemodynamic mechanisms are not known. In this study, changes in renal function, cardiac output (CO), and total peripheral resistance (TPR) were measured during chronic insulin infusion in eight rats (~350 g). After a 4-day control period, a 7-day insulin infusion was begun (1.5 mU · kg-1 · min-1 iv), together with glucose (22 mg · kg-1 · min-1 iv) to prevent hypoglycemia. Mean arterial pressure (MAP), CO, TPR, and heart rate were measured 24 h/day. MAP increased from 92 ± 1 to 100 ± 2 mmHg on day 1 and was 108 ± 4 mmHg by day 7 of insulin. CO tended to decrease during insulin infusion, although not significantly, averaging 94 ± 4% of the control value of 121 ± 7 ml/min. Heart rate did not change significantly from the control value of 384 ± 8 beats/min. TPR increased significantly to 122 ± 11% of control by day 7. In five rats, glomerular filtration rate and effective renal plasma flow decreased to 73 ± 4 and 66 ± 5% of control, respectively, during insulin. Urinary sodium excretion averaged 2.6 ± 0.1 and 2.7 ± 0.1 meq/day during the control and insulin- infusion periods, respectively. These results indicate that insulin hypertension in rats is initiated by an increase in TPR rather than by increased CO. Also, the fact that sodium balance was maintained at elevated arterial pressure suggests that the ability of the kidneys to excrete sodium was impaired chronically during insulin infusion.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume271
Issue number1 40-1
StatePublished - Jul 1 1996
Externally publishedYes

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Cardiac Output
Sprague Dawley Rats
Insulin
Hypertension
Kidney
Vascular Resistance
Arterial Pressure
Sodium
Heart Rate
Effective Renal Plasma Flow
Hyperinsulinism
Glomerular Filtration Rate
Hypoglycemia
Hemodynamics
Glucose

Keywords

  • glomerular filtration rate
  • peripheral vascular resistance
  • sodium excretion

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Cardiac output and renal function during insulin hypertension in Sprague-Dawley rats. / Brands, Michael W; Lee, William F.; Keen, Henry L.; Alonso-Galicia, Magdalena; Zappe, Dion H.; Hall, John E.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 271, No. 1 40-1, 01.07.1996.

Research output: Contribution to journalArticle

Brands, Michael W ; Lee, William F. ; Keen, Henry L. ; Alonso-Galicia, Magdalena ; Zappe, Dion H. ; Hall, John E. / Cardiac output and renal function during insulin hypertension in Sprague-Dawley rats. In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology. 1996 ; Vol. 271, No. 1 40-1.
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