Circulating catecholamines and metabolic effects of captopril in NIDDM patients

  1. Anna Santucci, MD
  1. Institute of I Clinica Medica and the Andrea Cesalpino Foundation, University of Rome La Sapienza Rome, Italy
  2. Department of Internal Medicine and Public Health, University of L'Aquila Rome, Italy
  1. Address correspondence and reprint requests to Giancarlo De Mattia, MD, Università La Sapienza, Istituto di I Clinica Medica, 00161 Rome, Italy

Abstract

OBJECTIVE To evaluate the effects of captopril on circulating catecholamine levels in NIDDM patients and the possible relationship between captopril-related changes in circulating catecholamine levels and insulin sensitivity.

RESEARCH DESIGN AND METHODS Fourteen nonobese normotensive NIDDM men (aged 44.5 ± 5.1 years) underwent a 2-h euglycemic-hyperinsulinemic clamp (40 mU·m−2 · min−1). Baseline evaluation of insulin sensitivity was followed by the random assignment of each patient to either captopril or placebo treatment, according to a crossover double-blind design. Euglycemic-hyperinsulinemic clamp studies were then repeated for all patients after both placebo and captopril treatments. Plasma norepinephrine (NE) and epinephrine (E) levels were assessed before, during, and after each clamp.

RESULTS Resulting data showed that plasma catecholamine levels increased during baseline euglycemic-hyperinsulinemic clamp (NE: +23.6% time 0 vs. time 120 min, P < 0.05; E: +24.8% time 0 vs. time 120 min, P < 0.05). Captopril treatment significantly increased total glucose uptake (from 19.0 ± 9.0 to 26.8 ± 10.1 mmol·kg−1 · min−1, P < 0.05) and reduced baseline plasma NE (P < 0.001) and E (P < 0.05) levels. However, the magnitude of the NE (+25.7% time 0 vs. time 120 min, P < 0.001) and E (+27.2% time 0 vs. time 120 min, P < 0.05) increments during euglycemic hyperinsulinemia were not affected by the drug. Percentage changes in the ratio of total body glucose uptake to circulating insulin levels and corresponding decrements of baseline plasma E levels after captopril therapy were negatively correlated (r = −0.57, P < 0.05).

CONCLUSIONS The reduction of circulating catecholamines could contribute, at least in part, to the captopril-related amelioration of insulin sensitivity.

  • Received June 19, 1995.
  • Revision received October 12, 1995.
  • Accepted October 12, 1995.
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