Insulin action and secretion in hypertension in the absence of metabolic syndrome: model-based assessment from oral glucose tolerance test

Roberto Burattini, Francesco Di Nardo, Fabrizio Casagrande, Massimo Boemi, Pierpaolo Morosini

Research output: Contribution to journalArticlepeer-review

Abstract

Relationship between insulin action and secretion was analyzed in 10 hypertensive patients (H group; 5 male, 5 female; 56.9 ± 2.5 years) compared with 10 normotensive subjects (N group; 5 male, 5 female; 51.7 ± 3.7 years; P > .05) matched for age, sex, and body mass index. All participants (normoglycemic, nonobese, and not affected by metabolic syndrome) underwent a 5-hour, 22-sample, oral (75 g) glucose tolerance test. Insulin sensitivity was quantified by quantitative insulin sensitivity check index and an insulin sensitivity index computed by minimal-model-based "integral equation." β-Cell responsivity indexes (dynamic, Φd; static, Φs; and global, Φoral) were estimated by C-peptide oral minimal model. Compared with the N group, our H group featured no significant difference (P > .05) in fasting glycemia, significant (P <.02) increase in plasma insulin (93%) and C-peptide (53%) concentrations, and significant (P <.01) reduction in both quantitative insulin sensitivity check index (10%) and insulin sensitivity index (68%). No significant variations of mean Φd, Φs, and Φoralwere observed across the 2 groups in response to glucose challenge. Thus, insulin sensitivity deterioration in hypertension was not mirrored by a reciprocal change in β-cell responsivity. Nevertheless, our H group featured a 143% (P <.005) increase in the area under the curve of circulating insulin and a 34% (P <.01) reduction in the ratio between the area under C-peptide curve and the area under the curve of circulating insulin. These results support the hypothesis that decreased insulin clearance in hypertensive patients, not affected by metabolic syndrome, is a further regulatory mechanism, in addition to increased insulin secretion, to compensate for insulin resistance.

Original languageEnglish
Pages (from-to)80-92
Number of pages13
JournalMetabolism
Volume58
Issue number1
DOIs
Publication statusPublished - 2009

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

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