Cited by 252Blood Pressure and Hypertension StudiesDiabetes, Cardiovascular Risks, and LipoproteinsNitric Oxide and Endothelin Effects

The DOI matches its Crossref record; 50 of the 50 references it cites were found in a registry or an index; none of the 35 sources its claims cite is checked for support yet.

Abnormal sympathetic overactivity evoked by insulin in the skeletal muscle of patients with essential hypertension.

Open access
Lembo, G, Napoli, R, Capaldo, B, Rendina, V, Iaccarino, G, Volpe, M, Trimarco, B, Saccà, L·1992·Journal of Clinical Investigation

Abstract

The reason why hyperinsulinemia is associated with essential hypertension is not known. To test the hypothesis of a pathophysiologic link mediated by the sympathetic nervous system, we measured the changes in forearm norepinephrine release, by using the forearm perfusion technique in conjunction with the infusion of tritiated NE, in patients with essential hypertension and in normal subjects receiving insulin intravenously (1 mU/kg per min) while maintaining euglycemia. Hyperinsulinemia (50-60 microU/ml in the deep forearm vein) evoked a significant increase in forearm NE release in both groups of subjects. However, the response of hypertensives was threefold greater compared to that of normotensives (2.28 +/- 45 ng.liter-1.min-1 in hypertensives and 0.80 +/- 0.27 ng.liter-1 in normals; P less than 0.01). Forearm glucose uptake rose to 5.1 +/- .7 mg.liter-1.min-1 in response to insulin in hypertensives and to 7.9 +/- 1.3 mg.liter-1.min-1 in normotensives (P less than 0.05). To clarify whether insulin action was due to a direct effect on muscle NE metabolism, in another set of experiments insulin was infused locally into the brachial artery to expose only the forearm tissues to the same insulin levels as in the systemic studies. During local hyperinsulinemia, forearm NE release remained virtually unchanged both in hypertensive and in normal subjects. Furthermore, forearm glucose disposal was activated to a similar extent in both groups (5.0 +/- 0.6 and 5.2 +/- 1.1 mg.liter-1.min-1 in hypertensives and in normals, respectively). These data demonstrate that: (a) insulin evokes an abnormal muscle sympathetic overactivity in essential hypertension which is mediated by mechanisms involving the central nervous system; and (b) insulin resistance associated with hypertension is demonstrable in the skeletal muscle tissue only with systemic insulin administration which produces muscle sympathetic overactivity. The data fit the hypothesis that the sympathetic system mediates the pathophysiologic link between hyperinsulinemia and essential hypertension.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

In patients with essential hypertension, systemic euglycemic hyperinsulinemia evoked a threefold greater increase in forearm skeletal muscle norepinephrine release than in normotensive controls. Local intra-arterial insulin did not change norepinephrine release in either group, suggesting the abnormal sympathetic response is centrally mediated rather than a direct muscle effect.

Key findings

  • Systemic insulin infusion increased forearm NE release in both groups, but the absolute rise was threefold higher in hypertensives (2.28±0.45 vs. 0.80±0.27 ng·liter⁻¹·min⁻¹; P < 0.01); percent increases were 140% in hypertensives (P < 0.001) and 35% in normotensives (P < 0.05).
  • During systemic insulin, forearm glucose uptake was lower in hypertensives than normotensives (5.1±0.7 vs. 7.9±1.3 mg·liter⁻¹·min⁻¹; P < 0.05), and whole-body glucose utilization was also lower (4.6±0.3 vs. 5.8±0.5 mg/kg per min; P < 0.05).
  • During local intrabrachial insulin, forearm NE release remained virtually unchanged in both groups, while forearm glucose disposal was similar in hypertensives and normals (5.0±0.6 and 5.2±1.1 mg·liter⁻¹·min⁻¹, respectively).
  • Forearm NE balance increased fourfold in hypertensives during systemic hyperinsulinemia (P < 0.05), whereas it was statistically indistinguishable from zero in normals.

Methods

  • Forearm perfusion technique with tritiated norepinephrine tracer was used in 45 subjects: 21 normotensives and 24 patients with mild to moderate essential hypertension.
  • Two protocols: systemic insulin infusion at 1 mU/kg per min for 120 min with euglycemia (12 normals, 14 hypertensives), or local intrabrachial insulin at 0.05 mU/kg per min (9 normals, 10 hypertensives); tracer subgroups received [³H]norepinephrine.
  • Forearm NE kinetics were calculated from arterial–venous balance, fractional extraction, clearance, uptake, and release; comparisons used paired and unpaired t tests, with values reported as mean±SE.

Limitations

  • The paper states that it cannot answer whether hyperinsulinemia is the primary defect leading to hypertension via sympathetic overactivity, and that an alternative primary sympathetic overactivity causing both hypertension and insulin resistance would be equally compatible with the data.
  • The paper states that the mechanism of insulin-evoked muscle sympathetic overactivity is unknown and that a peripheral reflex such as a venous baroreflex or chemoreflex cannot be excluded.
  • Evident from the text: sample sizes are small, especially for tracer subgroups (e.g., 8 normals and 7 hypertensives for systemic tracer studies; 5 and 5 for local tracer studies), and the local infusion model relies on adequate mixing, which was assessed in only 16 tested cases.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1172/jci115842

Cites

50 of 50 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

0 of 35 cited sources checked · 0 supported · 0 flagged

Show all 43 claims

  • It may state two separate claims as one. 17
  • Probably not a substantial claim. 8
24 of 24
  • The paper relies on this without support.

    The reason why hyperinsulinemia is associated with essential hypertension is not known.

    “The reason why hyperinsulinemia is associated with essential hypertension is not known.”
  • The paper relies on this without support.

    The available clinical data support the concept that insulin and human hypertension must be linked by pathophysiologic mechanisms.

    “The available clinical data, however, tend to support the concept that the two factors must be linked by pathophysiologic mechanisms.”
  • The paper relies on this without support.

    The effluent venous blood from the deep antecubital vein drains predominantly muscle tissue.

    “Under these conditions, the effluent venous blood drained predominantly muscle tissue.”
  • The paper relies on this without support.

    Forearm norepinephrine release measured by the [3H]norepinephrine infusion technique reflects skeletal muscle sympathetic nerve activity.

    “In conclusion, the current study provides evidence for an abnormal muscle sympathetic activity reflexly evoked by insu- lin in essential hypertension.”
4 of 4

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • NE-release calculation has its subtraction reversed

    Minor

    Under the paper's stated sign convention, net NE balance is uptake minus release. Release therefore equals uptake minus net balance, not net balance minus uptake as the calculation describes.

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Metadata

Authors
Lembo, G., Napoli, R., Capaldo, B., Rendina, V, Iaccarino, G., Volpe, M., Trimarco, B., & Saccà, L.
Affiliations
Federico II University Hospital (IT)
Venue
Journal of Clinical Investigation
Published
1992-07-01
Volume
90
Issue
1
Pages
24-29
ISSN
0021-9738 (ISSN-L)
OpenAlex
W2159417090
Cited by
252
References
47
Citations by year
2026: 1 · 2025: 10 · 2024: 6 · 2023: 8 · 2022: 6 · 2021: 5 · 2020: 6 · 2019: 3 · 2018: 9 · 2017: 3 · 2016: 9 · 2015: 5 · 2014: 6 · 2013: 4 · 2012: 8
FWCI
12.48
Type
journal article
Language
en
Open access
Locations
  • Journal of Clinical Investigation (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • IRIS Research product catalog (Sapienza University of Rome) (submittedVersion)
Funders
Società Italiana dell'Ipertensione Arteriosa
Topics
  • Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Blood Pressure and Hypertension Studies
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes, Cardiovascular Risks, and Lipoproteins
  • Health Sciences › Medicine › Physiology (medical) › Nitric Oxide and Endothelin Effects
Keywords
essential hypertension, hyperinsulinemia, insulin resistance, skeletal muscle, sympathetic nervous system, noradrenaline release, glucose uptake
MeSH terms
Adult, Female, Humans, Hypertension, Insulin, Male, Muscles, Norepinephrine, Sympathetic Nervous System

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