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Adrenalectomy Corrects α‐adrenergic Hyperreactivity in Obese Zucker Rats
Author(s) -
Mintz James D.,
Lehn Robert A.,
Stepp David W.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a480-b
Subject(s) - endocrinology , medicine , hindlimb , adrenalectomy , corticosterone , adrenergic , phenylephrine , stimulation , chemistry , receptor , blood pressure , hormone
Obesity is a risk factor for cardiovascular disease. We have demonstrated that skeletal muscle resistance arteries are hyperreactive to adrenergic (ADR) stimulation but the mechanism is unknown. Because ADR receptor expression is regulated by glucocorticoids, this study tested the hypothesis that clamping corticosterone concentrations would correct ADR hypersensitivity. Lean (LZR) and Obese Zucker rats (OZR) (15–20 weeks of age) were subjected to adrenalectomy with salt balance preserved by saline and corticosterone clamped at 1 mg/day (AXC). After 3 weeks, changes in mesenteric and hindlimb blood flow were assessed in response to phenylephrine (PHE) under isoflurane anesthesia. Intact OZR were hypertensive (124±9 vs. 109±6) compared to LZR and ACX eliminated this difference. Hindlimb responses to PHE were increased in OZR vs. LZR (133±14 vs. 207±23 %) and ACX eliminated this difference. Mesenteric responses to PHE were decreased in OZR vs. LZR (828±263 vs. 420±141 %) and ACX had no effect on this difference. These data suggest that adrenal steroids contribute to the changes in vascular reactivity observed in the hindlimb circulation of OZR. (HL76533 to DWS)