Refeeding reverses cardiac myosin shifts induced by undernutrition in aged rats: Modulation by growth hormone

Bill T. Ameredes, Monica J. Daood, Jon F. Watchko

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Growth hormone (GH) was administered (1 mg/day, i.p., 7.5 months) to male Fischer 344 rats, in conjunction with refeeding (RF) after chronic undernutrition (UN), from middle age (17 months old) to senescence (24.5 months old), during which cardiac myosin heavy chain (MHC) profiles were determined by gel-electrophoresis. At 17 months of age, respective MHC-α and -β composition was 74 and 26% in the right: ventricle (RV), and 58 and 42% in the left ventricle (LV), of ad libitum-fed controls. At 24.5 months of age, MHC profiles of controls were shifted toward the MHC-β isoform in both RV (α = 53%, β = 47%) and LV (α = 40%, β= 60%), indicating a significant effect of aging on MHC composition in both ventricles. At 17 months of age, 7.5 months of UN likewise resulted in a shift toward the MHC-β isoform in both RV (α = 31%, β = 69%) and LV (α = 22%, β = 78%) as compared to controls, indicating a significant effect of UN in both ventricles. Continued UN into senescence maintained these altered profiles in both ventricles, at 24.5 months of age (RV: α = 35%, β = 65%; LV: α = 24%, β = 76%). RF + GH administered from middle age into senescence restored the MHC composition in both ventricles (RV: α = 57%, β = 43%; LV: α = 43%, β = 57%), to that of the controls. RF, alone, likewise reversed ventricular MHC composition toward that of MHC-α, but appeared to overcompensate (RV: α = 67%, β = 33%; LV: α = 46%, β = 54%), surpassing the control and RF + GH profiles, significantly in the RV. These data suggest that GH is a modulator of restoration of cardiac MHC composition, when RF is administered to counter the effects of chronic UN, in the aging rat heart.

Original languageEnglish (US)
Pages (from-to)1525-1533
Number of pages9
JournalJournal of Molecular and Cellular Cardiology
Volume30
Issue number8
DOIs
StatePublished - Aug 1998
Externally publishedYes

Keywords

  • Contractile proteins
  • Heart
  • Nutritional repletion
  • Right-ventricular hypertrophy
  • Thyroid
  • Tri-iodothyronine

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

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