Effects of high-fat vs. low-fat diets on mammalian target of rapamycin signaling and metabolic measures in spontaneously hypertensive rats

Update Item Information
Publication Type thesis
School or College College of Health
Department Nutrition & Integrative Physiology
Author Bosse, John David
Title Effects of high-fat vs. low-fat diets on mammalian target of rapamycin signaling and metabolic measures in spontaneously hypertensive rats
Date 2010-12
Description Preliminary studies in the Division of Nutrition;'s Nutrition; Sciences lab have shown that spontaneously hypertensive rats (SHRs) fed high-fat diets (HF; 60% kcals) have a reduction in cardiac mammalian target of rapamycin (mTOR) signaling, with no impairments in whole body insulin tolerance. Having previously demonstrated that suppression of mTOR decreased cardiac hypertrophy, it was hypothesized that an HF diet would decrease cardiac hypertrophy, without causing insulin resistance or altering insulin-stimulated mTOR signaling. Forty-eight 5-week-old rats (SHR n = 24; Wistar Kyoto (WKY; normotensive control) n = 24) were randomly assigned to consume an HF or low-fat (LF) diet (10% kcals). After 10 weeks, cardiac hypertrophy was similar in SHRHF vs. SHRLF. Insulin stimulation increased (p < 0.05) phosphorylation of heart and gastrocnemius Akt (Ser473) and S6 (Ser235/236) regardless of genotype or diet with SHRHF responding more robustly (p < 0.05) than WKYHF. Fat pad mass was 37% greater in WKYHF vs. WKYLF, but only 20% greater in SHRHF vs. SHRLF. Similarly, plasma leptin was ~70% greater in WKYHF vs. WKYLF, but unchanged in SHRHF vs. SHRLF. Plasma adiponectin was reduced (p < 0.05) in SHRHF vs. both WKY groups. In conclusion, while an HF diet did not prevent cardiac hypertrophy in SHRs, it also did not cause diet-induced insulin resistance, hyperleptinemia, or weight gain with only a modest increase in adiposity. In contrast to previous thinking, an HF diet may enhance insulin-stimulated mTOR signaling in SHRs.
Type Text
Publisher University of Utah
Subject Cardiac hypertrophy; Hypertension; Protein synthesis; High-fat diet; Microbiology; Nutrition; Physiology
Subject LCSH Heart -- Hypertrophy -- Nutrition;al aspects; Rapamycin; Low-fat diet
Dissertation Institution University of Utah
Dissertation Name MS
Language eng
Rights Management © John David Bosse
Format Medium application/pdf
Format Extent 314,506 bytes
Source Original in Marriott Library Special Collections, RC39.5 2010 .B67
ARK ark:/87278/s66h4xxb
Setname ir_etd
ID 192687
Reference URL https://collections.lib.utah.edu/ark:/87278/s66h4xxb