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The brain renin‐angiotensin system suppresses digestive efficiency (1126.13)
Author(s) -
Weidemann Benjamin,
Littlejohn Nicole,
Cole Renee,
Grobe Justin
Publication year - 2014
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.28.1_supplement.1126.13
Subject(s) - endocrinology , medicine , renin–angiotensin system , chemistry , angiotensin ii , receptor , adipose tissue , biology , blood pressure
The renin‐angiotensin system (RAS) contributes to metabolic control through local actions within the brain and adipose. All components of the RAS are also expressed in the gastro‐intestinal (GI) tract, leading to the hypothesis that the RAS controls digestive efficiency. Mice with transgenic hyperactivity of the brain RAS (sRA) were generated through neuron‐specific expression of human renin, and expression of human angiotensinogen via its own promoter. sRA exhibit reduced body mass and elevated resting metabolic rate through elevated sympathetic nervous activity and a chronic suppression of the circulating RAS. Caloric densities of food/feces were assessed by bomb calorimetry. sRA had increased caloric intake (15.4±0.7 kcal/day, n=8) vs littermate control mice (13.0±0.7, n=7, P<0.01) as well as an increase in caloric loss to feces (6.3±0.8 vs 2.9±0.4 kcal/day, P<0.01). Thus, sRA had decreased digestive efficiency (59±5 vs 78±2 %, P<0.01) versus littermates on chow diet (Teklad 7013), but total daily caloric absorption (9.1±0.8 vs 10.0±0.5 kcal/day, P=0.36) was normal. Infusion of the angiotensin (Ang) II type 2 receptor agonist CGP‐42112a (50 ng/kg/min, s.c., 8 weeks) had no effect on efficiency or absorption (sRA 63±6 vs control 80±1 %; 9.3±0.8 vs 9.8±1.0 kcal/day). We conclude that the brain and circulating RAS help control digestive efficiency, and hypothesize a role for GI tract Ang II type 1 receptors. Grant Funding Source : Supported by NIH: HL098276, HL084207.