Energy metabolism in human renin-gene transgenic rats: does renin contribute to obesity?
Renin initiates angiotensin II formation and has no other known functions. We observed that transgenic rats (TGR) overexpressing the human renin gene (hREN) developed moderate obesity with increased body fat mass and glucose intolerance compared with nontransgenic Sprague-Dawley (SD) rats. The metabolic changes were not reversed by an angiotensin-converting enzyme inhibitor, a direct renin inhibitor, or by (pro)renin receptor blocker treatment. The obese phenotype in TGR(hREN) originated from higher food intake, which was partly compensated by increases in resting energy expenditure, total thermogenesis (postprandial and exercise activity), and lipid oxidation during the first 8 weeks of life. Once established, the difference in body weight between TGR(hREN) and SD rats remained constant over time. When restricted to the caloric intake of SD, TGR(hREN) developed an even lower body weight than nontransgenic controls. We did not observe significant changes in the cocaine and amphetamine-regulated transcript, pro-opiomelanocortin, both anorexigenic, or neuropeptide Y, orexigenic, mRNA levels in TGR(hREN) versus SD controls. However, the mRNA level of the agouti-related peptide, orexigenic, was significantly reduced in TGR(hREN) versus SD controls at the end of the study, which indicates a compensatory mechanism. We suggest that the human renin transgene initiates a process leading to increased and early appetite, obesity, and metabolic changes not related to angiotensin II. The mechanisms are independent of any currently known renin-related effects.
Gratze
Petra
P
Franz Volhard Clinical Research Center, HELIOS Klinikum Berlin-Buch, Berlin-Buch, Germany.
Boschmann
Michael
M
Dechend
Ralf
R
Qadri
Fatimunnisa
F
Malchow
Jeanette
J
Graeske
Sabine
S
Engeli
Stefan
S
Janke
Jürgen
J
Springer
Jochen
J
Contrepas
Aurelie
A
Plehm
Ralph
R
Klaus
Susanne
S
Nguyen
Genevieve
G
Luft
Friedrich C
FC
Muller
Dominik N
DN
D017667:Adipocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D000577:Amides / Q000494:pharmacology; D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004734:Energy Metabolism / Q000502:physiology*; D005650:Fumarates / Q000494:pharmacology; D006801:Humans; D020738:Leptin / Q000097:blood; D050356:Lipid Metabolism / Q000502:physiology; D008297:Male; D009765:Obesity / Q000378:metabolism*; D010641:Phenotype; D051381:Rats; D017207:Rats, Sprague-Dawley; D055647:Rats, Transgenic; D012083:Renin / Q000235:genetics / Q000378:metabolism*; D022722:Thermogenesis / Q000502:physiology; D000092502:Renin Inhibitors
D000577:Amides; D000804:Angiotensin II; D005650:Fumarates; D020738:Leptin; D012083:Renin; D000092502:Renin Inhibitors; C446481:aliskiren