Key result
Transgenic rats overexpressing the human renin gene developed moderate obesity, increased body fat mass, and glucose intolerance compared with nontransgenic controls, independent of angiotensin II.
Why the study?
Does overexpression of the human renin gene alter energy metabolism and body weight in rats independently of angiotensin II?
Does overexpression of the human renin gene alter energy metabolism and body weight in rats independently of angiotensin II?
The human renin transgene initiates early appetite increase, obesity, and metabolic changes in rats through mechanisms independent of angiotensin II.
Findings in transgenic rats do not alter clinical management; leaves open whether renin drives human metabolic dysfunction independently of angiotensin II.
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.
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Gratze et al. (2009) studied Obesity and energy metabolism. Human renin gene (hREN) overexpression vs. Nontransgenic Sprague-Dawley (SD) rats was evaluated on Obesity, body fat mass, and glucose intolerance. Transgenic rats overexpressing the human renin gene developed moderate obesity, increased body fat mass, and glucose intolerance compared with nontransgenic controls, independent of angiotensin II.