Adipose tissue renin levels did not correlate with plasma renin except at extremely high concentrations, suggesting adipose tissue controls its own local renin concentration independently of plasma.
Does variation in plasma renin and angiotensinogen concentrations influence local adipose and cardiac tissue levels in an in vivo rat model?
Adipose tissue appears to regulate its own local renin concentration independently of plasma renin levels, supporting the existence of a functional local adipose renin-angiotensin system.
The renin-angiotensin system (RAS) has been implicated in a variety of adipose tissue functions, including tissue growth, differentiation, metabolism, and inflammation. Although expression of all components necessary for a locally derived adipose tissue RAS has been demonstrated within adipose tissue, independence of local adipose RAS component concentrations from corresponding plasma RAS fluctuations has not been addressed. To analyze this, we varied in vivo rat plasma concentrations of two RAS components, renin and angiotensinogen (AGT), to determine the influence of their plasma concentrations on adipose and cardiac tissue levels in both perfused (plasma removed) and nonperfused samples. Variation of plasma RAS components was accomplished by four treatment groups: normal, DOCA salt, bilateral nephrectomy, and losartan. Adipose and cardiac tissue AGT concentrations correlated positively with plasma values. Perfusion of adipose tissue decreased AGT concentrations by 11.1%, indicating that adipose tissue AGT was in equilibrium with plasma. Cardiac tissue renin levels positively correlated with plasma renin concentration for all treatments. In contrast, adipose tissue renin levels did not correlate with plasma renin, with the exception of extremely high plasma renin concentrations achieved in the losartan-treated group. These results suggest that adipose tissue may control its own local renin concentration independently of plasma renin as a potential mechanism for maintaining a functional local adipose RAS.
Fowler et al. (Tue,) reported a other. Variation of plasma RAS components (DOCA salt, bilateral nephrectomy, losartan) vs. Normal was evaluated on Adipose and cardiac tissue renin and angiotensinogen (AGT) concentrations. Adipose tissue renin levels did not correlate with plasma renin except at extremely high concentrations, suggesting adipose tissue controls its own local renin concentration independently of plasma.