MODULATION OF TISSUE ANGIOTENSINOGEN GENE-EXPRESSION IN GENETICALLY-OBESE HYPERTENSIVE RATS

Wistar fatty rats (WFR) show obesity and obesity-related features, inc luding hypertension. In this study, we examined the expression of angi otensinogen mRNA in a variety of tissues at different times in WFR and control Wistar lean rats (WLR). WFR were obese and hypertensive at 16 and 24 wk. Plasma renin activity and plasma angiotensinogen concentra tion showed age-dependent increases in WFR but decreases in WLR. North ern blot analysis showed no significant differences in the levels of h epatic and renal angiotensinogen mRNA between WFR and WLR, and the lev els of fat and adrenal angiotensinogen mRNA were lower in WFR than in WLR. On the other hand, the levels of cardiac angiotensinogen mRNA at 16 and 24 wk and those of aortic angiotensinogen mRNA at 16 wk were si gnificantly higher in WFR than in WLR. These results show that the exp ression of tissue angiotensinogen mRNA is regulated differently in WFR and WLR and indicate that the development of hypertension in WFR is a ccompanied at least temporally with increases in plasma angiotensinoge n concentration as well as in cardiac and aortic angiotensinogen mRNA. Moreover, these results suggest the existence of obesity hypertension -linked and tissue-specific regulation of angiotensinogen gene express ion.