## 3 Results
### Tissue RAS-Regulating Enzyme Activities  
#### 3.7.1 Renal Cortex  
Figure 11 illustrates the specific activities of soluble and membrane-bound RAS-regulating enzymes in the renal cortex of the different groups in WKY and SHRs. Figure 11A shows the ACE activity, where a significant increase (\(p<0.05\)) is observed in the TW/NAB group in WKY animals and a significant decrease (\(p<0.05\)) is observed in the TW/NAB group in SHRs. In Figure 11B,C, the APA activity is presented in soluble and membrane-bound forms, respectively. Soluble APA shows a significant increase (\(p<0.01\)) in the NAB group compared to TW, with a similar rise (\(p<0.01\)) in the TW/NAB group in SHRs. In WKY animals, increased APA activity was also found in the NAB group, whereas a decrease occurs in the AB group (\(p<0.01\)). In the membrane-bound form, the TW/AB group shows a significant increase (\(p<0.01\)) in APA activity compared to the TW and TW/NAB groups in SHRs. No significant changes were observed in WKY animals. Figure 10: (**A**) Angiotensin-converting enzyme (ACE) activity, and specific activities of aminopeptidase A (APA) (**B**), aspartyl aminopeptidase (ASAP) (**C**), aminopeptidase N (APN) (**D**), and aminopeptidase B (AFB) (**E**) in the serum of Wistar–Kyoto rats (WKY) and spontaneously hypertensive rats (SHRs). Experimental groups included animals provided with tap water (TW), alcohol-free beer (NAB), tap water or alcohol-free beer at their discretion (TW/NAB), alcoholic beer (AB), or tap water and alcoholic beer at their discretion (TW/AB). Results are presented as ACE activity in IU/L, and for APA, ASAP, APN and APB, in picomoles of the corresponding aminoacyl-B-naphthylamide hydrolyzed per minute per milligram of protein (mean \(\pm\) SEM; n = 8; \({}^{*}\)\(p<0.05\); \({}^{**}\)\(p<0.01\)). Figure 11: (**A**) Angiotensin-converting enzyme (ACE) activity, and specific activities of soluble (**B**) and membrane-bound (**C**) aminopeptidase A (APA), soluble (**D**) and membrane-bound (**E**) aspartyl aminopeptidase (ASAP), soluble (**F**) and membrane-bound (**G**) aminopeptidase N (APN), and soluble (**H**) and membrane-bound (**I**) aminopeptidase B (APB) in the renal cortex of Wistar–Kyoto rats (WKY) and spontaneously hypertensive rats (SHRs). Experimental groups included animals provided with tap water (TW), alcohol-free beer (NAB), tap water or alcohol-free beer at their discretion (TW/NAB), alcoholic beer (AB), or tap water and alcoholic beer at their discretion (TW/AB). Results are presented as ACE activity in IU/L, and for APA, ASAP, APN and APB, in picomoles of the corresponding aminoacyl-\(\beta\)-naphthyl hydrolyzed per minute per milligram of protein (mean \(\pm\) SEM; n = 8; * \(p<0.05\); ** \(p<0.01\)). Figure 11D shows that ASAP activity in its soluble form is not detectable (ND) across all groups. However, in the membrane-bound form (Figure 11E), there is a significant elevation of ASAP activity in the TW/AB group (\(p\) < 0.01) compared to the TW and TW/NAB groups in SHRs, whereas in WKY animals, a significant decrease occurs after receiving NAB, AB and TW/AB (\(p\) < 0.05 and \(p\) < 0.01, respectively). The APN activity, shown in Figure 11, demonstrates significant differences in both its soluble and membrane-bound forms. In the soluble form (Figure 11F), a significant increase (\(p\) < 0.05) is observed in the TW/AB group in SHR, whereas a significant decrease (\(p\) < 0.05) occurs in the AB group of WKY animals. In the membrane-bound form (Figure 11G), significant decreased levels appear in the NAB (\(p\) < 0.05), TW/NAB (\(p\) < 0.01) and AB groups (\(p\) < 0.05) in WKY animals, whereas the highest levels of APN occur in the TW/AB group in SHRs. Finally, Figure 11H,I show the APB activity. In the soluble form, a significant increase (\(p\) < 0.01) is observed in the TW/AB group compared to the AB group, only in WKY animals.