## 3 Results
### Tissue RAS-Regulating Enzyme Activities
#### 3.7.5 Anterior Pituitary  
Figure 15 demonstrates the effects of the various treatments on RAS-regulating specific enzymatic activities in the anterior pituitary of WKY and SHRs after receiving TW, NAB, TW/NAB, AB and TW/AB.  
ACE activity only shows a significant increase in SHRs in the TW/AB treatment (\(p\) > 0.05). However, the differences between WKY and SHRs across treatments are minimal (Figure 15A).  
The APA activity shows significant changes in both soluble and membrane-bound fractions. Soluble APA activity (Figure 15B) decreases significantly in all beverage groups when compared with TW in WKY animals (\(p\) < 0.01), with the lower value being in rats receiving NAB. On the contrary, in SHRs, only animals receiving TW/NAB have significant increases in their APA activity when compared with the NAB group (\(p\) < 0.05). Membrane-bound APA only showed significant differences in WKY animals (\(p\) < 0.01), with a similar trend to that seen in the soluble form (Figure 15C).  
For the soluble ASAP specific activity, WKY animals receiving NAB showed the lowest significant difference (\(p\) < 0.01) compared to animals receiving TW and TW/NAB. In SHRs, animals receiving TW/NAB showed the highest values compared to the other treatments (\(p\) < 0.05; Figure 15D). In the membrane-bound fraction, WKY animals showed significantly decreased levels of ASAP after receiving NAB and TW/AB (\(p\) < 0.05 in both cases). On the contrary, in SHRs, membrane-bound ASAP significantly decreased in animals receiving NAB (\(p\) < 0.01), TW/NAB (\(p\) < 0.05) and AB (\(p\) < 0.05), but not TW/AB (Figure 15E).  
The APN activity also shows substantial variability. In WKY animals, the soluble specific APN activity significantly decreased in animals receiving NAB (\(p\) < 0.01) and TW/NAB (\(p\) < 0.05) (Figure 15F). In SHRs, animals receiving TW/AB showed the highest values, with significant differences (\(p\) < 0.01 and \(p\) < 0.05, respectively) compared to animals receiving TW or AB. In the membrane-bound fraction, both WKY and SRHs showed significantly decreased values of APN specific activity in all groups when compared to animals receiving TW (Figure 15G).  
The soluble APB specific activity showed substantial changes across treatments in both WKY and SHRs. Thus, in WKY animals, significant decreases were found in rats receiving NAB and TW/NAB (\(p\) < 0.05 in both cases). In SHRs, on the contrary, the soluble specific APB activity increased significantly in animals receiving TW/NAB, AB and TW/AB (\(p\) < 0.05 and \(p\) < 0.01) compared to those receiving TW (Figure 15H). For the membrane-bound specific APB activity, significant changes only appeared in WKY animals receiving NAB (\(p\) < 0.01), TW/NAB (\(p\) < 0.01), AB (\(p\) < 0.05) and TW/AB (\(p\) < 0.01) when compared to animals receiving TW alone (Figure 15I).  
Figure 15: (**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 anterior pituitary 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-\(\beta\)-naphthyllamide hydrolyzed per minute per milligram of protein (mean \(\pm\) SEM; \(n\) = 8; \({}^{*}\)\(p<0.05\); \({}^{**}\)\(\ast\)\(p<0.01\)).