This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
Decrease in contributing factor in chronic hypeension is associated with 
Select and explain. 
A. Aldosterone, B. Angiotensin II, C. Nitric oxide, D. Reduced sympathetic nerve
C: Nitric oxide
Answer: C: Nitric oxide 
Explanation: Twofold increase in plasma TNF-alpha levels in pregnant rats resulted in a significant increase in aerial pressure (97 +/- 3.6 v 116 +/- 2.1 mm Hg, pregnant versus TNF-alpha pregnant, respectively, P < .05), but no significant change in urinary nitrite/nitrate excretion (22.0 +/- 1.9 v 20.8 +/- 2.5 micromol/24 h, pregnant versus TNF-alpha pregnant, respectively), a measure of whole-body NO production.