Table 2.

Water balance measures during intravenous infusions of ANG II under control and reduced pressure conditions in young (4 mo), middle-aged adult (12 mo), and old (29 mo) rats

	Control Pressure Condition			Reduced Pressure Condition
Age, mo	4	12	29	4	12	29
Absolute Measures, ml
Intake	3.5 ± 0.8	6.6 ± 0.6*	7.1 ± 0.7*	5.8 ± 0.6‡	7.7 ± 0.7*	6.8 ± 1.1*
Urine	6.2 ± 0.5	6.9 ± 0.8	10.6 ± 1.1†	0.9 ± 0.4‡	2.2 ± 0.7‡	2.6 ± 0.7†‡
Balance	−2.7 ± 0.6	−0.3 ± 0.4†	−3.5 ± 1.5	4.9 ± 0.7‡	5.5 ± 0.6†‡	4.4 ± 1.0‡
Body Weight-Adjusted Measures, ml/100 g
Intake	1.1 ± 0.3	1.8 ± 0.2	1.6 ± 0.2	1.9 ± 0.2‡	1.9 ± 0.2	1.5 ± 0.2
Urine	2.0 ± 0.1	1.7 ± 0.2	2.3 ± 0.2	0.3 ± 0.1‡	0.5 ± 0.2‡	0.6 ± 0.2‡
Balance	−0.9 ± 0.2	−0.0 ± 0.1	−0.7 ± 0.3	1.6 ± 0.2‡	1.4 ± 0.2‡	0.9 ± 0.2‡*

Values are means ± SE. Water intake, urine volume, and water balance measures over 3 h of infusion with ANG II. Balance measures do not include ∼2.4 ml of infusion volume. There were main effects of age for all absolute measures, but not for body weight-adjusted measures.

^*Significantly different from young rats, P <0.05;

^†significantly different from both the other groups, P <0.05;

^‡significantly different from control values, P <0.05.