The effects of catecholamines on antidiuretic hormone ([Arg8]-vasopressin [AVP])-induced water absorption were evaluated in cortical collecting tubules isolated from the rabbit kidney and perfused in vitro. In the presence of AVP (100 μU/ml), net fluid volume absorption (Jv, nanoliters per minute per millimeter) was 1.14±0.12 and osmotic water permeability coefficient (Pf, X 10-4 centimeters per second) was 217.3±39.9. The addition of the alpha-adrenergic agonist, phenylephrine (PE), in a concentration of 10-6 M resulted in a significant decrease in Jv and Pf to 0.83±0.13 (P < 0.001) and 148.8±41.8 (P < 0.02), respectively. Increasing the concentration of PE to 10-5 M resulted in a further decrease in Jv and Pf to 0.53±0.05 (P < 0.05 vs. PE 10-6 M) and 88.5±9.0 (P 0.05 vs. PE 10-6 M), respectively. In a separate group of tubules, in the presence of AVP (100 μU/ml) and PE (10-5 M), Jv and Pf were 0.35±0.07 and 66.0±17.3, respectively. The addition of the alpha-adrenergic antagonist, phentolamine (PH), in a concentration of 10-6 M resulted in a significant increase in Jv to 1.07±0.19 (P < 0.001) and Pf to 193.3±35.9 (P < 0.005). PH (10-5 M) alone did not significantly affect Jv and Pf in the presence of AVP (100 μU/ml) nor in the presence of 8-bromo adenosine 3',5' cyclic monophosphate (8-BrcAMP). Jv and Pf were 1.20±0.21 and 174.0±25.8, respectively, in the presence of 8-BrcAMP (10-4 M).
Radha K. Krothapalli, W. Brian Duffy, Harry O. Senekjian, Wadi N. Suki
Usage data is cumulative from September 2025 through September 2026.
| Usage | JCI | PMC |
|---|---|---|
| Text version | 287 | 9 |
| 126 | 0 | |
| Scanned page | 580 | 6 |
| Citation downloads | 202 | 0 |
| Totals | 1,195 | 15 |
| Total Views | 1,210 | |
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.