Usage Information
Abstract
It has been suggested that collecting duct sodium transport was inhibited by extracellular volume expansion. To directly evaluate this possibility, micropuncture of the papillary collecting duct of young rats was performed during hydropenia and Ringer loading. The possibility of heterogeneity of nephron function was evaluated during Ringer and hyperoncotic albumin loading by comparing the delivery of sodium to the end of the distal tubule of superficial nephrons with papillary base delivery. During hydropenia (n = 14), sodium delivery to the base averaged 0.95% of the filtered sodium load and reabsorption along the collecting duct was noted from base to tip in each collection pair averaging 0.80% of the filtered load. During Ringer loading, sodium delivery to the base was markedly greater than in hydropenia, 11.8 vs. 0.95% of the filtered load (P less than 0.001). Yet, sodium reabsorption was also much greater, 6 vs. 0.8% (P less than 0.001). In 13 paired collections, during Ringer loading, sodium delivery to the papillary base, 12.2% of the filtered load, was consistently greater than late distal tubular delivery from superficial nephrons. 8% (P less than 0.005). In contrast, reabsorption of sodium from late distal tubule to papillary base was found during albumin infusion, 6.2 vs. 3.1% (P less than 0.001). Therefore, these studies demonstrate that: (a) the delivery of sodium to and reabsorption along the papillary collecting duct were markedly greater during Ringer loading than in hydropenia; (b) the amount of sodium delivered to the papillary base was greater than the delivery to the end of the distal tubule of superficial nephrons during Ringer loading, suggesting that deeper nephrons deliver more sodium to the collecting duct in this setting; and (c) the difference in sodium excretion between Ringer loading and hyperoncotic albumin infusion is due to events occurring between the late distal tubule of superficial nephrons and the base of the papillary collecting duct.
Authors
J H Stein, R W Osgood, R T Kunau Jr
Usage data is cumulative from May 2025 through May 2026.
| Usage | JCI | PMC |
|---|---|---|
| Text version | 215 | 3 |
| 93 | 5 | |
| Scanned page | 373 | 4 |
| Citation downloads | 168 | 0 |
| Totals | 849 | 12 |
| Total Views | 861 | |
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.
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)