The Effect of Renal Artery Constriction on Tubular Reabsorption of Bicarbonate
Bibliographic record
Abstract
Tubular reabsorption of bicarbonate was studied in the normal dog after bilateral constriction of the renal arteries (Goldblatt clamp) during sodium bicarbonate loading (mean plasma bicarbonate 35 mM/l and urinary pH 7.58). Reduction of glomerular filtration rate averaged 45% of control. Following acute constriction of the renal arteries (21 animals) bicarbonate reabsorption rose slightly from 2.6 to 2.9 mM/100 ml GFR. More striking however was the direct relationship between the fall in filtration rate and the absolute rate of tubular reabsorption (mM/min). Similar findings were observed in 11 animals after 14 days of sustained constriction of the renal arteries. In 7 additional experiments plasma bicarbonate concentration was elevated above 50 mM/l after acute clamping of the renal arteries in order to maintain filtered bicarbonate near control level. In these experiments bicarbonate reabsorption remained at 2.8 mM/100 ml GFR while the absolute rate of reabsorption (mM/min) decreased. In another series of 6 experiments during acute unilateral clamping of the left renal artery, results on the affected side were identical to those observed following bilateral constriction. The present study supplies evidence that bicarbonate reabsorption is not governed by a true Tm mechanism following acute or chronic reduction of glomerular filtration rate. It thus supports the concept that variations in glomerular filtration rate influence bicarbonate reabsorption in such a manner that bicarbonate concentration is kept relatively constant in the extracellular fluid.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".