Study of acute pharmacologic effects of prolactin on calcium and water transport in the rat colon by an in vivo perfusion technique
Bibliographic record
Abstract
We investigated the acute effect of intraperitoneally administered prolactin on calcium and water transport in colon of sexually mature female Wistar rats using an in vivo perfusion technique. Test solution containing (in mM) NaCl, 100; KCl, 4.7; MgSO 4 , 1.2; CaCl 2 , 20; D-glucose, 11; sodium ferrocyanide (Na 4 Fe(CN) 6 ), an index of net water transport, 20; and 0.7 (µCi 45 CaCl 2 (1 Ci = 37 GBq) was perfused througth the 8-cm colonic loop for 60 min at perfusion rates of 0.5 or 1.0 mL·min 1 . Calcium and water transport was also studied under a no flow condition to stimulate the condition often found in the colon by in vivo ligated colonic loop for 30 min. Control results showed no correlation between calcium transport and water flux. Flow of luminal solution at 0.5 and 1.0 mL·min 1 was found to reverse net calcium absorption from 0.04 ± 0.01 nmol·g 1 dry weight·h 1 to net calcium secretion of 0.04 ± 0.04 and 0.9 ± 0.02 nmol·g 1 dry weight·h 1 , respectively. Neither 0.4, 0.6, nor 1.0 mg·kg 1 prolactin had any effect on calcium fluxes in the colon. On the other hand, at a perfusion rate of 1 mL·min 1 , 0.4 mg·kg 1 prolactin significantly decreased net water absorption from 3.86 ± 0.90 to 0.88 ± 0.64 mL·g 1 dry weight·h 1 (P < 0.001), and the higher doses of 0.6 and 1.0 mg·kg 1 prolactin reversed net water absorption to net water secretion of 2.20 ± 0.63 and 2.33 ± 0.89 mL·g 1 dry weight·h 1 , respectively (P < 0.001). The stimulatory effect of prolactin on water transport was completely abolished by reducing the perfusion rate from 1.0 mL·min 1 to zero. The stimulatory effect of prolactin on water secretion at perfusion rate of 1.0 mL·min 1 was also abolished when luminal [Na + ] was reduced from 180 to 80 mM. We concluded that, unlike in the small intestine, calcium fluxes in the colon are not related to water transport and did not respond at all to prolactin. Water transport, on the other hand, was reversed from net absorption to secretion by prolactin. We propose that this prolactin-induced water secretion is probably mediated by recycling of luminal sodium in the vicinity of tight junctions.Key words: calcium fluxes, colon, perfusion technique, prolactin, water transport.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".