Renal excretion of urea in the salamander, Ambystoma tigrinum
| Autor: | Daniel F. Stiffler, C. Terrance Hawk, Beth C. Fowler |
|---|---|
| Rok vydání: | 1980 |
| Předmět: |
medicine.medical_specialty
Hypophysectomy medicine.medical_treatment Inulin Urodela Nephron Biology Kidney chemistry.chemical_compound Internal medicine medicine Animals Urea Reabsorption fungi General Medicine Phlorhizin medicine.anatomical_structure Endocrinology chemistry Larva Renal physiology p-Aminohippuric Acid Animal Science and Zoology Dinitrophenols Antidiuretic |
| Zdroj: | Journal of Experimental Zoology. 213:205-212 |
| ISSN: | 1097-010X 0022-104X |
| DOI: | 10.1002/jez.1402130207 |
| Popis: | Renal excretion of urea was assessed in adult and larval Ambystoma tigrinum by comparing simultaneous clearances of urea and inulin. The mean adult urea clearance ratio (Cu/CIn) was 0.70 ± 0.08 indicating net urea absorption. Larvae yielded a mean CU/CIn) of 0.92 ± 0.04. Individual larvae were quite variable however as approximately 30% displayed CU/CIn>1. There was a significant negative correlation between CU/CIn and fractional water reabsorption. Comparisons of larval kidney urea concentration (KU) and plasma urea concentration (PU) revealed a mean KU/PU of 1.43 ± 0.15. Treatment with 2,4-dinitrophenol decreased larval CU/CIn to 0.80 ± 0.05 and KU/PU to 0.91 ± 0.08. Phloridzin also decreased CU/CIn (0.67 ± 0.06) however para-aminohippuric acid had no effect. Hypophysectomy combined with cautery of the pituitary stalk resulted in CU/CIn of 1.71 ± 0.33 as compared to 0.84 ± 0.08 in shams. These results are consistent with the possibility of net urea secretion at some point in the A. tigrinum nephron, followed by passive reabsorption in the distal segments under the influence of antidiuretic hormone. Key words: DNP, hypophysectomy, nephrostome, PAH, phloridzin, urea secretion. |
| Databáze: | OpenAIRE |
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