Effects of parathyroid hormone on H+ and NH 4 + excretion in toad urinary bladder |
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Authors: | Loy W. Frazier |
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Affiliation: | (1) Department of Physiology, Baylor College of Dentistry, 75226 Dallas, Texas |
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Abstract: | Summary The urinary bladder ofBufo marinus excretes H+ and NH4+, and the H+ excretion is increased after the animal is placed in metabolic acidosis. The present study was done to determine if parathyroid hormone could stimulate the bladder to increase the excretion of H+ and/or NH4+. Parathyroid hormone added to the serosal solution in a final concentration of 10 g/ml was found to increase H+ excretion by 50% above the control hemibladders, while there was no effect on NH4+ excretion. Parathyroid hormone had no effect on H+ excretion when added to the mucosal solution. We also performed experiments utilizing theophylline and dibutyryl cyclic AMP which mimicked those of the parathyroid hormone experiments. A dose-response analysis was performed and the results indicate that 1 g/ml of parathyroid hormone was the minimal effective dose. These results suggest that parathyroid hormone can stimulate H+ excretion in the toad urinary bladder and this effect seems to be mediated by cyclic AMP. In addition, it was found that parathyroid hormone has no effect on NH4+ excretion. |
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