Beta-adrenergic control of the water permeability of the skin during rehydration in the toad Bufo arenarum.

1. Toads dehydrated to 80% of their standard weight (% SW) were rehydrated during 3 hr in distilled water. 2. Water permeability of the skin was positively correlated with the degree of dehydration in the range 80-100% SW. 3. Systemic administration of the beta-adrenergic agonist isoproterenol (5 mg/kg) 90 min after rehydration started (animals fully hydrated) increased skin permeability to the values observed in 80% SW dehydrated animals. 4. The administration of the beta-adrenergic blocker propranolol (5 mg/kg) 15 min before rehydration started produced a long-lasting decrease in water permeability during the 3 hr of rehydration. 5. The results are consistent with the hypothesis of a beta-adrenergic control of the water permeability of the skin during rehydration.