Drinking behavior in thyroidectomized rats: effects of central cholinergic stimulation and of water deprivation

Normally hydrated thyroidectomized (TX) rats stimulated intracerebroventricularly with carbachol and dehydrated TX rats drank significantly smaller volumes of water than their respective controls. This suggests lower central sensitivity to thirst and to drinking behavior induced by both cholinergic activation and extracellular fluid depletion. Dehydrated TX rats excreted a significantly larger urinary volume than the controls, suggesting the existence of changes in the renal mechanisms of water retention. Such changes could be related to a reduction in vasopressin binding sites.