A Single Experience with Hyperoncotic Colloid Dialysis Persistently Alters Water and Sodium Intake
Subcutaneous administration of high molecular weight colloids, such as polyethylene glycol (PEG), in hyperoncotic concentrations produces acute increases in water and saline intake, and is used extensively as a model system for hypovolemic thirst (1). Homeostasis in this state is defended both by renal conservation of water and sodium and by the ingestion of water and sodium. In the course of analyzing this effect, we noted that rats receiving an injection of PEG showed a persistently elevated preference for 0.3 M NaCl. Similar persistent increases of saline intake have been noted by other investigators (2,3,4). The experiments described here were designed to investigate several possible mechanisms underlying the prolonged increase in saline intake which followed a single experience with PEG.
KeywordsSodium Intake Dietary Sodium Restriction Sodium Appetite Daily Fluid Intake Purina Chow
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