Mild and severe degrees of hydration were produced in anesthetized dogs by constant infusion of dextrose in water at different rates. When water diuresis ensued, and after adequate control periods, vasopressin was infused for 2 1/2 hr. The magnitudes of urine flow and Na excretion varied directly and osmolal urine-to-plasma ratio varied inversely with the degree of hydration. During mild hydration, glomerular filtration rate and osmolal clearance remained practically unchanged, whereas during severe hydration they increased. In another group of animals, similarly prepared, kidneys were removed at appropriate times and tissue was obtained from various areas for Na analysis. During uninterrupted water diuresis the medullary gradient for Na was practically dissipated. Vasopressin promoted the repletion of medullary Na during mild hydration, but only slightly ameliorated the disturbance during severe hydration. These data demonstrate that during vasopressin infusion the renal concentrating response and Na excretion were significantly modified by the degree of hydration, and evidence is presented for several possible causes.

The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

Common carotid arteries were occluded bilaterally for 5 min below the thyrocarotid arterial junctions in mildly hydrated, anesthetized dogs. Within 5–15 min after the occlusion, urine flow declined and remained below control values for 30–105 min. Concurrently, the urine became hypertonic to systemic plasma and there was no evidence for renal vasoconstriction or increased solute reabsorption. The decrement in urine flow was accounted for entirely by the decline in free-water clearance. Prolonged periods of occlusion or increased hydration altered the response. Bilateral occlusion of the common carotid arteries for 5 min above intact thyrocarotid arterial junctions (but below the carotid sinuses) or below denervated thyrocarotid arterial junctions did not affect urine flow. The time course of the response, the characteristics of the urine, and the absence of renal vasoconstriction suggest that the procedure induced a reflex release of antidiuretic hormone. Furthermore, the data indicate that the receptor area for this reflex is located in the region of the junction of the common carotid and thyroid arteries.

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1. Indwelling non-occlusive catheters were placed in the vena porta and inferior vena cava of female rats several days before experimentation. Isotonic saline or isosmotic glucose (2% of body wt.) was infused into one vein followed one to several days later with an identical infusion into the other vein of each conscious animal. 2. Significantly higher urine flow and sodium excretion resulted from infusion of isotonic saline (0.5 ml/min) into the vena porta than into the vena cava. Modest prehydration or section of the hepatic branch of the right vagus did not affect the differential sodium response. Changes in endogenous creatinine clearance and potassium excretion were not significantly different for the two routes. Mean values for net peak sodium excretion and contemporaneous urine flow, urinary sodium concentration, and fractional sodium excretion were significantly higher for the portal than for the caval infusion while differences in glomerular filtration rate and filtered sodium load were insignificant. No significant difference in sodium excretion resulted from infusion of isosmotic glucose by the two routes. 3. Compared to the response promoted by the isotonic saline load infused at 0.5 ml/min, the differential response in sodium excretion was prolonged when the same load was infused at 0.375 ml/min. Sodium excretion was not significantly different for the two routes when the same isotonic saline load was infused at 0.75 ml/min. 4. These experiments provide evidence for participation of the liver in the control of sodium excretion and suggest release of a hepatic humoral factor which may be controlled by the duration of exposure of the hepatic circulation to an adequate load of isotonic saline.

The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

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