The Control of Renal Blood Flow and Glomerular Filtration in Normal Man

Abstract

This report is concerned with the effective renal blood flow and rate of glomerular filtration in normal man, as determined by the diodrast and inulin clearances (26) during diuresis and during the action of phlorizin, adrenin, caffeine, nitrite, and typhoid vaccine. The observations not only throw light on the action of these agents, but also afford information concerning the physiological control of renal blood flow and glomerular activity.Typical data are reported graphically. On the assumption that the diodrast plasma clearance (indicated by D in the figures) is a complete clearance, this value is taken as equal to the effective renal plasma flow, i.e., the flow of plasma to active excretory tissue. To convert this figure to the effective whole blood flow it is only necessary to divide it by the per cent of plasma in the blood. For brevity, the term " effective " will be omitted from the discussion without, however, neglecting the physiological distinction between the diodrast clearance and the actual plasma flow which must be somewhat larger than the former in consequence of the inclusion of inert tissue. The filtration rate has been measured by the inulin clearance (IN). The filtration fraction (FF) (i.e., the apparent fraction of the plasma cleared through the glomeruli) is given directly by the inulin/diodrast clearance ratio. The Inulin, diodrast, and phenol red were given by constant intravenous infusion. The priming infusion consisted of 12 grams of inulin, 1.5 cc. of 10 per cent phenol red, and 1.5 cc. of 35 per cent diodrast solution in 100 cc. of 0.85 per cent saline, given at the rate of 10 cc. per minute. The sustaining infusion consisted of 45 grams of inulin, 10 cc. of phenol red, and 12 cc. of diodrast in 1000 cc. of saline, given at the rate of 4 cc. per minute. All details of technique were the same as those reported in the general description of methods given elsewhere (26). Figure 1 (Subject B. L., 1.83 sq. m., 52 per cent plasma) presents observations on the plasma flow and filtration rate during water diuresis in man. After three control periods, water was administered in four 250 cc. portions at five-minute intervals in order to minimize any disturbance of the systemic circulation. The urine flow, shown graphically, rose from 1.8 cc. to 14.2 cc. per minute. There was no change in the rate of glomerular filtration. The plasma flow decreased slightly, but there is no reason to believe that this circumstance was a result of the administration of water, or that it was causally related to the induction of diuresis. These observations are consonant with the evidence, which has been fully re-683 Water diuresis

The Effects of Spinal Anesthesia on the Circulation in Normal, Unoperated Man With Reference to the Autonomy of the Arterioles, and Especially Those of the Renal Circulation

“…The phenol red clearance serves as a check on the diodrast clearance, the constancy of the phenol red/diodrast clearance ratio before and after anesthesia demonstrating that procaine per se has no effect upon the tubular excretory mechanism. The infusions corresponded to the typical infusion cited by Chasis, Ranges, Goldring, and Smith (18). Zero time was taken as the beginning of the priming infusion, which occupied about 10 minutes; the infusion was then changed to the sustaining infusion, the first urine collection period being started at about 30 minutes.…”

Effective Renal Blood Flow in Subjects With Essential Hypertension 12

“…3. Locus of increased renal resistance The question whether the increased renal resistance deduced above involves obstruction on the afferent or efferent side of the glomerular bed can be examined by reference to the filtration In normal subjects the filtration rate tends to remain constant when the renal blood flow is increased during pyrogenic hyperemia or decreased by adrenalin, a circumstance which indicates that the locus of changing resistance is at the efferent glomerular arteriole (3,14 hyperemia. (The data on experimentally induced hyperemia will be discussed in the next section.…”

Methods for the assessment of the effects of drugs on renal blood flow.

“…The first attempts to measure renal plasma flow used hippuran and phenol red (Chassis, Ranges, Goldring & Smith, 1938). The extraction efficiency of these compounds was between 80 and 95% so that here RPF=C/0.85 when E=85%.…”