from Colombia. This article summarizes our findings and reviews the pertinent literature in the field. Glomerular filtration rate and renal plasma flow. Reports of the investigation of renal function by modern clearance tests are so few that Smith [9] stated in his monograph 130 Klahr/Alleyne that: "Whether or not renal function is modified by prolonged undernutrition cannot be decided from available evidence." As far as tests of renal function are concerned, it may be appropriate first to review studies dealing with dietary protein restriction produced under controlled conditions. Pullman et al [10] described experiments in which they fed normal adults "high (2.3 to 3 g protein per kg body wt), medium and low (0.1 to 0.4 g protein per kg body wt)" protein diets. Glomerular filtration rate and renal plasma flow fell when subjects were fed the low protein diet and increased with the high protein diet. Filtration fraction did not change, but the transport maximum of PAH (TmPAH) increased with a high protein diet. Nielson and Bang [11], however, also studied noimal subjects fed varying amounts of protein and found that inulin and diodrast clearances were relatively unaffected by changes in the protein content of the diet. Sargent and Johnson [12] reported that when normal subjects were fed a calorie-deficient diet, irrespective of the percentage of calories from protein, fat or carbohydrate, there was a constant reduction in glomerular filtration rate as measured by the creatinine clearance. Table 1 summarizes data for glomerular filtration rate and renal plasma flow in children and adults with proteincalorie malnutrition. Alleyne [6] found that GFR was markedly reduced in malnourished children and increased as they recovered. He found no consistent difference in inulin or PAH clearances between edematous and nonedematous malnourished children. Arroyave et a! [13] found an average value for GFR of 14 mI/min/m2 in nine malnourished children, as compared to an average value of 45 mi/mm/rn2 in 17 well-nourished children. The wellnourished controls were older than the malnourished children, but the age difference alone could not explain the large difference in creatinine clearance values. Gordillo et a! [8] measured inulin and PAH clearances in ten children who were at least 40% below average weight for their age. Seven of these children were well hydrated and three were severely dehydrated. In the well-hydrated malnourished children the clearance rates were about half the normal values and in the dehydrated malnourished about one-fifth of normal. Klahr et al [14, 15] demonstrated a marked decrease in both GFR and CPAH in ten adults with protein malnutrition. Values for these measurements increased following protein repletion. GFR increased somewhat more during repletion leading to an increase in filtration fraction. Mollison [16] studied four subjects with malnutrition in the concentration camp of Belsen after World War II. He found normal clearances in two subjects with malnutrition but without edema, and reduced clearances in two other subjects with malnutrition and edema. In 11 adults with undernutrition, McCance [17] found an inulin clearance below 100 mI/mm in only one subject. The subjects reported by McCance presumably were not as severely malnourished as the individuals studied by Klahr et al [18] or Mollison [16]. On the other hand, Srikantia and Gopalan [19] studied five cases of severe malnutrition with "protein deficiency edema" and found no decrease in GFR or renal plasma flow. These subjects differ fromothers reported in the literature in that they were oliguric at the time of study. It is unexplained why these subjects had normal renal plasma flow in the presence of reduced blood volume and hypotension. It then seems that in children, protein-calorie malnutrition leads to a decrease in both renal plasma flow and glomerular filtration rate [6, 8]. In adult subjects, conflicting results on the effects of protein malnutrition on GFR and RPF have been reported [14, 17]. These differences in adults may relate to the severity and duration of the malnutrition. Possible mechanisms responsible for the decreased GFRand RPF. The forces determining glomerular filtration rate Table 1. Glomerular filtration rate and renal plasma flow in malnourished subjects Investigator No. of subjects Malnouri C1, shed CPAH mi/mm FF Replete No. of subjects d or Nor C1 mal CPAH mi/mm FF Alleyne [6] 8 children 7 childrena 47.1 42.9 249.4 184.0 0.21 0.27 14 children 92.4 321.2 0.29 Arroyave et al [13] 9 children 13.7 — — 9 children 17 normal children 33.9 45.0 — — Gordillo et al [8] 10 children 23.0 108.4 25 normal children 64.0 294 0.23 Klahr [14,15] 10 adults 64.1 325.8 0.20 10 adults 88.3 381.1 0.24 McCance [17] 11 adults 11 adults 119.4 100.9 — — — — Mollison [16] 2 adultsa 2adults 53, 70 124,141 230, 383 340,710b — a Edema was present in these subjects at the time of study. Mean values are given in mI/mm. The data for adults are corrected for 1.73 m2. The data of Arroyave and Gordillo are expressed per m2. The data of Alleyne are corrected for height (m3). b Diodone clearances. Chronic protein-calorie malnutrition 131 (GFR) have been well defined theoretically, but the actual regulation of filtration is not completely understood. GFR can be considered to be determined by these variables: GFR [KFA] [(pc it)— "TJ, where ElF