Two groups of rats received amphotericin-B (Amp). One group (AA) received a single acute dose of 1 mg/kg i.v. The second (CA) received 10 mg/kg i.p. daily for 4 days. In AA rats, measurements 1 to 5 hr after Amp were compared with their own preinfusion values. Inulin clearance, (CIn, 4.5 ml X min-1 X kg-1 per kidney pre vs. 1.3 post), renal plasma flow (RPF, 12.0 ml X min-1 X kg-1 vs. 7.4), and the estimated pressure in the glomerular capillaries (Pgc, 52 mm Hg vs. 40), were all significantly decreased while renal vascular resistance (5.2 mm Hg/ml vs. 12.0) was increased. Only 45% of the 3H-inulin injected into surface tubules was recovered in the urine as contrasted with 100% recovery before injection. This suggests that tubule permeability was increased, but there was no histologic evidence of renal tubule necrosis. Twenty-four hours after intravenous Amp, CIn and RPF returned to normal. Data from CA rats were compared with values from sham-treated pairfed (PF) control rats. Again, CIn (4.22 ml X min-1 X kg-1 in PF vs. 2.69 in CA), RPF (16.1 ml X min-1 X kg-1 vs. 8.3), and Pgc (48 mm Hg vs. 38) were decreased, and renal vascular resistance (4.9 mm Hg/ml vs. 8.0) was increased. The recovery of 3H-inulin in the urine was slightly, but significantly, decreased (96% vs. 83%). These findings demonstrate that Amp decreases renal function by at least two mechanisms. An increase in renal vascular resistance is most important, although increased tubule permeability with a "backleak" of tubule fluid also contributes to renal dysfunction, particularly after intravenous Amp.

The relative bioavailability of zinc (RBAZ) in corn, rice, wheat and legumes was determined by the ratio of net weight gains a 6 ppm of added zinc, a measure derived from sigmoidal curves for weight gain estimated by a non-linear, least-squares curve fitting computer program. Each food was prepared as for human consumption, incorporated into a semi-purified diet to provide varying levels of zinc and fed to weanling rats. Among cereals, whole corn and brown rice had low RBAZ (0.58 or less), while whole wheat flour and unleavened whole wheat bread had medium values (0.63-0.74). Refined cereal grains, such as white flour, leavened and unleavened white bread and white rice, had high RBAZ (0.89-1.08) as did leavened whole wheat bread (1.04). Of the legumes, lima beans had a high RBAZ (0.84) while white beans had a medium value (0.74). Phytic acid content of the foods, but not neutral-detergent fiber content, appeared to be inversely related to RBAZ, more so among the cereals than with the legumes.

The bioavailability of iron formed by the corrosion of low-carbon steel (99% Fe) in contact with Red Delicious apples was measured in a rat model using a depletion-repletion experiment. The percentage of ingested iron converted to hemoglobin iron (Conversion Efflciency) was 74, 57, and 56%, respectively, for daily doses of 110, 190, and 285 pg of this iron. (Conversion Efficiency for FeS04 was 46-50%). When compared with FeS04 = 100, the relative biological value of this iron was found to range from 93-153. Ingestion of one Red Delicious apple that has been exposed to eight large iron nails for 24 hr could provide lo-15 mg iron having good bioavailability. every other day as frozed iron/apple supplements that had been allowed to thaw before presentation. In every case, these iron/apple supplements were consumed by the animals within an hour of presentation, which was always during morning, daylight hours. There was no loss of supplement due to dropping. Four groups were fed the basal diet having 0, 6, 12, or 24 ppm iron as ferrous sulfate which was added dry to the basal diet rather than incorporated into frozen apple supplements or another form of liquid supplement in order to insure that the chemical form of the iron presented to these animals was, in fact, ferrous sulfate. These four groups were fed adlibitum. After 12 days, hemoglobin values were again determined for each animal.