We determined the position, dimensions, and structure of the kidneys, ureters, bladder, and urethra of 62 female sheep by use of ultrasonography. A 5.0-MHz convex transducer was placed over the right flank to examine the kidneys, and a 5.0 MHz-linear transducer was used to examine the bladder and urethra transrectally. All examinations were performed on sheep in standing position. The left kidney was 7.1 to 8.9 cm long, 3.4 to 5.5 cm wide, and 3.3 to 4.7 cm deep. Diameter of the parenchyma and renal sinus of the left kidney ranged between 1.1 and 1.9 cm and 1.1 and 2.0 cm, respectively. Circumference of the medullary pyramids varied between 2.1 and 3.3 cm. Similar ultrasonographic measurements were obtained for the right kidney. The diameter of the bladder varied between 0.3 and 6.9 cm in 96.8% of the sheep. The diameter of the bladder could not be determined in 32% of the sheep because it was > 10 cm, and, therefore, was beyond the penetration depth of the scanner. The only part of the urethra that could be ultrasonographically visualized was the internal urethral orifice. It had diameter between 0.1 and 0.2 cm. The ureters could not be ultrasonographically visualized in any of the sheep examined. The urinary tract of 8 sheep was examined 10 times within 2 weeks to examine whether measurements were reproducible. The interassay variation coefficient determined ranged from 3.1 to 31.8%, although for most variables, it ranged between 5 and 11%. Measurements for the length and width of the kidneys had the smallest interassay variation coefficient, whereas values obtained for diameter of the bladder and urethra, as well as thickness of the bladder, had the largest. It was concluded that the ultrasonographic findings described in this study can be used as references for diagnosis of morphologic changes in the kidneys, bladder, and urethra of sheep.

Effects of a protein meal (2.7 g of casein/kg of body weight) on glomerular filtration rate (GFR) and renal plasma flow (RPF) were assessed in dogs after 15/16 nephrectomy (n = 10), and were compared with observations in dogs with intact kidneys (n = 5). Increase in GFR and RPF was observed in both groups of dogs between 1.5 and 8 hours after protein ingestion. A maximal value for GFR was observed between 4 and 5 hours after protein ingestion in dogs of both groups. Enhancement of urinary protein excretion was evident in partially nephrectomized dogs after protein ingestion (P < 0.05), a result that was confirmed by 24-hour total urine collection from partially nephrectomized dogs fed a balanced ration. A qualitatively similar vasodilatory response was observed in partially nephrectomized dogs and in dogs with intact kidneys, and the mean maximal increase of GFR and RPF expressed as a percentage of baseline values in the latter dogs (47.0 +/- 8.1 and 43.6 +/- 10.3%, respectively) exceeded that observed in partially nephrectomized dogs (20.8 +/- 2.2 and 22.7 +/- 6.3%, respectively; P < 0.01). The incremental response of the kidneys to protein ingestion was directly related to the degree of renal function, as reflected in the linear regression relationship between the incremental increase in GFR and the baseline value for GFR (P < 0.01, R2 = 0.721).

It has been established that L-gamma-glutamylated derivatives of alpha-amino acids are delivered more efficiently to the kidneys than are the parent alpha-amino acids. Therefore, we synthesized L-gamma-glutamyl-S-(1,2-dichlorovinyl)-L-cysteine (L-gamma-glutamyl-L-DCVC), the simplest L-gamma-glutamylated derivative of the nephrotoxic alpha-amino acid S-(1,2-dichlorovinyl)-L-cysteine (L-DCVC), and investigated its effects on renal function and ultrastructure in pentobarbital-anesthetized dogs. Intravenous doses of 23.15 and 92.60 micromoles of L-gamma-glutamyl-L-DCVC/kg of body weight induced significant increases in urinary protein output and significant decreases in the clearance of inulin during the 6-hour post-injection period. Changes were not observed in any of the other 13 renal function variables or in the 11 plasma and blood variables that were monitored throughout the same period. Both doses of L-gamma-glutamyl-L-DCVC induced renal ultrastructural lesions in the S1 and S2 cells of the canine proximal tubule; the remaining 8 cell types downstream and the glomeruli were not damaged. The onset and magnitude of renal function changes and the cell types affected by L-gamma-glutamyl-L-DCVC were virtually identical to those observed previously following IV administration of equivalent doses of L-DCVC to pentobarbital-anesthetized dogs. Rapid removal of the L-gamma-glutamyl group from L-gamma-glutamyl-L-DCVC (ie, deglutamylation) resulting in formation of the parent alpha-amino acid, L-DCVC, can best explain the extreme similarity in the nephrotoxic profiles of these 2 toxicants.