. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 210 J. WENDELL BURGER ster and Zia-Wohlrath (1941) of a glucose U/P ratio of one in Homarus is due undoubtedly to the high level of glucose employed. Phlorizin resulted in glycosuria with or without priming by sub-liminal exoge- nous glucose (10 lobsters). In short, under normal conditions there seems to be an active mechanism which excludes glucose from the urine, a mechanism which can be poisoned by phlorizin. 4. Phenol red. Phenol red was extracted from the blood by acid alcohol, read colorimetrically at 440 in//,, alkali
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 210 J. WENDELL BURGER ster and Zia-Wohlrath (1941) of a glucose U/P ratio of one in Homarus is due undoubtedly to the high level of glucose employed. Phlorizin resulted in glycosuria with or without priming by sub-liminal exoge- nous glucose (10 lobsters). In short, under normal conditions there seems to be an active mechanism which excludes glucose from the urine, a mechanism which can be poisoned by phlorizin. 4. Phenol red. Phenol red was extracted from the blood by acid alcohol, read colorimetrically at 440 in//,, alkalized and read again at 550 m/t. Urine and stomach fluid were treated similarly. It was found desirable to use control blanks from in- ro O ro. 0 24 48 HOURS 72 FIGURE 2. Urinary concentrations (U) of phenol red after injection into the hemocoele, over wider blood levels (P) than shown in Figure 1. Note the concentration of the dye in the digestive fluid (S). The isolated point is a urine value. dividual lobsters, and not to rely on a generalized control zero. Over thirty animals were studied. The pattern of nephridial excretion of phenol red is seen in Figures 1 and 2. At low plasma concentrations (Figs. 1, 2), the dye is clearly concentrated by the nephridium (the U/P ratio is a valid criterion; see paragraph on inulin). As the plasma level is raised, the U/P ratio approaches one (cf. Fig. 4). This is the pat- tern for all substances "secreted" by the nephridium; concentration is evident at low plasma concentrations but is apparently swamped by high plasma concentrations. It is to be remembered that the lobster's kidney is the elaboration of only one pair of nephrons. Phenol red is not lost or absorbed through the gills or body covering. Four lobsters were injected with 5-10 mg. and were placed for 18 hours in volumes of. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearan
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
