In the present study, the effects of diuretics on the sodium transport of the toad bladder were discussed on the membrane level. Using the urinary bladder of the toad, Bufo bufo japonicus, the short-circuit current (SCC) and the O2 uptake were measured. SCC was measured by the method of Ussing and Zerahn (1951), and O2 uptake was measured by oxygen electrode (Yanagimoto Co. Ltd.). As diuretics, chlormerodrin, hydrochlorothiazide, furosemide, and ethacrynic acid were used. Ouabain, which inhibits Na, K-dependent ATPase activity, was used as a control. The inhibitory effect of diuretics on the action of vasopressin, 3', 5'-cyclic AMP and amphotericin B, all three of which increase the sodium transport of the toad bladder, were measured. From these experments, the following results were obtained : Chlormerodrin, hydrochrorothiazide and furosemide seem to inhibit the ion permeability of the mucosal membrane of the toad bladder, or inhibit the activities of enzymes other than Na, K-dependent ATPase. The mode of action of ethacrynic acid seems to be different from that of ouabain. Our data suggest that ethacrynic acid inhibits either ATP production or adenyl cyclase activity.

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The peritoneum of rabbit was isolated from anterior and posterior walls, colon and omentum andd permeability of the peritoneum for ²⁴NaCl, ⁴²KC1, ¹⁴C-Urea and ¹⁴C-Glucose was investigated in vitro, getting following results ; 1) No difference of permeability was identified between serosal side and mucosal side. 2) The permebility coefficient was 10^-5 to 10^-6cm sec^-1 which was almost the same as that of cellophane membrane used in artificial kidney. This coefficient showed a tendency to decrease with the increase of molecular weight. 3) The permeability was the highest in omentum among four parts of peritoneum and the lowest in that of colon. Those of anterior and posterior abdominal walls were almost identical, which were they middle of the former two. Passive transport in peritoneum can be assumed since there was no significant difference of permeability between serosal side and mucosal side. The peritoneum may be a porous membrane for it showed the same permeability as cellophane membrane. The filtration coefficient calculated by Pappenheim suggests that the peritoneum supervenes other biological membranes in permeability except the capillary wall of glomerulus. ²⁴NaCl and ¹³¹I-Albumin was given to dogs intravenously in order to investigate disappearing curve in the blood and into the peritoneal cavity to investigate appearing curve in the blood. Permeability of the peritoneum in vivo was thus studied. 1) Absorption of ²⁴NaCl and ¹³¹I-Albumin from the peritoneal cavity was slower than the movement in capillaries. 2) When vena cava inferior was ligated to make stenosis, absorption of ²⁴NaCl from peritoneal cavity decreased remarkably. The hemodynamics of peritoneal capillary seems to have influence upon absorption of sodium from the peritoneal cavity. 3) On the contrary, absorption of alubumin increased. Increase of lymphatic flow of thoratic duct was noticed, suggesting its influence on absorption of alubumin. ¹⁴C-Urea was given to rabbit and man to investigate the distribution of urea. 1) Compartment analysis showed that urea exists in two compartments, extracellular and intracellular fluid, both under normal and uremic conditions. 2) By the calculated rate constants, a simulation of the peritoneal dialysis was modeled. We found the existence of urea disequilibrium in peritoneal dialysis by the Calculation of simulation model. 3) Specific activity of ¹⁴C-Urea of various tissues was investigated under uremic condition, and it took more time to attain equilibrium. Exchange of urea between extracellular and intracellular fluid is thus slow under uremic condition. 4) The difference of amount disappeared from blood and that excreted into urine was considered to be due to urea hydrolysis in the gut by bacterial urease. Under normal condition almost the same amount as that excreted into urine is hydrolysed in the gut. Under uremic condition, it is much more acceralated than normal.

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The glomerular lesions, induced by large doses of glucocorticoid administration, which are similar to exudative lesion of the diabetic nephropathy, are investigated by various experiments. The results are as follows : (1) When glucocorticoid was administered to rabbits, exudative lesions were observed in the glome-ruli, and the histochemical reactions shown in these glomeruli were similar to those of exudative lesions seen in human diabetic nephropathy. (2) When glucocorticoid was given together with aminonucleoside to rats, the exudative lesions made in these rats were more prominent than those in rats with glucocorticoid or aminonucleoside alone. (3) It appears that these exudative lesions induced by glucocorticoid have no relations with the existence of glycosuria or hyperglycemia. (4) Accordingly, it is considered that exudative lesion induced by glucocorticoid is not attributed to diabetes, but to glucocorticoid. (5) Although the developmental mechanisms of the exudative lesions are not yet fully known, it seems that hyperlipemia and related blood changes induced by glucocorticoid might be concerned. (6) The auther would like to propose to designate these exudative and other related lesions induced by glucocorticoid as "steroidnephropathy ".

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Hypoproteinemia is one of the prominent features in the nephrotic syndrme. In order to elucidate its pathogenesis, protein metabolism was investigated on the patients with nephrotic syndrome and on the animals made nephrotic with aminonucleoside or antikidney serum. The fractions of serum and urinary protein were investigated in 55 cases of nephrotic syndrme. There was a marked decrease of serum protein, especially of albumin, and the urinary protein consisted mainly of albumin. No definite correlation was obtained between the serum and daily urinary excretion of protein. Serum albumin, however, decreased in proportion to its excretion in the urine. The hypoalbuminemia is, however, often severer compared with the excreted amount of albumin in the urine. This fact suggests that some factors, other than urinary loss, might contribute to the hypoalbuminemia. Among these factors, decreased protein synthesis and increased catabolism are incl-uded. Since there is no evidence of lowered protein synthesis in the nephrotic syndrome, the increase in the albumin catabolism should be investigted. From this consideration, tracer experiment with 125I-labeled rat albumin were performed by 3-com-partmental analysis, using Wistar male rats weighing 100 mg. By this experiment, besides the increase in the urinary protein excretion, the decrease in albumin pool, the increase in the protein catabolism and the increase in permeabillity of blood vessels to protein which is shown by the increase of rute constant between each compartment, were revealed. Next, the protein catabolism was investigated on the kidney, liver and intestine. Even in the kidney of normal rats, protein is catabolized. In vivo experiment, this catabolism showed no differece between the normal and nephrotic rats kid-neys, but in vitro experiment, protein catabolism in nephrotic rats kidneye was significantly increased compared with the normal. In the nephrotic liver, protein catabolism was not prominent compared with the normal. Therefore protein synthesis seems to be a more important role in the liver of nephrotics. The protein leakage into the intestinal lumen was increased significantly in the nephrotics compared with the normal. From these data, it is concluded as follows. In nephrotic syndrome, the permeability of blood vessels to protein and turn over rate of albumin is increased. The increase of the protein catabolism in the kidney and the protein leakage through the intestinal mucosa may contribute, besides urinary loss, to the hypoalbuminemia in the nephrotics.

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In order to investigate the relationships between nephrotic hyperlipoproteinemia and its fatty acid compositions, various lipoproteins were separated ultracentrifugally in both normal and nephrotic subjects. Then these lipoprotein lipids were factionated by the method of thin layer chromatography and fatty acid compositions of lipoprotein lipids were determined by the techhique of gaschromatography. In addition, transportation of ingested linoleic acid was studied in both subjects. Results obtained were as follows 1) On the fatty acid composition in three lipoprotein classes, increase of palmitic acid % and decrease of linoleic acid % were observed in nephrotics as compared with normals. This tendency was almostt consistent through the three lipoprotein classes. 2) On the fatty acid compositions of same kind of lipids in three lipoprotein classes, increase of palmitic acid % and decrease linoleic acid % were consistently observed in nephrotic subjects. In cholesterol-ester fraction and especially phospholipid fraction of Sf 20-10⁵ class, the almost same results mentioned above were observed. Although patterns of fatty acid compositions in albumin bound free fatty acids fraction were quite consistent with that of triglyceride fraction in both, respectively, but increase of palmitic and decrease of oleic and linoleic acid % were observed in nephrotics. 3) Effect of oral administration of ethyl-linoleate Increase of ingested acid was observed in triglyceride fraction in both subjects. However, in nephrotics, the degree of linoleic acid % increment in triglyceride fraction of very low density lipoprotein was slight than that of normals and changes in phospholipid fraction of very low density lipoprotein and high density lipoprotein in nephrotics exceeded normals.4) Some discussions were made from the above mentioned results.

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