The transtubular electrical potential differences (TTPD) of the rat kidney were mesured by means of microelectrode technique under the normal and various conditions described as follows.
1. Mean of TTPD under the normal condition was -20.0±6.2 mV (8 animals, 116 observations) in the proximal tubule, and -38.5±7. 9 mV (7 animals, 101 observations) in the distal tubule.
2. Mean of TTPD upon cooling the kidney surface with cold Ringer's solution (O°C-4°C) was -15.5 ±4.4 mV (3 animals, 71 observations) in the proximal tubule, and -23.5±5.6 mV (3 animals, 54 ob-servations) in the distal tubule. Significant depression of TTPD was observed in both proximal and distal tubules under the cooling condition.
3. By infusion of 10 mM DNP into the tubule lumen by means of micropuncture technique, mean of TTPD was reduced to -10.9±4.1 mV (3 animals, 54 observations) in the proximal tubule, and to -27.4±7.4 mV (2 animals, 14 observations) in the distal tubule.
4. Mean of TTPD under the antidiuretic condition was -20. 5±6. 0 m V (4 animals, 126 observations) in the proximal tubule, and -40.6±12.2 mV (4 animals, 102 observations) in the distal tubule. By the infusion of pitressin into the tubule lumen by means of micropuncture technique, mean of TTPD was -19.1±5.1 mV (3 animals, 50 observations) in the proximal tubule and -36.2±7.1 mV (4 animals, 33 observations) in the distal tubule. No significant difference in TTPD was observed under the normal and antidiuretic conditions.
5. Under the condition of mannitol diuresis, mean of TTPD was -21.3±5.7 mV (4 animals, 129 observations) in the proximal tubule and -39.5±10.6 mV ( 5 animals, 51 observations) in the distal tubule.
6. When norepinephrine was intravenously injected and systemic blood pressure rised, mean of TTPD was -19.4±5.1 mV in the proximal tubule and -34.6±7.7 mV in the distal tubule. By the intra musculary injection of norepinephrine, mean of TTPD was -18.7±3.8 mV in the proximal tubule and 31.3±6.9 mV in the distal tubule. The latter change was statistically significant, although it was small.

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This study was performed in an attempt to elucidate the pharmacologic effects and chemical compositions of the urodepressor substance by means of Oshima and Takagi's method.
This substance was qualitatively confirmed to be as a protein compound by using the methods such as dyeing technic on the filter paper, agar gel electrophoresis and paper zone electrophoresis.
Bioassay of this substance was carried out with respect to the vasodepressor effect of the rat carotic artery and contractioe effect of the isolated guinea-pig ileum.
The difference in depressor activity, which was analyzed by paper chromatography and amino acid analyzer, of the urine from healthy persons and hypertensive patients was observed.
The results are shown as follows.
(1) The urodepressor substance is a kind of plasma kinin like substance, having the depressor effect of arterial blood pressure and a gradural contraction of the guinea-pig ileum.
(2) This substance is considered to be rather small molecule of protein or peptides, consisting of 10 or much more amino acids.
(3) Vasodepressor activity of urine of healthy persons is more potent than hypertensive patients.
The constituent amino acids of both urine from healthy and hypertensive subjects were not different qualitatively, but, in hypertensive samples, quantitatively an increase in lysine, glutamic acid, alanine and leucine was found.
From these results, it may be concluded that the activity is dependent on the chemical structure of protein or peptide chains or en zyme activities for its activation.

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In order to obtain information on the real state of hyper-lipoproteinemia in nephrotic syndrome in Japanese subjects, Serum lipoproteins were ultracentrifugally determined in 19 cases of the patients with nephrotic syndrome and 38 cases of matched controls.
Results obtained are as follows:
1) In the nephrotic patients, low density Sf 0-12, 12-400 lipoprotein levels were significantly elevated although high density lipoprotein levels were decreased.
2) Hyperlipoproteinemia of nephrotic patients may be subdivided into 2 groups from the aspect of low density lipoprotein spectrum.
3) Significant inverse relationship existed between Sf 0-12 lipoprotein levels and serum albumin levels. Much less inverse relationship existed between Sf 12-400 lipoprotein levels and serum albumin levels.
4) Changes of lipids composition of various lipoprotein fractions in nephrotic patients were not so significant.
5) Several number of discussions were performed from obtained data.

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