| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1990: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1989: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Recently, the endogenous digitalis like substance, which shows cross-reactivity with anti-digoxin antibody, is thought a possible cause of the essential hypertension, since this substance is reported to increase in the blood and urine of the patients of this disease. This substance enhances natriuresis, inhibits Na^+, K^+-ATPase and is considered to elevate blood pressure. Thus, using the inhibitory activity of rat brain Na^+, K^+ATPase as a marker, this substance was purified from urine of hypertensive rats which were removed of unilateral kidney, were injected wit deoxy-corti-costerone acetate and were given 1 % NaCl solution as drinking water. After collecting urine in the presence of HCL and boiling the ruine, the purification was done using CM-sepharose column chromatography, Sephadex G-10 column chromatography and reversed phase HPLC. Three substances which had inhibitory activity of the Na^+, K^+ATPase were purified. The inhibitory activities were dose-dependent, and the activit
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ies were not affected by the trypsin-digestion. however, these activities of the three substance were disappeared after the acid hydrolysis, and these of 2 substances out of the 3 were disappeared after the prolidase digestion. These substances also showed cross-reactivity to anti-digoxin antibody in dose-dependent manners and the cross-reactivity was parallel with the inhibitory activity of the Na^+, K^+-ATPase. One of the 3 substances also showed hypertensive action when it was injected into the lateral cerebral ventricle. These findings suggest that these substances are peptides or proteins. Amino acid analysis of these substances gave amino acids, but analysis using amino acid sequencer did not show any information about the sequences. Since it is impossible to determine amino acid sequence if the N-terminal of the peptide is blocked, we tried to remove the blockade. However, we could not to get the sequences. Therefore, we think contents of these substances in the urine were very low and we could not get enough substances to analyze the amino acid sequence. Thus, now we are trying to get enough substances to analyze the sequence. After succeeding to identify the sequences, we are going to examine the physiological roles of these substances. Less
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