title: [Influence of roentgen rays on electrolyte changes and metabolism of the myocardium. VII. Radiation-induced inhibition of the sodium- and potassium--activated microscomal-trasport ATPase].
abstract: The behavior of a Mg2+-dependent microsomal ATPase, which may be activated by Na+ and K+, was investigated in the myocardium of Guinea pigs after local irradiation. The part which can be activated by Na+ and K+ (transport-ATPase) is already slightly inhibited thirty minutes after a dose of 250 R; the inhibition rate with 1500 R amounts to about 60%, the maximal inhibition effect with a dose of 3000 R was about 70%. Four hours after a local irradiation with 1500 R, a restitution of the inhibition effect occurs with overshoot reaction; 15 and 24 hours following irradiation, a significant inhibition of the transport-ATPase activity can again be verified. The k-strophanthidine and digitoxin are inhibiting within the concentration ranges analyzed (2 X 10(-5), 2.5 X 10(-7), 5 X 10(-7) M) the activity of the transport-ATPase. The above-mentioned radiation-induced inhibition effect upon the ATPase activated by Na+ and K+ is additively increased by adding k-strophanthidine (2 X 10(-5) M) and digitoxin (2.5 X 10(-7) M).
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000528:radiation effects; D004074:Digitoxin / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000528:radiation effects*; D008274:Magnesium / Q000378:metabolism; D008861:Microsomes / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D011188:Potassium / Q000378:metabolism; D011829:Radiation Dosage; D011830:Radiation Effects; D012964:Sodium / Q000378:metabolism; D013327:Strophanthidin / Q000494:pharmacology; D013997:Time Factors
chemical_list: D013327:Strophanthidin; D012964:Sodium; D004074:Digitoxin; D000251:Adenosine Triphosphatases; D008274:Magnesium; D011188:Potassium
vernacular_title: Untersuchungen über den Einfluss von Röntgenstrahlen auf Elektrolytverschiebungen und Stoffwechsel des Herzmuskels. VII. Strahlenbedingte Hemmung einer Na+- und K+-aktivierbaren mikrosomalen Transport-ATPase