Die Wirkung von Iproniazid sowie i.p. Zufuhr von Katecholaminen und ihrer O-Methylderivate auf die renale Ausscheidung von Metanephrin und Normetanephrin an der Ratte

The urinary excretion of epinephrine, norepinephrine metanephrine and normetanephrine was investigated in rats with and without pretreatment with iproniacide and i.p. administration of epinephrine, norepinephrine, metanephrine and normetanephrine. The following results could be obtained: In normal rats no detectable urinary excretion of metanephrine (MN) and normetanephrine (NMN) was found (below 15–20 µg/kg/24 hrs). In rats pretreated with iproniacide no MN but 46 µg/kg/24 hrs NMN was excreted in the urine. The i.p. administration of 400 µg/kg epinephrine or 800 µg/kg MN lead concordantly to an urinary output of MN with a yield of 11% of the given dose. Pretreatment with iproniacide increased the MN excretion following the administration of epinephrine and MN to 29% and beside caused a significant rise in the urinary NMN output. Following the i.p. administration of 400 µg/kg norepinephrine 7% and after the i.p. injection of 800 µg/kg NMN 13% were recovered as NMN in untreated animals and 11% and 19% in rats pretreated with iproniacide. There was a linear positive correlation between the amount of i.p. given MN and the urinary output of NMN within a dose range of 400–1600 µg/kg MN in rats pretreated with iproniacide, indicating a competitive displacement of NMN from specific tissue stores by MN. No such increased NMN urinary output could be detected following the i.p. administration of adrenalone and noradrealone.