Autoradiographische Untersuchungen zur Toxikokinetik von Myosmin in Ratten
type: CreativeWork
description: Autoradiographic studies on myosmine toxicokinetics in rats Myosmine, a minor tobacco alkaloid was recently detected in a wide variety of nutritional plants including cereals, nuts, cocoa and dairy products. Under acidic conditions myosmine is easily nitrosated leading to pyridyloxobutylation either directly or through the formation of N'-nitrosonornicotine (NNN). In NNN-treated rats DNA adducts releasing 4-hydroxy-(3-pyridyl)-1-butanone (HPB) are made responsible for tumours in oesophagus, oral and nasal cavities. Whereas the pharmacokinetics and metabolism of NNN have been studied in detail no such data have been available for myosmine. In the present study time-dependent distribution, binding and excretion of radiolabelled myosmine was investigated in pigmented and albino rats by quantitative whole-body autoradiography. One rat each was sacrificed by CO2 asphyxiation six and 15 minutes as well as 1, 4 and 24 hours after intravenous injection Zusammenfassung / Summary 91 of myosmine (5-3H: 1.4 µg/kg; 8.49 MBq/kg or 2’-14C: 0.27 mg/kg; 3.74 MBq/kg). Sagittal sections of 40 µm thickness obtained after deep freezing of the rats, were exposed to image plates either before or after serial extraction with solvents and water. Additionally, sections of eyes and oesophagus of untreated rats were incubated in vitro with 2’-14C myosmine. The rats killed four and 24 hours after myosmine injection were separately housed in metabolism cages for collection of urine and faeces. High concentrations of radioactivity were present six minutes after myosmine application in Harder's gland, lacrimal, salivary and accessory genital glands, nasal cavity, liver, kidney cortex, wall of the stomach fundus as well as the melanin rich parts of the eye and skin. An accumulation of radioactivity was also seen in the contents of the stomach and bladder. A similar distribution pattern was evident after 15 minutes and one hour with stronger accu-mulation in oesophagus, medulla of kidneys and access…
abstract: Autoradiographic studies on myosmine toxicokinetics in rats Myosmine, a minor tobacco alkaloid was recently detected in a wide variety of nutritional plants including cereals, nuts, cocoa and dairy products. Under acidic conditions myosmine is easily nitrosated leading to pyridyloxobutylation either directly or through the formation of N'-nitrosonornicotine (NNN). In NNN-treated rats DNA adducts releasing 4-hydroxy-(3-pyridyl)-1-butanone (HPB) are made responsible for tumours in oesophagus, oral and nasal cavities. Whereas the pharmacokinetics and metabolism of NNN have been studied in detail no such data have been available for myosmine. In the present study time-dependent distribution, binding and excretion of radiolabelled myosmine was investigated in pigmented and albino rats by quantitative whole-body autoradiography. One rat each was sacrificed by CO2 asphyxiation six and 15 minutes as well as 1, 4 and 24 hours after intravenous injection Zusammenfassung / Summary 91 of myosmine (5-3H: 1.4 µg/kg; 8.49 MBq/kg or 2’-14C: 0.27 mg/kg; 3.74 MBq/kg). Sagittal sections of 40 µm thickness obtained after deep freezing of the rats, were exposed to image plates either before or after serial extraction with solvents and water. Additionally, sections of eyes and oesophagus of untreated rats were incubated in vitro with 2’-14C myosmine. The rats killed four and 24 hours after myosmine injection were separately housed in metabolism cages for collection of urine and faeces. High concentrations of radioactivity were present six minutes after myosmine application in Harder's gland, lacrimal, salivary and accessory genital glands, nasal cavity, liver, kidney cortex, wall of the stomach fundus as well as the melanin rich parts of the eye and skin. An accumulation of radioactivity was also seen in the contents of the stomach and bladder. A similar distribution pattern was evident after 15 minutes and one hour with stronger accu-mulation in oesophagus, medulla of kidneys and access…
author: Glas, Susanna
date published: 2003-02-07
date modified: 2026-07-24T02:51:38Z
provider: Ludwig Maxmilians Universität München
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Ludwig-Maximilians-Universität