イヌ膀胱のN-butyl-N-(4-hydroxybutyl)nitrosamine (BBN)による発癌過程とその尿中代謝物に関する基礎的研究

Abstract

BBNを投与したピーグル犬の尿中代謝ニトロソ化合物をgas-chromatographyおよび新しく開発されたthermal energy analyzer (GC-TEA)を用いて定性分析し, さらにgas-chromatography/mass-spectrometryにより同定し, 以下のような結果を得た.1) BBN投与犬の尿中よりN-butyl-N-(3-carboxypropyl)nitrosamine (BCPN), N-butyl-N-(2-hydroxy-3-carboxypropyl)nitrosamine (BHCPN), N-butyl-N-(carboxymethyl)-nitrosamine (BCMN), N-butyl-N-(2-oxopropyl)-nitrosamine (BOPN)およびBBN-Gの各代謝物を確認した.2)それら尿中ニトロソ化合物を再びGC-TEAを用いて定量分析したところ, 初期投与期間ではBCMNがもっとも多く, 次いでBHCPN, BCPNの順で, BOPNとBBNおよびBBN-Gは少量であった.後期投与期間ではBCMNとBCPNの増加とBHCPNの減少が認められた.3)膀胱粘膜の腫瘍発生時期の差はBCPNの尿中排泄量の差によるものと考えられた.4) BBNのグルクロン酸抱合体と腫瘍発生時期と間には特定の関係は得られなかった

N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) was administered to beagle dogs to examine the urinary metabolites. After extraction and purification of the urine sample, the urinary metabolites were identified by gas-chromatography mass-spectrometry and measured using a gas chromatograph equipped with a thermal energy analyzer (GC-TEA). Five N-nitroso-compounds (N-butyl-N-(3-carboxypropyl)nitrosamine (BCPN), N-butyl-N-(2-hydroxy-3-carboxypropyl)-nitrosamine (BHCPN), N-butyl-N-(carboxymethyl)-nitrosamine (BCMN), N-butyl-N-(2-oxopropyl) nitrosamine (BOPN) and BBN-glucuronide) were detected and identified by comparison with mass spectra of synthetic specimens. In the quantitative analysis by GC-TEA, BCMN greater than BHCPN greater than BCPN were larger part than BOPN and BBN-glucuronide. In early experimental period (0-25 wks) administered BBN (600 mg/day) to two dogs, small tumor was recognized in the urinary bladder of one dog earlier than the other. The former dog excreted larger amounts of BCPN in the urine than the latter. In late experimental period (100 wks approximately) administered BBN (400 mg/day) to five dogs, the dog that was found initial tumor earliest (103 wk) excreted the largest amounts of BCPN in the urine. Therefore, the excretion of BCPN had correlated with the carcinogenesis.