Otani K, Yano Y, Hasuma T, Arakawa T, Kobayashi K, Matsui-Yuasa I, Otani S
Department of Biochemistry, Osaka City University Medical School, Japan.
Am J Physiol. 1998 Feb;274(2):G299-305. doi: 10.1152/ajpgi.1998.274.2.G299.
Oral administration of 1 ml of 3.42 M NaCl solution to rats induced spermidine/spermine N1-acetyltransferase (SSAT) activity in gastric mucosa as well as ornithine decarboxylase (ODC) activity. SSAT activity increased and peaked at 5 h and again at 7 h, whereas ODC activity peaked at 6 h. SSAT mRNA also increased after 3.42 M NaCl administration to an extent similar to the increase in SSAT activity at 5 h. Intracellular putrescine level and DNA synthesis were increased by NaCl administration. A polyamine oxidase inhibitor, N,N'-bis(2,3-butadienyl)-1,4-butanediamine (MDL-72527), but not an ODC inhibitor, alpha-difluoromethylornithine (DFMO), inhibited the increases in putrescine level and DNA synthesis at 5 h. The inhibition of DNA synthesis by MDL-72527 was reversed by putrescine administration. In contrast, both MDL-72527 and DFMO inhibited the increase in putrescine level and DNA synthesis at 16.5 h. These findings suggest that putrescine produced from preexistent spermidine by SSAT is responsible for the initial DNA synthesis after mucosal injury induced by NaCl and that both SSAT and ODC are involved in formation of putrescine, which is required for subsequent DNA synthesis.
给大鼠口服1 ml 3.42 M氯化钠溶液可诱导胃黏膜中的亚精胺/精胺N1 - 乙酰转移酶（SSAT）活性以及鸟氨酸脱羧酶（ODC）活性。SSAT活性增加，并在5小时时达到峰值，7小时时再次达到峰值，而ODC活性在6小时时达到峰值。给予3.42 M氯化钠后，SSAT mRNA也增加，其增加程度与5小时时SSAT活性的增加程度相似。给予氯化钠可增加细胞内腐胺水平和DNA合成。一种多胺氧化酶抑制剂N,N'-双(2,3 - 丁二烯基)-1,4 - 丁二胺（MDL - 72527），而非ODC抑制剂α-二氟甲基鸟氨酸（DFMO），可抑制5小时时腐胺水平和DNA合成的增加。给予腐胺可逆转MDL - 72527对DNA合成的抑制作用。相反，MDL - 72527和DFMO均可抑制16.5小时时腐胺水平和DNA合成的增加。这些发现表明，由SSAT将预先存在的亚精胺转化产生的腐胺是氯化钠诱导黏膜损伤后初始DNA合成的原因，并且SSAT和ODC均参与腐胺的形成，而腐胺是后续DNA合成所必需的。
