Susceptibility of Fetal Lung to Transplacental 1-Ethyl-1-nitrosourea: Its Relation to Epithelial Proliferation 2

摘要: The relationship between the age-dependence of number lung adenomas produced by exposure fetal mouse to 1-ethyl-1-nitrosourea (ENU) and changes in epithelial cells within population that are cell cycle on different gestation days was studied. lining peripheral tubules growing were counted morphometric methods, and, based previous studies, their distribution various phases estimated. curve multiplicity biphasic, with maximum fetuses exposed 16 17 minimum those day 19. proliferative followed a similar pattern. A linear regression relating weeks after ENU showed correlation coefficient 0.82. more highly correlated G1 phase at carcinogen than either S or G2 mitosis. incidence per 10(6) greater when 15, tumors induced this grew significantly larger size birth did 17, 18, Factors possible significance age-related response may have been high growth fraction epithelium short cell-cycle time, longer period available for proliferation tumor initiation birth.