Open AccessEVIDENCE OF RAPID AND SLOW PROGRESSION OF CELLS THROUGH G 2 PHASE IN MOUSE EPIDERMIS: A COMPARISON BETWEEN PHASE DURATIONS MEASURED BY DIFFERENT METHODS
Author(s) -
Clausen O. P. F.,
Thorud E.,
Aarnæs E.
Publication year - 1981
Publication title -
cell proliferation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.647
H-Index - 74
eISSN - 1365-2184
pISSN - 0960-7722
DOI - 10.1111/j.1365-2184.1981.tb00528.x
Subject(s) - hairless , epidermis (zoology) , mitosis , population , biology , circadian rhythm , cell , microbiology and biotechnology , andrology , biophysics , endocrinology , anatomy , biochemistry , medicine , environmental health
Percentage labelled mitosis (PLM) measurements were initiated at four different times during a 24‐hr period and continued for 24 hr in hairless mouse epidermis. Estimates of G 2 and S phase durations (mean T G2 and mean T S ) were calculated. A significant number of labelled mitoses (10–20%) was seen after 30 min in all four PLM measurements and the estimated mean T G2 varied from 1.4 to 2.5 hr and was in agreement with values from PLM measurements in other epithelial tissues. These mean T G2 values were much shorter than expected from [ 3 H]TdR double labelling experiments and from a multiparameter cell kinetic study in hairless mouse epidermis and did not reflect the circadian variations seen in these studies. the differences in estimates of phase durations can be explained by postulating two G 2 cell populations; one with a rapid and another with a slow rate of cell cycle progression. the cells with the higher rate are mainly registered by the PLM method, whereas those with the lower rate largely escape detection by this method. T G2 estimates from PLM measurements in mouse epidermis therefore do not reflect the phase duration of the entire G 2 population. It is also concluded that circadian variations in T S can not be accurately registered by the PLM method.