Epidermis extracts (chalone) inhibit cell flux at the the G1-S, S-G2 and G2-M transitions in mouse epidermis.
Epidermal cell flux at the G1-S, S-G2 and G2-M transition was examined during the first 4 hr after injection of epidermis extract. The flux parameters were estimated by a combination of several methods. The G1-S and S-G2 transit rates were calculated on the basis of a double labelling technique with [3H]TdR, the G2-M flux by means of colcemid and the relative proportion of cells in the S or G2 phase by means of flow cytometry. All experiments were performed both in early morning and late evening, corresponding to maximum and minimum rates of epidermal cell proliferation in the hairless mouse. The epidermis extract inhibited the S-G2 and G2-M transit rates to the same degree, while the inhibition of cell flux at the G1-S transit was consistently stronger. In general, the inhibition of cell flux at the different transitions was most pronounced when the rate of cell proliferation was low and vice versa.
D000818:Animals; D002453:Cell Cycle / Q000187:drug effects*; D002940:Circadian Rhythm; D000078404:Epidermal Cells; D006131:Growth Inhibitors / Q000494:pharmacology*; D007399:Interphase / Q000187:drug effects; D051379:Mice; D008938:Mitosis / Q000187:drug effects; D013997:Time Factors
D006131:Growth Inhibitors