Epidermal proliferation characteristics are similar in the pilary canal of mouse hair follicles and in interfollicular epidermis
Proliferation characteristics of basal cells in the pilary canal of resting hair follicles were investigated and compared with corresponding parameters in interfollicular epidermis of hairless mice. The mitotic rates had similar 24-h means at both locations. Distinct circadian rhythms which showed phasing and amplitudes similar to that in interfollicular epidermis, were demonstrated by the3H-TdR labelling index, the mitotic rate and the mitotic index. Influx of cells to and efflux of cells from the S phase were measured in the early morning and in the evening by a3H-TdR double labelling method. The influx values were similar at both times of both locations. The efflux values recorded in the morning were more than twice the values seen in the evening in both the pilary canal and in interfollicular epidermis. The epidermal mitotic rate in the pilary canal was depressed by epidermal extracts, and increased after adhesive tape stripping in the same way as in interfollicular epidermis. The results indicate no heterogeneity in cell proliferation characteristics between the two locations, and suggest that similar mechanisms are responsible for maintainance of growth equilibrium at both sites.
Key wordsDNA synthesis Cell division Epidermis Hair follicles Hairless mice
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- Bullough WF, Laurence EB (1958) The mitotic activity of the follicle. In: Montagna W, Ellis RA (eds) The biology of hair growth. Academic Press, New York, pp 171–187Google Scholar
- Clausen OPF, Lindmo T, Sandnes K, Thorud E (1976) Separation of mouse epidermal basal and differentiating cells for microflow fluorometric measurements. Virchows Arch [Cell Pathol] 20:261–275Google Scholar
- Iversen OH, Evensen A (1962) Experimental skin carcinogenesis in mice. Acta Pathol Microbiol Scand (Suppl) 156:13Google Scholar
- Iversen OH, Bjerknes R, Devik F (1968) Kinetics of cell renewal, cell migration and cell loss in the hairless mouse dorsal epidermis. Cell Tissue Kinet 1:351–367Google Scholar
- Iversen U, Iversen OH (1967) Cycles of hair growth in hairless mice. Acta Pathol Microbiol Scand 69:50–62Google Scholar
- Moffat GH (1968) The kinetics of cell populations in the growing hair follicle of the mouse as revealed by autoradigraphy using H-TdR. In: Baccaredda-Boy A, Moretti G, Fry JR (eds) Biopathology of pattern alopecia. Karger, New York, pp 90–106Google Scholar
- Tvermyr EMF (1969) Circadian rhythms in epidermal mitotic activity. Diurnal variations of the mitotic index, the mitotic rate and the mitotic duration. Virchows Arch [Cell Pathol] 2:318–325Google Scholar
- Tvermyr EMF (1972) Circadian rhythms in hairless mouse epidermal DNA-synthesis as measured by double labelling with H3-thymidine (H3Tdr). Virchows Arch [Cell Pathol] 11:43–54Google Scholar