Clausen O P, Thorud E, Kauffman S L
Int J Chronobiol. 1982;8(2):83-93.
In histologic sections from hairless mouse epidermis, the total epidermal cell number and the numbers of basal and differentiating cells were determined per unit length, and cell density was calculated. Sampling was made every 2 h during 2 successive 24-h spans. All parameters showed circadian changes during both 24-h spans. The cell numbers per unit length and the cell density showed both high values around 12(00), some hours subsequent to the peak of mitotic activity. The loss rate of epidermal nucleated cells was calculated from first harmonic sine curves fitted to the circadian changes in total epidermal cell number and to the mitotic rate. The loss rate showed a circadian rhythm with increased values from after 16 00 to after 00(00). This implies that there is a circadian variation in the transition of differentiating cells into horny materials, and hence in cell differentiation.
在无毛小鼠表皮的组织学切片中，测定单位长度内的表皮细胞总数、基底细胞数和分化细胞数，并计算细胞密度。在连续两个24小时时间段内，每2小时进行一次取样。在这两个24小时时间段内，所有参数均呈现昼夜节律变化。单位长度的细胞数和细胞密度在12(00)左右显示出较高的值，这是在有丝分裂活动峰值后的几个小时。表皮有核细胞的丢失率是根据拟合表皮细胞总数昼夜节律变化和有丝分裂率的一次谐波正弦曲线计算得出的。丢失率呈现昼夜节律，从16:00之后到00(00)之后数值增加。这意味着分化细胞向角质物质的转变存在昼夜变化，因此细胞分化也存在昼夜变化。
