PERIODICITY IN HUMAN BEINGS AND MICE 



847 



^ 50 



< 



o 



-40 

 Ql 



o 30 



CL 

 If) 



o 



c 



Cl 



20 



< 



CO 



Light 06.00 to 18.00 



Light I8:00 toOe.OO 



D 

 ■ 



08:30 

 20:30 





Fig. 21. Shift in phase of microsomal phospholipid rhythm in mouse 

 liver after inversion of lighting regimen. 



et al., 1957; Jardetzky et al, 1956). Mitotic activity in pinnal epi- 

 dermis and hepatic parenchyma (Fig. 22) and hepatic RNA and 

 DNA metabolism (Fig. 23) were studied at two time points, with 

 mice on a reversed schedule for 8 days (hepatic mitoses), 2 weeks 

 (RNA and DNA), and 23 days (pinnal mitoses), respectively. The 

 two series on serum corticosterone (Fig. 24) each describe seven 

 groups of mice killed at 4-hr intervals throughout a 24-hr period; in 



LIVER PARENCHYMA 



PINNAL EPIDERMIS 



10.0 



8.0- 



6.0' 



- 4.01/1 



2-0 



08 00 



24:00 08^00 



Time of Doy 



16:00 



24:00 



OS.OO 



Fig. 22. Shift in phase of mitotic rhythms in liver parenchyma and 

 pinnal epidermis, after inversion of lighting regimen in mouse. (° Based 

 upon logio transformation of counts.) 



