Diurnal variations in the number of granulosa cells synthesizing DNA in relation to follicle size in the mouse ovary

Summary Autoradiographs of mouse ovaries prepared after pulse-labelling with ³H-thymidine at 4-hourly intervals over a 24-hour period show, that in the early stages of follicle development there is a diurnal variation in the number of granulosa cells synthesizing DNA. This is not found in later stages.The diurnal variations are correlated with low proliferation rates of the cell populations and with growth fractions below one.It is concluded, that diurnal variations in the number of granulosa cells synthesizing DNA are due to variations in the growth fractions of the granulosa cell populations.