The direct luteotropic effect of tokishakuyakusan in rats.

The effect of Tokishakuyakusan (TS) on the corpus luteum function in pseudopregnant rats was examined in vivo. On day 4 of pseudopregnancy (PSP), induced by cervical stimulation, TS (20 micrograms) stimulated the progesterone secretion rate (PSR) in the ovarian venous plasma. There was also a significant increase in the rate of progesterone to 20 alpha-OH-progesterone. However, on day 8 of PSP, there was no apparent change in PSR in the ovarian venous plasma after the administration of TS. These data suggest that the sensitivity to TS of the corpus luteum varies according to its age.