[The effect of Shakuyaku-kanzo-to on prostaglandin production in human uterine myometrium].

Shakuyaku-kanzo-to (SK), a Chinese herb medicine consisting of Shakuyaku (Paeoniae Radix) and Kanzo (Glycyrrhizae Radix) has been used for the treatment of dysmenorrhea. It is reported that prostaglandin (PG) production increased during menstruation in uterine myometrium. To know the effect of SK on PG production in the uterine myometrium, the following in vitro study was undertaken. Human uterine myometrium was obtained from patients who underwent hysterectomy. 1. Myometrial cells were cultured and, SK, Shakuyaku (S), Kanzo (K), or glycyrrhetinic acid (GA), which is the major component of K, were added to the culture medium. Concentrations of PGE2, PGF2 alpha, and 6-ketoPGF1 alpha in the medium measured by RIA were significantly decreased by the addition of SK, K or GA but no effect was observed when S. 2. [3H]-arachidonic acid (AA) was added to culture medium and incorporated into the Sn-2 of phospholipids. [3H]-AA release and PG production in the medium were determined. PG were extracted and the radioactivity of PG was measured. The production of PGE2, PGE2 alpha and 6-ketoPGF1 alpha from labeled cells was significantly reduced by the addition of SK, K and GA. 3. Phosphatidylcholine containing [14C]-AA in Sn-2 (150,000 dpm) was incubated with cytosol of uterine myometrium and the amounts of [14C]-AA released were calculated as Phospholipase A2 activity. The amount of [14C]-AA release was inhibited dose-dependently by SK, K and GA. It is the first time that SK has been shown to suppress PG production in the myometrium by inhibiting cPLA2 activity.