In vivo inhibition of basal and estrogen-induced phospholipase A2 activities by the triphenylethylene antiestrogen, tamoxifen, in immature quail oviduct.

ABSTRACT

The effects of tamoxifen on oviductal phospholipase A2 activity were studied in immature quails. Injected alone, from 0.1 to 10 mg/kg tamoxifen significantly reduced basal phospholipase A2 activity 6 h after the injection, independently of the dose used. At 24 h, maximal inhibition (-50%) was observed with 0.1 mg/kg tamoxifen, while higher doses were less effective. Combined with estradiol benzoate, tamoxifen reduced even below the control value (1 mg/kg for 24 h) the increase in phospholipase A2 activity induced by estrogen.