| RESEARCH PAPER
|Year : 1999 | Volume
| Issue : 5 | Page : 340-344
Calcium entry into myometrial cells is inhibited by tamoxifen and 4-monohydroxytamoxifen
MJ Wilkinson, Anthony Lipton
Objectives: To investigate whether tamoxifen, oestradiol and 4-monohydroxytamoxifen inhibit entry of calcium into rat myometrium.
Methods: Pieces of myometrium were incubated in media containing tamoxifen, oestradiol or 4- monohydroxytamoxifen, in the presence or absence of known myometrial spasmogens (80 mM KCl or 1.28 nM oxytocin). Following incubation the tissues were dried and the uptake of 45 Ca 2+ measured.
Results: OH-tamoxifen inhibited the entry of 45 Ca 2+ entry in both normal (5.9 mM KCl) and high potassium (80 mM KCl) media while tamoxifen and oestradiol inhibited 45 Ca 2+ entry only in high potassium media. 20 (M 17(-oestradiol also inhibited calcium influx in oxytocin (1.28 nM) stimulated tissues, no inhibition was observed with tamoxifen.
Conclusions: Tamoxifen and its metabolite, 4-monohydroxytamoxifen (OH-tamoxifen) may obstruct ion-channel, but not receptor, mediated entry of calcium into rat myometrium.
M J Wilkinson
Source of Support: None, Conflict of Interest: None