REGULATION BY ESTROGENS OF TACHYKININ NK3 RECEPTOR EXPRESSION IN THE RAT UTERUS

The expression of the tachykinin NK3 receptor and its regulation by ov arian steroids were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) in uteri from ovariectomized rats. A single transcr ipt corresponding to the 325-bp product expected for the tachykinin NK 3 receptor was detected in uteri from olive oil-treated (control) ovar iectomized rats. The level of tachykinin NK3 receptor mRNA in progeste rone-treated animals was similar to that observed in uteri from contro l ones. Tachykinin NK3 receptor mRNA levels were significantly smaller in uteri from oestrogen-treated ovariectomized rats, with approximate ly a 32-fold decrease. These findings suggest that oestrogen, but not progesterone, regulates the expression of tachykinin NK3 receptors in the rat uterus.