Elevation of tail skin temperature in ovariectomized rats in relation to menopausal hot flushes

Menopausal hot flushes (HFs), which manifest as an increase in skin tempera ture, most frequently occur after menopause and cease with the passage of t ime. We designed this study to elucidate the characteristics of the elevati on of tail skin temperature (TST) in ovariectomized (OVX) rats, which is re levant to human symptoms of HFs. First, we measured TST and rectal temperat ure (RT) and investigated the time course of their changes up to 20 wk afte r ovariectomy. The TST in OVX rats (28.4 +/- 0.3 degrees C) was significant ly (P = 0.0035) elevated from 2 to 7 wk after the ovariectomy compared with that in sham-operated (Sham) rats (27.0 +/- 0.2 degrees C), whereas the RT in OVX rats was elevated from 8 to 20 wk. We next examined the therapeutic effects of estradiol (E-2) On the elevation of the TST by continuous subcu taneous infusion. Ea treatment (1.0 mu g/day) completely (P = 0.0232) inhib ited the elevation of the TST (28.4 +/- 0.3 degrees C for Sham rats, 29.3 /- 0.3 degrees C for OVX rats, 28.2 +/- 0.1 degrees C for OVX + E-2 1.0 mu g/day rats). These results demonstrated that the elevation of TST in OVX ra ts was exhibited soon after the estrogen removal and diminished with time a nd that it was normalized with continuous E-2 replacement. These characteri stics are similar to the symptoms of menopausal HFs in women.