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Effect of central application of 17‐β estradiol on thermoregulation during a cold exposure in female rats
Author(s) -
Uchida Yuki,
Tokizawa Ken,
Nagashima Kei
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.956.14
Subject(s) - ovariectomized rat , thermoregulation , medicine , endocrinology , hypothalamus , estrogen , preoptic area , estrogen receptor , chemistry , cancer , breast cancer
BACKGROUND We reported that, in ovariectomized rats, thermoregulation in the cold was attenuated. However, systemic administration of 17‐β estradiol (E 2 ) restored the response. Moreover, E 2 increased cFOS immunoreactive cells in the medial preoptic area (MPO) and dorsomedial hypothalamus (DMH) in the cold. PURPOSE To test the hypothesis that E 2 augments central thermosensitivity to the cold, we assessed the effect of the local administration of E 2 to the two hypothalamic areas on body temperature (T b ) in the cold. METHODS Adult female rats were ovariectomized, and a stainless steel canula was placed in the MPO, DMH, or horizontal limb diagonal band. At least 7 days after the surgery, E 2 or cholesterol was administrated to this brain area through the canula. Forty‐eight hours after the administration, a rat was exposed to 10°C or 25°C environment for 2h, and T b was measured by telemetry. RESULTS During the 10°C exposure, T b increased only in the group, which was administrated E 2 in the MPO. Either cholesterol nor E 2 in the other brain area had no effect on T b . CONCLUSION The MPO has abundant estrogen receptors and so‐called thermosensitive neurons, estrogen may modulate thermosensitivity to the cold in the MPO.