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Administration of 17‐ β estradiol in the medial preoptic area prevents reduction of body temperature during cold exposure in ovariectomized rats
Author(s) -
Uchida Yuki,
Tohi Madoka,
Tokizawa Ken,
Nagashima Kei
Publication year - 2009
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.23.1_supplement.788.15
Subject(s) - ovariectomized rat , endocrinology , medicine , chemistry , estrogen , core temperature , brown adipose tissue , adipose tissue
BACKGROUND We reported that ovariectomized rats could not maintain body temperature (T core ) well in the cold; however, local administration of 17‐β estradiol (E 2 ) in the medial preoptic area (MPO) restored the cold intolerance. The E 2 administration had no effect on UCP1 mRNA level in the interscapular brown adipose tissues, suggesting less influence on metabolic heat production. PURPOSE To test the hypothesis that the local E 2 administration in the MPO affects heat dissipation, the tail surface temperature was assessed by thermography. METHODS After ovariectomy for 9‐wk old rats, a stainless steel canula was placed in the MPO for local administration of E 2 or cholesterol. A rat was placed at 10 or 25°C for 2h, 48 h after the administration E 2 or cholesterol. T core and tail temperature (T tail ) were measured by telemetry and thermography. RESULTS Both the groups showed decrease in T tail at 10°C; however the reduction was greater in the estrogen group than in the cholesterol group. CONCLUTION Without estrogen in the MPO, heat dissipation from the tail in ovariectomized rats may not be fully suppressed in the cold, resulting in reduction of T core.