Expression profiles of three isoforms of inositol 1,4,5-trisphosphate receptor in brown adipose tissue of the rat.
The thermogenic function of brown adipose tissue (BAT) is known to be mainly regulated by a signal transduction cascade via beta-adrenoceptor. However, recent studies indicated that the alpha-adrenoceptor and its downstream signal transduction cascade, causing elevation of the cellular Ca(2+) level, are also important for the regulation of this function of BAT. In the present study, expression profiles of 3 isoforms of the inositol 1,4,5-trisphosphate (IP(3)) receptor, known as one of the major components of the machinery regulating the intracellular Ca(2+) concentration in the BAT of rats, were investigated by Northern analysis. Of these three IP(3) receptor isoforms, the type 2 one was found to be the most abundant of the three in BAT. Furthermore, when rats were exposed to the cold, under which condition the thermogenic function of BAT is known to be stimulated, the expression levels of types 1 and 2 isoforms of IP(3) receptor were remarkably elevated. The results of Western analysis supported the predominant expression of the type 2 isoform in BAT. However, different from the results of Northern analysis, the expression levels of types 1 and 2 isoforms of IP(3) receptor protein in BAT were not influenced by exposure of the animals to the cold.
Kajimoto
Kazuaki
K
Faculty of Pharmaceutical Sciences, University of Tokushima, Shomachi-1, Tokushima 770-8505, Japan.
Daikoku
Takiko
T
Yamazaki
Naoshi
N
Terada
Hiroshi
H
Shinohara
Yasuo
Y
D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D015152:Blotting, Northern; D015220:Calcium Channels / Q000096:biosynthesis*; D004734:Energy Metabolism; D020869:Gene Expression Profiling; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008297:Male; D020033:Protein Isoforms / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis*
D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D020033:Protein Isoforms; D018160:Receptors, Cytoplasmic and Nuclear