Fibroblast growth factor-16 is a growth factor for embryonic brown adipocytes.
In rat embryos, fibroblast growth factor (FGF)-16 is predominantly expressed in brown adipose tissue. To elucidate the role of FGF-16, we examined the expression of FGF-16 mRNA in rat embryonic brown adipose tissue at different developmental stages by Northern blotting analysis and in situ hybridization. FGF-16 mRNA was expressed abundantly in brown adipose tissue during embryonic day 17. 5, embryonic days 17.5-19.5, and thereafter at lower levels into the neonatal period. The expression profile of FGF-16 mRNA well corresponds to the proliferative profile of embryonic brown adipose tissue reported. We also examined the mitogenic activity of recombinant rat FGF-16 for primary brown adipocytes prepared from rat embryonic brown adipose tissue. FGF-16 showed significant mitogenic activity for primary brown adipocytes. The mitogenic activity was found to be exerted by binding and activating FGF receptor-4 in the brown adipose tissue. As a great induction of proliferation of rat brown adipose tissue during cold acclimation was reported, we also examined the expression of FGF-16 mRNA in the brown adipose tissue during cold acclimation by Northern blotting analysis. The expression of FGF-16 mRNA was not increased, but rather decreased. The expression profile of FGF-16 mRNA and the mitogenic activity of FGF-16 reported here indicate that FGF-16 is a unique growth factor involved in proliferation of embryonic brown adipose tissue.
Konishi
M
M
Department of Genetic Biochemistry, Kyoto University Graduate School of Pharmaceutical Sciences, Sakyo, Kyoto 606-8501, Japan.
Mikami
T
T
Yamasaki
M
M
Miyake
A
A
Itoh
N
N
D002001:Adipose Tissue, Brown / Q000196:embryology*; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002455:Cell Division; D003080:Cold Temperature; D005346:Fibroblast Growth Factors / Q000502:physiology*; D017403:In Situ Hybridization; D007473:Ion Channels; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014475:Uncoupling Agents / Q000378:metabolism; D000071256:Uncoupling Protein 1
D002352:Carrier Proteins; C110776:Fgf16 protein, rat; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; D014475:Uncoupling Agents; D000071256:Uncoupling Protein 1; D005346:Fibroblast Growth Factors