TY - JOUR
T1 - Expression of a chimeric retroviral-lipase mRNA confers enhanced lipolysis in a hibernating mammal
AU - Bauer, Vernon W.
AU - Squire, Teresa L.
AU - Lowe, Mark E.
AU - Andrews, Matthew T.
PY - 2001
Y1 - 2001
N2 - Hibernating mammals can survive several months without feeding by limiting their carbohydrate catabolism and using triacylglycerols stored in white adipose tissue (WAT) as their primary source of fuel. Here we show that a lipolytic enzyme normally found in the gut, pancreatic triacylglycerol lipase (PTL), is expressed in WAT of hibernating 13-lined ground squirrels (Spermophilus tridecemlineatus). PTL expressed in WAT is encoded by an unusual chimeric retroviral-PTL mRNA ∼500 bases longer than the predominant PTL message found in other ground squirrel tissues. Seasonal measurements detect the chimeric mRNA and PTL enzymatic activity in WAT before and during hibernation, with both showing their lowest observed levels 1 wk after hibernation concludes in mid-March. PTL is expressed in addition to hormone-sensitive lipase, the enzyme typically responsible for hydrolysis of triacylglycerols in WAT. Because of the distinct catalytic and regulatory properties of both enzymes, this dual-triacylglycerol lipase system provides a means by which the fuel requirements of hibernating 13-lined ground squirrels can be met without interruption.
AB - Hibernating mammals can survive several months without feeding by limiting their carbohydrate catabolism and using triacylglycerols stored in white adipose tissue (WAT) as their primary source of fuel. Here we show that a lipolytic enzyme normally found in the gut, pancreatic triacylglycerol lipase (PTL), is expressed in WAT of hibernating 13-lined ground squirrels (Spermophilus tridecemlineatus). PTL expressed in WAT is encoded by an unusual chimeric retroviral-PTL mRNA ∼500 bases longer than the predominant PTL message found in other ground squirrel tissues. Seasonal measurements detect the chimeric mRNA and PTL enzymatic activity in WAT before and during hibernation, with both showing their lowest observed levels 1 wk after hibernation concludes in mid-March. PTL is expressed in addition to hormone-sensitive lipase, the enzyme typically responsible for hydrolysis of triacylglycerols in WAT. Because of the distinct catalytic and regulatory properties of both enzymes, this dual-triacylglycerol lipase system provides a means by which the fuel requirements of hibernating 13-lined ground squirrels can be met without interruption.
KW - Hibernation
KW - Pancreatic triacylglycerol lipase
KW - Spermophilus tridecemlineatus
KW - White adipose tissue
UR - http://www.scopus.com/inward/record.url?scp=0034790069&partnerID=8YFLogxK
U2 - 10.1152/ajpregu.2001.281.4.r1186
DO - 10.1152/ajpregu.2001.281.4.r1186
M3 - Article
C2 - 11557627
AN - SCOPUS:0034790069
VL - 281
SP - R1186-R1192
JO - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
JF - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
SN - 0002-9513
IS - 4 50-4
ER -