title: Possible mechanisms by which adipocyte lipolysis is enhanced in exercise-trained rats.
abstract: A possible mechanism(s) behind exercise training-enhanced lipolysis was investigated in rat adipocytes. Exercise training (9 weeks; running) enhanced the activity of cAMP-dependent protein kinase (PKA) and the protein expressions of PKA subunits (catalytic, RII alpha, and RII beta) in P(40) fraction (sedimenting at 40,000g), but not in I(40) fraction (infranatant of 40,000g) of adipocyte homogenate. The expression of PKA-anchoring protein 150 (AKAP150) in P(40) fraction was greater in exercise-trained (TR) than in control (C) rats. Hormone-sensitive lipase (HSL) activities in both fractions were also greater in TR. On the other hand, stimulated lipolysis was accompanied by increased activities of HSL in P(40) but not in I(40) fraction. The decreases in stimulated lipolysis due to St-Ht31 were greater in TR rats. Thus, the mechanisms behind exercise training-enhanced adipocyte lipolysis could involve the increased activities of PKA and HSL with enhanced expressions of AKAP150 and some subunits of PKA, all of which may be compartmentalized within adipocytes.
authors.affiliation: Department of Kinesiology, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Nomura
authors.forename: Hitomi
authors.initials: H
authors.lastname: Kawanami
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ueda
authors.forename: Takako
authors.initials: T
authors.lastname: Kizaki
authors.forename: Hideki
authors.initials: H
authors.lastname: Ohno
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Izawa
mesh_terms: D017667:Adipocytes / Q000378:metabolism*; D000818:Animals; D004789:Enzyme Activation; D008066:Lipolysis; D008297:Male; D010805:Physical Conditioning, Animal; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D002787:Sterol Esterase / Q000378:metabolism; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D011493:Protein Kinase C; D002787:Sterol Esterase