title: Effect of ovarian hormones on mitochondrial enzyme activity in the fat oxidation pathway of skeletal muscle.
abstract: To examine the roles of 17beta-estradiol (E(2)) and progesterone (Prog) in lipid metabolism, skeletal muscle enzyme activities were studied in female Sprague-Dawley rats. Groups included sham-operated rats (C) and ovariectomized rats treated with placebo (O), E(2) (E), Prog (P), both hormones at physiological doses (P + E), or both hormones with a high dose of E(2) (P + HiE). Hormone (or vehicle only) delivery was via time-release pellets inserted at the time of surgery, 15 days before metabolic testing. Results demonstrated that carnitine palmitoyltransferase maximal activity was 19, 21, and 19% lower (P < 0.01) in O, P, and P + E rats, respectively, compared with C rats. Conversely, activity in E and P + HiE rats was 14 and 19% higher (P < 0.01) than in C. beta-Hydroxyacyl-CoA dehydrogenase (beta-HAD) maximal activity was 20% lower (P < 0.01) in O than in C rats; similarly, P and P + E rats were 18 and 19% lower, respectively (P < 0.01); however, treatment with E(2) returned beta-HAD activity to C levels. These results suggest that E(2) plays a role in lipid metabolism by increasing the maximal activity of key enzymes in the fat oxidative pathway of skeletal muscle.
authors.affiliation: Exercise Physiology and Metabolism Laboratory, Department of Physiology, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: S E
authors.initials: SE
authors.lastname: Campbell
authors.forename: M A
authors.initials: MA
authors.lastname: Febbraio
mesh_terms: D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000378:metabolism; D000818:Animals; D001835:Body Weight; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004343:Drug Implants; D004958:Estradiol / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005990:Glycerol / Q000097:blood; D007328:Insulin / Q000097:blood; D050356:Lipid Metabolism; D008931:Mitochondria, Muscle / Q000201:enzymology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology*; D010084:Oxidation-Reduction; D005082:Physical Exertion; D011374:Progesterone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D012146:Rest
chemical_list: D004343:Drug Implants; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D011374:Progesterone; D004958:Estradiol; D015094:3-Hydroxyacyl CoA Dehydrogenases; D002334:Carnitine O-Palmitoyltransferase; D002950:Citrate (si)-Synthase; D005990:Glycerol