PMID- 21059030
OWN - NLM
STAT- MEDLINE
DCOM- 20110817
LR  - 20131121
IP  - 38
DP  - 2010 Nov
TI  - Dietary energy source and physical conditioning affect insulin sensitivity and 
      skeletal muscle glucose metabolism in horses.
PG  - 355-60
LID - 10.1111/j.2042-3306.2010.00255.x [doi]
AB  - REASONS FOR PERFORMING STUDY: Starch rich (S) feeds reduce insulin sensitivity in 
      untrained horses when compared to high fat (F) feeds, but insulin sensitivity is 
      not affected when S or F are fed during exercise training. The effects of S vs. F 
      on training-associated alterations in skeletal muscle glucose metabolism are 
      unknown. OBJECTIVES: To determine the effects of dietary energy source on 
      training-associated changes in insulin sensitivity, skeletal muscle GLUT4 protein 
      and hexokinase (HK) and glycogen synthase (GS) activities in horses. METHODS: 
      After a baseline period on an all forage diet (Phase 1), horses were adapted to 
      high starch (S) or high fat (F) diets (n = 7/group) for 6 weeks (Phase 2) and 
      then completed 7 weeks of exercise training (Phase 3) on the same diets. To 
      measure insulin sensitivity (SI), minimal model analysis of a frequently-sampled 
      i.v. glucose tolerance test was performed at the end of each phase. Middle 
      gluteal muscle biopsies to measure GLUT-4 protein content, muscle glycogen and HK 
      and GS activities were taken before and after euglycaemic-hyperinsulinaemic 
      clamps administered after each phase. Data were analysed by repeated measures 
      ANOVA. RESULTS: In S, SI was 36% lower (P < 0.05) after Phase 2 when compared to 
      Phase 1 but was unchanged in F. After Phase 3, SI was increased (P < 0.01) in S 
      and F compared to Phase 2 and did not differ (P > 0.05) between diets. Middle 
      gluteal muscle GLUT-4 protein and post clamp HK activity were increased (P < 
      0.05) in S after Phase 3, with higher (P < 0.01) GLUT4 in S than in F. GS 
      activities were unchanged in both diets. CONCLUSIONS: Adaptation to S resulted in 
      decreased SI mitigated by moderate physical conditioning. Increased GLUT-4 
      protein content and HK activity in S may have contributed to higher SI after 
      training.
CI  - (c) 2010 EVJ Ltd.
FAU - Stewart-Hunt, L
AU  - Stewart-Hunt L
AD  - Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, 
      Canada.
FAU - Pratt-Phillips, S
AU  - Pratt-Phillips S
FAU - McCutcheon, L J
AU  - McCutcheon LJ
FAU - Geor, R J
AU  - Geor RJ
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Equine Vet J Suppl
JT  - Equine veterinary journal. Supplement
JID - 9614088
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Dietary Fats)
RN  - 0 (Glucose Transporter Type 4)
RN  - 0 (Insulin)
RN  - IY9XDZ35W2 (Glucose)
SB  - IM
MH  - Animal Feed/analysis
MH  - Animal Nutritional Physiological Phenomena
MH  - Animals
MH  - Diet/*veterinary
MH  - Dietary Carbohydrates/pharmacology
MH  - Dietary Fats/pharmacology
MH  - Female
MH  - Gene Expression Regulation
MH  - Glucose/*metabolism
MH  - Glucose Transporter Type 4/genetics/metabolism
MH  - Horses/*physiology
MH  - Insulin/*metabolism
MH  - Male
MH  - Muscle, Skeletal/drug effects/*metabolism
MH  - Physical Conditioning, Animal/*physiology
EDAT- 2011/05/27 06:00
MHDA- 2011/08/19 06:00
CRDT- 2010/11/10 06:00
PHST- 2010/11/10 06:00 [entrez]
PHST- 2011/05/27 06:00 [pubmed]
PHST- 2011/08/19 06:00 [medline]
AID - 10.1111/j.2042-3306.2010.00255.x [doi]
PST - ppublish
SO  - Equine Vet J Suppl. 2010 Nov;(38):355-60. doi: 10.1111/j.2042-3306.2010.00255.x.