title: Fish oil supplementation for two generations increases insulin sensitivity in rats.
abstract: We investigated the effect of fish oil supplementation for two consecutive generations on insulin sensitivity in rats. After the nursing period (21 days), female rats from the same prole were divided into two groups: (a) control group and (b) fish oil group. Female rats were supplemented with water (control) or fish oil at 1 g/kg body weight as a single bolus for 3 months. After this period, female rats were mated with male Wistar rats fed on a balanced chow diet (not supplemented). Female rats continued to receive supplementation throughout gestation and lactation periods. The same treatment was performed for the next two generations (G1 and G2). At 75 days of age, male offspring from G1 and G2 generations from both groups were used in the experiments. G1 rats did not present any difference with control rats. However, G2 rats presented reduction in glycemia and lipidemia and improvement in in vivo insulin sensitivity (model assessment of insulin resistance, insulin tolerance test) as well as in vitro insulin sensitivity in soleus muscle (glucose uptake and metabolism). This effect was associated with increased insulin-stimulated p38 MAP kinase phosphorylation and lower n-6/n-3 fatty acid ratio, but not with activation of proteins from insulin signaling (IR, IRS-1 and Akt). Global DNA methylation was decreased in liver but not in soleus muscle. These results suggest that long-term fish oil supplementation improves insulin sensitivity in association with increased insulin-stimulated p38 activation and decreased n-6:n-3 ratio in skeletal muscle and decreased global DNA methylation in liver.
authors.affiliation: Institute of Physical Activity Sciences and Sport, Cruzeiro do Sul University, São Paulo, Brazil. sandromh@yahoo.com.br
authors.forename: Sandro M
authors.initials: SM
authors.lastname: Hirabara
authors.forename: Alessandra
authors.initials: A
authors.lastname: Folador
authors.forename: Jarlei
authors.initials: J
authors.lastname: Fiamoncini
authors.forename: Rafael H
authors.initials: RH
authors.lastname: Lambertucci
authors.forename: Carlos F
authors.initials: CF
authors.lastname: Rodrigues
authors.forename: Marlene S
authors.initials: MS
authors.lastname: Rocha
authors.forename: Julia
authors.initials: J
authors.lastname: Aikawa
authors.forename: Ricardo K
authors.initials: RK
authors.lastname: Yamazaki
authors.forename: Amanda R
authors.initials: AR
authors.lastname: Martins
authors.forename: Alice C
authors.initials: AC
authors.lastname: Rodrigues
authors.forename: Angelo R
authors.initials: AR
authors.lastname: Carpinelli
authors.forename: Tania C
authors.initials: TC
authors.lastname: Pithon-Curi
authors.forename: Luiz C
authors.initials: LC
authors.lastname: Fernandes
authors.forename: Renata
authors.initials: R
authors.lastname: Gorjão
authors.forename: Rui
authors.initials: R
authors.lastname: Curi
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D019175:DNA Methylation; D019587:Dietary Supplements; D015525:Fatty Acids, Omega-3 / Q000378:metabolism; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage* / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D051057:Proto-Oncogene Proteins c-akt; D048051:p38 Mitogen-Activated Protein Kinases