Possible role of fatty acids in milk as the regulator of the expression of cytosolic binding proteins for fatty acids and vitamin A through PPARalpha in developing rats.
Fatty acids in milk are thought to play an important role in intestinal maturation and gene expression in the postnatal small intestine. In this study, we determined the jejunal mRNA levels, in rats, of peroxisome proliferator-activated receptor alpha (PPARalpha) and PPARdelta which are nuclear receptors for fatty acids. We also measured expression of their target genes during the postnatal period, namely liver type fatty acid-binding protein (L-FABP) and cellular retinol-binding protein, type II (CRBPII). The mRNA levels of PPARalpha, L-FABP and CRBPII, but not PPARdelta, gradually increased during the suckling period and then sharply declined to a low level at the end of the weaning period. Rat pups at 17 d of age, weaned to a high-fat diet, showed significantly greater mRNA levels of PPARalpha, L-FABP and CRBPII than those weaned to a low-fat diet. Oral administration of PPARalpha ligand, WY14,643 during four consecutive days of the weanling period caused a parallel increase in the mRNA levels of PPARalpha, L-FABP and CRBPII genes. Furthermore, caprylic acid and oleic acid, which are major components of fatty acids in milk, induced jejunal PPARalpha, L-FABP and CRBPII gene expression. Our results suggest that fatty acids in milk may play a pivotal role in maintaining an enhanced level of expression of L-FABP and CRBPII genes in the small intestine, presumably by acting as inducers of PPARalpha gene expression.
Mochizuki
Kazuki
K
School of Food and Nutritional Sciences, The University of Shizuoka, Shizuoka, Japan.
Mochizuki
Hiroko
H
Kawai
Hiroko
H
Ogura
Yuko
Y
Shimada
Masaya
M
Takase
Sachiko
S
Goda
Toshinao
T
D000818:Animals; D000833:Animals, Suckling; D003600:Cytosol / Q000378:metabolism; D050556:Fatty Acid-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism* / Q000494:pharmacology; D005260:Female; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D007583:Jejunum / Q000502:physiology; D008892:Milk / Q000378:metabolism*; D047493:PPAR alpha / Q000235:genetics / Q000378:metabolism*; D047494:PPAR delta / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D054840:Retinol-Binding Proteins, Cellular / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014801:Vitamin A / Q000378:metabolism*; D014815:Vitamins / Q000378:metabolism*
D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D047493:PPAR alpha; D047494:PPAR delta; D012333:RNA, Messenger; D054840:Retinol-Binding Proteins, Cellular; D014815:Vitamins; D014801:Vitamin A