[Effects of pectin and cellulose on somatomedin C levels and proteoglycan synthesis rate in rat muscle and cartilage].
The inclusion of 15% pectin in a diet causes growth retardation in rats, but the mechanism for the impaired growth has not been established. Serum concentration of IGF-I and proteoglycan synthesis rate on muscle and the tibial epiphysis, an estimate of biological response to IGF-I in a target tissue, were compared in weaning rat fed with 8.5% protein and levels of 7.5 and 15% of pectin and cellulose, respectively. In experiment 1 (G1-G6) was used cellulose as source of fiber and in experiment 2 (G7-G11) pectin. A marked reduction in weight, muscle and bone growth was observed for the groups fed on 15% pectin. Plasma IGF-I concentration correlated with both protein and tibial proteoglycan synthesis rate in the group with 15% pectin diet. However, in the group fed with cellulose the most of the parameters were well maintained, with exception the group fed with beans and rice (G5 e G6). Our study suggest that the inclusion of pectin in a experimental diet impairs growth by a combination of reduced food intake, a reduced anabolic response to food due to a reduced protein and proteoglycan synthesis possibly reflecting impaired IGF-I action and secretion.
Departamento de Alimentos e Nutrição Experimental, Faculdade de Ciêucias Farmacêuticas, Universidade de São Paulo, Brasil.
J
J
Tirapegui
G
G
Silva
K
K
Bruscatto
A P
AP
Silvatti
S T
ST
Osuka
D000818:Animals; D002356:Cartilage / Q000378:metabolism*; D002482:Cellulose / Q000494:pharmacology*; D005503:Food Additives / Q000494:pharmacology*; D006128:Growth / Q000187:drug effects; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D009132:Muscles / Q000378:metabolism*; D010368:Pectins / Q000494:pharmacology*; D011509:Proteoglycans / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar
D005503:Food Additives; D011509:Proteoglycans; D007334:Insulin-Like Growth Factor I; D010368:Pectins; D002482:Cellulose