title: Relative and absolute changes in soluble and insoluble collagen pool size in skin during normal growth and with dietary protein restriction in rats.
abstract: Absolute and relative changes in 0.5M acetic acid soluble and insoluble collagen were followed in the whole skins of young rats fed an adequate diet (18% lactalbumin) for 495 days (n = 92) and a low-protein (3% lactalbumin) diet for 210 days (n = 94). In well-nourished rats, the soluble collagen pool size reached a maximum at approximately 100-140 days of age whereas the insoluble pool tended to increase throughout the period of observation. Thus, the percent soluble collagen increased to a maximum of approximately 80% of total collagen at 40-50 days, thereafter declining progressively to about 20% by 495 days. In contrast, the size of the soluble collagen pool remained constant in protein-restricted rats, but with insoluble collagen increasing linearly throughout, although achieving only a level of about 1/6th of that reached in well-nourished rats. In the restricted rats, percent soluble collagen decreased rapidly and remained at about 25% of total between 80 and 210 days. These data were used to develop prediction equations for the size (mumoles hydroxyproline) of the soluble and insoluble collagen pools in healthy and protein-restricted rats. Hence, where A = days of age, the equations were, respectively: 0.414 X 10(-3) A - 0.390 A2 + 86.9 A - 1800; 0.262 X 10(-2) A3 + 0.793 A2 - 26.5 A + 272; 0.236 A + 155; and 5.07 A - 38.5. These findings are discussed with reference to possible mechanisms responsible for conversion of soluble to insoluble collagens in skin of well-nourished and growth-retarded rats.
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001835:Body Weight; D003094:Collagen / Q000378:metabolism*; D004435:Eating; D007700:Kinetics; D008297:Male; D011488:Protein Deficiency / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012867:Skin / Q000378:metabolism*
chemical_list: D003094:Collagen