Abstract
We have previously confirmed that lipid metabolism in experimental animals is affected by exposure to noise. The present study was conducted to investigate the effects of non-noise or noise exposure on lipid and nitrogen metabolism in rats fed a porcine plasma peptide diet. Male Wistar rats (100-120g) were fed either a 25%casein diet (group C), or a porcine plasma peptide diet in which half of the casein was replaced by porcine plasma peptide. The latter animals were subdivided into non-noise (grouP) and noise exposure (group P-N) groups. Rats in group P-N were exposed to noise of 3, 000Hz, 95 phone for 8h per day. Al1 the animals were fed the experimental diets ad libitum for one week. Serum and liver cholesterol, triglyceride and TBA values, and urinary nitrogen and corticosterone excretions were then determined. Food consumption in group P was higher than that in group C or P-N, but body weight gain did not differ among the three groups. Serum total cholestero1, and urinary corticosterone excretion in group P-N were increased significantly compared with group P. However, liver total cholesterol, triglyceride and the TBA value in group P-N were lower than those in group P, The ratio of urinary N excretion/N intake (%) in group P-N had a tendency to be higher than that in group P, but there was no significant difference between the two groups.
