title: The effect of chronic underfeeding on organ weights of rats. How to interpret organ weight changes in cases of marked growth retardation in toxicity tests?
abstract: Growing male rats were kept on a restricted feed intake. After 13 weeks they reached a final body weight of 250 g in comparison with 366 g of their ad lib. fed controls. The relative weights of the heart, kidneys, spleen, pituitary and prostate/seminal vesicle were not altered by underfeeding. The relative weights of the brain, adrenals and tests were increased by 30 to 40% in the feed-restricted groups, the thyroid by about 20%. The relative weight of the liver was decreased by about 30%. When growth is markedly reduced in a toxicity experiment alterations of this kind in the organ weight: body weight ratios have to be expected as a physiological response of the organism to decreased feed intake. They must be differentiated from organ weight changes resulting from primary toxic influences of the drug tested.
mesh_terms: D000367:Age Factors; D000818:Animals; D001835:Body Weight; D006130:Growth Disorders / Q000503:physiopathology*; D008297:Male; D009748:Nutrition Disorders / Q000503:physiopathology*; D009929:Organ Size / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors