ABSTRACT
Adult male Sprague-Dawley rats were treated with USP-grade L-tryptophan at a level of 250 mg/kg seven times over 14 d or three times over 3 d by gastric gavage. At autopsy liver specimens were prepared for histological study by stains specific for lipids, for glycoprotein and glycogen, and for fine structure by electron microscopy. Liver lipid did not accumulate as a result of tryptophan treatment. In a series of unfed animals, however, liver lipid had accumulated within 24 h of food withdrawal. Tryptophan has been implicated in fatty liver development by several reports that cite each other, but, in all cases but one, unfed animals were used, and the data show that liver lipid was already present in the unfed animals at the beginning of the experiment. Tryptophan has also been cited as causing abnormal liver morphology, but our evidence suggests that such observations are the result of artifact induced by frozen section preparation and not the result of tryptophan treatment. Our experiments indicate that tryptophan administered to rats at dosages in excess of those recommended for humans does not induce fatty liver or other morphological changes detectable by the methods described.
Subject(s)
Liver/drug effects , Tryptophan/adverse effects , Adrenal Glands/drug effects , Adrenal Glands/pathology , Animals , Esophagus/drug effects , Esophagus/pathology , Gastric Mucosa/drug effects , Gastric Mucosa/pathology , Glycogen/metabolism , Glycoproteins/metabolism , Histocytochemistry , Lipid Metabolism , Liver/pathology , Male , Mucous Membrane/drug effects , Mucous Membrane/pathology , Rats , Rats, Sprague-Dawley , Tryptophan/administration & dosageABSTRACT
The effects of long-term hyperbaric exposure on endocrine organ weight and histology and on epiphyseal-plate width were studied in growing male rats. Six groups of rats were exposed to 21 ATA He-O2 (200 mmHg O2), and six groups were maintained at 1 ATA as room-air controls. Each group contained eight rats. At intervals of of 2, 3, 5, 8, 10, and 12 weeks, one group was decompressed and studied along with a paired control group. Results indicated no changes in pituitary and adrenal gland weights. Testis weights were variable but histology and sperm content were normal. Only the accessory sex organs decreased significantly in weight; however, prostate and seminal vesicle histology were normal. Tibial epiphyseal-plate width was reduced in 21-ATA groups. These results suggest that long-term hyperbaric exposure has little effect on endocrine organs of the rat and observed weight changes are probably related to the reduced body weights.