||Morphometric and Electron Microscopic Analysis of Hepatic Changes in Rats Dosed with Octamethylcyclotetrasiloxane (d4) by Oral Gavage with Cover Sheets & Letter Dated 01/09/1992.
||Dow Chemical Co., Midland, MI.; Environmental Protection Agency, Washington, DC. Office of Toxic Substances.
Health effects ;
Octamethylcyclotetrasiloxane (556-67-2) ;
Subchronic Toxicity ;
Toxic substances ;
Laboratory animals ;
CAS No 556-67-2
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
||This study evaluated hepatic changes in rats administered dimethylcyclosiloxane fluid. Two groups of male CD rats (10 per group) were administered 0 or 1600 mg dimethylcyclosiloxane fluid/kg/day by gavage for 14 days. Two additional groups received the same treatment but were examined using a DNA assay not discussed here. The animals were observed for mortality, other signs of toxicity, and changes in food consumption. In addition, the animals were weighed prior to study initiation, on day 7, and prior to terminal sacrifice. After the treatment period all surviving animals were sacrificed and the livers weighed, fixed using perfusion fixation, and prepared for examination via light and electron microscopy. Morphometric examination of the livers included determination of the total number of cells per liver, number of cells per volume of liver, and the average diameter of cell profiles in each lobular zone. No changes in body weight or food consumption, no deaths, and no signs of toxicity were observed. No difference in the number of cells per volume of liver was reported. However, the was a significant increase in the number of hepatocytes and in the total volumes of the livers of the treated group. In addition, liver weights of the treated animals were significantly increased relative to controls. No significant differences in mean hepatocyte diameter were observed, indicating hepatocellular hypertrophy was not present. These findings suggest that hyperplasia was the cause of hepatomegaly in rats exposed to dimethylcyclosiloxane fluid.
||The quality of the documents listed in the Office of Toxic Substances database may not meet usual NTIS standards but are included to further the opportunity for the scientific and technical community to locate materials which may not be available elsewhere. The content is the responsibility of OTS. Sponsored by Environmental Protection Agency, Washington, DC. Office of Toxic Substances.
||Product reproduced from digital image. Order this product from NTIS by: phone at 1-800-553-NTIS (U.S. customers); (703)605-6000 (other countries); fax at (703)605-6900; and email at email@example.com. NTIS is located at 5285 Port Royal Road, Springfield, VA, 22161, USA.
|PUB Date Free Form
||57Y; 57U; 68G; 99; 44G
||PC A04/MF A04