4-WEEK REPEATED INHALATION STUDY OF HCFC 225CA AND HCFC 225CB IN THE COMMON MARMOSET

Four male and three female marmosets in each group were exposed to air only, 1000 ppm of HCFC 225ca or 5000 ppm of HCFC 225cb, for 6 h per d ay for 28 consecutive days. HCFC 225ca caused a slight reduction in bo dy weight. HCFC 225cb occasionally caused somnolence during exposure a nd vomiting on the first day of exposure. Clinical chemistry findings included a mild reduction of triglyceride, cholesterol and phospholipi d levels and increased GOT level in the HCFC 225ca exposure group. HCF C 225cb also caused a reduction of triglyceride levels in some animals . HCFC 225ca caused a slight increase of hepatic carnitine palmitoyltr ansferase (CPT) activity while HCFC 225cb slightly increased cyanide-i nsensitive palmitoyl CoA beta-oxidation (FAOS) activity. In the HCFC 2 25cb exposure group, an increase in cytochrome P-450 content was also observed. HCFC 225ca caused a fatty change in the hepatic cells. Incre ased incidence of lipid droplets in the hepatic cells and myelin-like bodies in hepatic cells, Kupffer's cells and hepatic blood vessels wer e observed electron microscopically in the HCFC 225ca exposure group. A proliferation of smooth endoplasmic reticulum was observed in the HC FC 225cb exposure group. Decreased peroxisome volume density in the HC FC 225ca group, and increased volume density in the HCFC 225cb exposed females were seen. However, organ weight measurement and histopatholo gical examination did not reveal hepatomegaly or hypertrophy with eith er substance. Although slight changes were noticed in peroxisome volum e density and in some of the peroxisomal enzyme activities, the change s related to peroxisome proliferation with HCFC 225ca and 225cb were m inimal in marmosets compared to those seen in rats. Histopathological examination and hormonal analysis did not reveal any abnormalities in the pancreas or testes. (C) 1997 Elsevier Science Ltd.