Biomedical Engineering Reference
In-Depth Information
8 weeks of age). NEDO (1987) noted reduced brain, pituitary, and
thymus weights, and early testicular descent in the offspring of F
0
and
F
1
rats exposed to 1000 ppm methanol. The early testicular descent is
believed to be an indication of earlier fetal development as indicated by
the fact that it was correlated with increased pup body weight. However,
no histopathologic effects of methanol were observed. As discussed in
the report, NEDO (1987) sought to confirm the possible compound-
related effect of methanol on the brain by carrying out an additional
study in which Sprague-Dawley rats were exposed to 0, 500, 1000, or
2000 ppm methanol from the first day of gestation through the F
1
generation. Brain weights were measured in 10-14 offspring/sex/group
at 3, 6, and 8 weeks of age. As illustrated in Table 5.1, brain weights
were significantly reduced in 3-week-old males and females exposed to
1000 ppm. At 6 and 8weeks of age, brain weights were significantly
reduced in males exposed to
1000 ppm and females exposed to
2000 ppm.
The postnatal effects of methanol exposure during late gestation in
Long-Evans rats were studied by Infurna and Weiss (1986). Methanol
was administered at 2% in the drinking water for 3 days from GD 15 to
GD 17 or GD 17 to GD 19. Daily methanol intake averaged about
2.5 g/kg body weight. On PND 1, suckling behavior was tested by
placing the pups with an anesthetized dam and recording the latency to
finding the nipple and beginning to suckle. On PND 10, the ability of the
pups to locate nesting material from their home cage was tested.
Methanol exposure did not affect maternal weight gain or fluid intake;
nor did it affect litter size, birth weight, postnatal survival or growth, or
day of eye opening. Offspring of methanol-exposed dams required
longer than controls to begin suckling on PND 1 (latency of approxi-
mately 90 s vs 60 s in controls). Ability to locate material from the home
nest in a plexiglass grid was also affected in methanol-exposed pups on
PND 10. The methanol-exposed pups required about twice as long as
controls to find their nest material, and their initial direction was more
often incorrect than that of controls.
Stanton et al. (1995) exposed pregnant rats to 15,000 ppm methanol
via inhalation for 7 hour/day on GD 7-19. Daily peak maternal blood
methanol concentrations declined from 3.8mg/ml after
the first
