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EC number: 235-252-2
CAS number: 12141-20-7
The relative weights of male secondary sex organs in adult offspring
were not significantly affected in any of the lead-treated groups. In
contrast, female pups exposed to lead form birth through adulthood or
from gestational day 5 through adulthood were observed to have
significantly delayed vaginal opening and disrupted estrus cycling.
These effects on female reproductive physiology were not observed in
animals where lead exposure was confined only to pregnancy and
lactation. Significant suppression of adult mean serum testosterone
levels was only observed in male pups exposed to lead continuously from
gestational age 5 days throughout life. Lead decreased birth weight in
all animals exposed in utero and mean body weights were significantly
decreased in all lead treated groups up to weaning. Analysis of growth
curves revealed that all lead-treated groups had significantly reduced
growth rates during lactation. However, in addition, male pups exposed
to lead during pregnancy and lactation, from birth or gestational age 5
days, growth rates were also significantly reduced during puberty.
Postpubertal growth rates were unaffected in any lead-treated group.
Thus, delayed female reproductive development and suppression of adult
male serum testosterone concentration required continuous exposure to
the heavy metal. Little evidence was observed for an alteration of
"endocrine imprinting" by lead on either reproductive or growth
parameters. Exposure during development (pregnancy and lactation)
resulted in no permanent effects in this model other than small (10%)
decreases in the body weight of pups postpuberty.
Effects of lead on Vaginal Opening and Estru Cycling in Female Offspring
Effects of gestational lead exposure on offspring
Positive Effects of lead on male secondary sex organ weights in
offspring at age 85 days
The reproductive, endocrine, and growth effects of developmental lead
exposure were assessed using a rat model in which 0.6% lead acetate
(w/v) was administered in the drinking water ad libitum during different
developmental periods to determine if lead actions were a result of
direct effects of continuous exposure to the metal ion or secondary to
disrupted neonatal "endocrine imprinting." Sprague Dawley rats were
exposed to lead: (1) from gestational day 5 through birth; (2) during
pregnancy and lactation; (3) during lactation only ; (4) from birth
through adulthood; (5) from gestational day 5 through adulthood. lead
effects were measured on the development of aspects of the reproductive
system, adult sex steroid levels, and growth rates, in both male and
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