Monograph on the Potential Human Reproductive and ... - OEHHA

370 CHAPIN ET AL.
weeks before mating and during a 2-week mating period.
Exposures of males continued through the gestation period
of the litters they sired. Exposures of females continued
through the gestation and lactation period. During the
study, adult animals were monitored for clinical signs of
toxicity, body weight, and food intake.
Estrous cycles were evaluated in F0 and F1 females
during the last 3 weeks of the pre-breeding exposure
period. Day of vaginal plug was defined as GD 0 and day
of birth was considered PND 0. F 1 and F 2 pups were
counted, sexed, weighed, and assessed for viability and
physical abnormalities at birth and throughout the
lactation period. Anogenital distance was measured in
F1 and F2 pups at birth and on PND 21. On PND 4, F1 and
F2 litters were standardized to 10 pups, with equal
numbers per sex when possible. Pups removed on PND 4
were killed and examined for visceral alterations, with a
focus on the reproductive system. The remaining pups
were maintained and weaned on PND 21. At weaning, 28
F1 pups/sex/group (1 per sex per litter) were randomly
selected for mating and those animals were referred to as
parental mice. An additional F1 male/litter was selected
for a 3-month exposure (referred to as retained males).
Two F1 pups/sex/litter were selected for gross necropsy
and organ weight measurement at weaning. Histopathological
examination of reproductive organs was conducted
in one PND 21 pup/sex/litter. Histopathological
evaluation of reproductive and systemic organs were
conducted in the second F1 pup from each group at
weaning. All F2 pups were killed at weaning and organ
weights were measured. Vaginal opening and preputial
separation were monitored in parental and retained F1
mice. Parental F 0 and F 1 males were killed following
delivery of the litters they sired. Retained F 1 males were
killed at the same time as the parental F 1 males. Parental
F0 and F1 females were killed after their pups were
weaned. Organs, including those of the reproductive
system, were weighed in adult F0 and F1 animals.
Histopathological evaluations were conducted in all
animals from the vehicle control group, in 10 F0 and F1
parental animals from each treatment group, in all F 1
retained males, and 10 animals from the 17b-estradiol
positive control group. Histopathological evaluation of
reproductive organs was also conducted in animals with
suspected reduced fertility. Testes were preserved in
Bouin fixative. Daily sperm production, efficiency of
daily sperm production, and epididymal sperm count,
motility, and morphology, were evaluated in F0 and F1
males. Data from the 2 control groups were analyzed
separately and then pooled for statistical analysis of
treatment groups. Statistical analyses included ANOVA,
Levene test, robust regression methods, Wald w 2 test, ttest,
Dunnett test, Fisher exact probability test, and
ANCOVA.
Treatment- or dose-related results and observations in
reproductive organs of adult animals are summarized in
Table 98. There were no consistent effects on body weight
or body weight gain in F 0 males. Body weight gain
during lactation was increased in F 0 females from the
3500 ppm group. During the premating period, body
weights were decreased by r10% in F1 parental animals
from the 3500 ppm group (study days 0, 7, 49, and 56 in
males and study 0 in females). In retained F1 males from
the 3500 ppm group, body weights were decreased at
most time periods between study days 7 and 84 and at
necropsy. No consistent or dose-related changes in feed
intake or efficiency were observed throughout the study
in F 0 or F 1 animals. There were no clinical signs of
toxicity or treatment-related deaths in F0 or F1 males or
females. Increases in absolute and relative to body or
brain weights of kidney and liver were consistently
observed in F0 and F1 adults. Significant and dose-related
organ weight changes relative to body weight are
summarized in Table 98. Other effects on organ weight
(e.g., seminal vesicles, epididymides, coagulating glands,
and pituitary) were not considered to be treatmentrelated
by study authors due to factors such as lack of a
dose–response relationship, no consistency between
absolute and relative weights, no histopathology, or no
consistency across generations. Absolute and relative
prostate weights were unaffected by bisphenol A
exposure. There were no treatment-related gross systemic
findings in F 0 or F 1 adults. Incidence of minimal to
mild hepatocyte centrilobular hypertrophy was increased
in both generations at 300 and/or 3500 ppm
(Table 98). Renal nephropathy incidence was increased in
F0 males and in F1 males and females of the 3500 ppm
group. [It did not appear that histopathological data
were statistically analyzed.]
Treatment- or dose-related reproductive effects in
adult animals are summarized in Table 98. Bisphenol A
exposure had no effect on numbers of implantation sites
or resorptions or on mating, fertility, or gestational
indices in F0 or F1 mice. Gestational length was increased
in F0 and F1 females from the 3500 ppm group; the study
authors stated the effect was of unknown biological
significance. Epididymal sperm concentration was decreased
in F 0 males of the 3500 ppm group but no effect
was observed in F 1 parental or retained males. There was
no effect on daily sperm production, efficiency of daily
sperm production, or sperm motility or morphology in
either generation. The study authors did not consider the
decrease in sperm concentration in F0 animals to be
treatment-related based on lack of consistency between
generations, no effect on any other andrological endpoint,
and no effect on fertility. Estrous cyclicity and
numbers of ovarian primordial follicle counts were not
affected by bisphenol A exposure in F 0 or F 1 females. The
only gross observation in reproductive organs was a
slightly increased incidence of gross ovarian cysts in F0
females from the 3500 ppm group. The incidence of
paraovarian cysts was increased in F0 and F1 females
from the 3500 ppm group. [It did not appear that
histopathological data were statistically analyzed.]
Significant findings in developing mice are summarized
in Table 99. Live F 1 and F 2 pups and litters at birth,
sex ratio, and survival during the lactation period were
not affected and there were no clinical or gross signs of
toxicity in F1 or F2 offspring. A non-dose-related decrease
in PND 21 survival index and lactational index (pups
surviving on PND 21/PND 4) was described in F2 pups
of the 300 ppm group. [The biological significance of
the effect was not discussed by the study authors, but
because the effect was not dose-related it is unlikely to
be of biological significance.] In F1 pups from the
3500 ppm group, body weights were reduced during
PND 7, 14, and 21 in F1 females and both sexes combined
and on PND 7 and 21 in F1 males. Body weight results for
both sexes combined are summarized in Table 99. An
increase in male pup body weight observed on PND 7 in
Birth Defects Research (Part B) 83:157–395, 2008