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

significance of the changes. Weaknesses include use of
the s.c. pump as a route of administration and use of
DMSO as a vehicle.
Utility (Adequacy) for CERHR Evaluation Process:
This study is inadequate for inclusion due to the use of
99.9% DMSO as a vehicle to administer BPA via s.c.
pump. As discussed in earlier, the use of 450% DMSO as
a vehicle for ALZET mini-pump studies is a clear
contravention of the directions for mini-pump use, as it
accelerates the breakdown of the mini-pumps
Naciff et al. (2002), from the Procter and Gamble
Company, examined the effects of prenatal bisphenol A
exposure on gene expression and, to a limited extent,
development in female rat reproductive organs. Pregnant
Sprague–Dawley rats were fed Purina 5K96, a caseinbased
soy- and alfalfa-free diet. [Composition of caging
and bedding materials was not reported.] The rats were
assigned to groups (Z7 rats/group) s.c. injected with
bisphenol A (B99% purity) in DMSO vehicle at 0, 5, 50,
or 400 mg/kg bw/day on GD 11–20 (day of sperm
detection 5 GD 0). Dams were killed on GD 20, and
ovaries and uteri were removed from fetuses. In 4 litters/
group, 1 female fetus/litter was examined for ovarian
and uterine histopathology. In 5 litters/group, ovaries
and uteri from at least 5 littermates were pooled for a
microarray analysis of gene expression. Changes in gene
expression were further quantified using RT-PCR. Data
were analyzed by t-test, ANOVA, and Jonkheere-Terpstra
test. Comparisons of gene expression among estrogenic
compounds were made by Wilcoxon-Mann–Whitney and
Jonkheere-Terpstra tests. Results of gene expression assays
are discussed in Section 2. Vaginal bleeding and early
parturition occurred in 1 of 8 dams in the high-dose group.
Bisphenol A treatment had no effect on maternal body
weight or number of live fetuses/litter, and there were no
gross or histopathological effects on ovary or uterus.
Prominent nipples and areolas were observed in males
and females in the high-dose bisphenol A group [number
of fetuses and litters affected were not reported].
Strengths/Weaknesses: Strengths are that these endpoints
appear appropriate; weaknesses are the limited
nature of the endpoints and the use of neat DMSO as
vehicle. The sample sizes are 4–5/endpoint/group and
judged to be inadequate. Of additional concern is the
route of administration.
Utility (Adequacy) for CERHR Evaluation Process:
This study is inadequate for the evaluation process.
Naciff et al. (2005), from The Procter and Gamble
Company, examined the effect of prenatal bisphenol A
exposure on male rat reproductive organ histology and
gene expression. Pregnant Sprague–Dawley rats were fed
Purina 5K96, a casein-based soy- and alfalfa-free diet.
Rats were housed in stainless steel cages before mating.
Rats were randomly assigned to groups (Z8 rats/group)
and s.c. injected with bisphenol A (B99% purity) in
DMSO at 0, 0.002, 0.02, 0.5, 50, or 400 mg/kg bw/day on
GD 11–20 (day of sperm detection 5 GD 0). Dams were
killed on GD 20, and testes and epididymides were
removed from fetuses. In 4 litters/dose group, 1 male
fetus/litter was examined for testicular histopathology.
In 5 litters/group, testes and epididymides from 5
littermates were pooled for a microarray analysis of
gene expression. Changes in gene expression were
further quantified using RT-PCR. Data were analyzed
by t-test, ANOVA, and Jonkheere-Terpstra test.
Birth Defects Research (Part B) 83:157–395, 2008
BISPHENOL A
245
Comparisons of gene expression among estrogenic
compounds were analyzed by Wilcoxon-Mann–Whitney
and Jonkheere-Terpstra tests.
Bisphenol A treatment had no effect on maternal body
weight or number of live fetuses/litter, and there were no
gross or histopathological effects on the testis or
epididymis. Prominent nipples/areolas were observed
in male and female fetuses from the high-dose group
[numbers of fetuses and litters affected were not
reported]. In pooled testis and epididymis samples from
the high-dose bisphenol A group, expression of 15 genes
was significantly altered in a dose-related manner. When
bisphenol A data were pooled with data obtained from
ethinyl estradiol and genistein and globally analyzed,
there were 50 genes that were significantly altered in the
same direction by all three compounds. The study
authors concluded that transplacental exposure to highdoses
of bisphenol A alters the expression of certain
genes in the testis and epididymis of fetal rats without
causing malformations in those organs. The study
authors noted that the dose response to bisphenol A
was monotonic with no evidence of robust quantifiable
responses at low doses.
Strengths/Weaknesses: Strengths are that these endpoints
appear appropriate; weaknesses are the limited
nature of the endpoints and the use of neat DMSO as
vehicle. The sample sizes are 4–5/endpoint/group and
judged to be inadequate. Of additional concern is the
route of administration.
Utility (Adequacy) for CERHR Evaluation Process:
This study is inadequate for the evaluation process.
Saito et al. (2003b), support not indicated, examined
the effect of prenatal bisphenol A exposure on testosterone
production during adulthood in rats. On GD 12–19
(day of vaginal plug not reported), 2 Wistar rats were s.c.
injected with the corn oil vehicle, 4 rats were s.c. injected
with 0.005 mg/day bisphenol A [purity not indicated],
and 2 rats were injected with 5 mg/day 17b-estradiol.
[Assuming a pregnant Wistar rat weights B0.33 kg,
0.005 mg/day would be equivalent to 0.015 mg/kg bw/
day bisphenol A.] Other materials found in dental
composites were also evaluated but will not be discussed.
During the lactation period, rats were housed in
polypropylene cages with synthetic bedding. [No information
was provided on feed.] Offspring were
housed separately at 3 weeks of age and killed at 13
weeks of age. Body and testis weights were measured in
all male offspring (22 in the bisphenol A group, 11 in the
vehicle control group, and 5 in the 17b-estradiol group).
Plasma testosterone level was measured by RIA, and
plasma cholesterol level was measured using a kit.
Activities of testicular enzymes involved in the production
of testosterone from progesterone were also examined
in an in vitro assay in which testicular microsomes
were incubated with 14 C-progesterone and 14 C-d 4 -androstenedione
for 20 min. Data were analyzed using
unspecified post-hoc tests. [Although not clear, it
appears that offspring were considered the statistical
unit for some analyses.]
Bisphenol A exposure had no effect on pup sex ratio.
No effects on body weight or absolute testicular weight
were observed in the bisphenol A group at 13 weeks of
age. However, relative (to body weight) testicular weight
was lower [by 6%] in rats of the bisphenol A compared to
the control group. Also observed in the bisphenol A