Male and Female Brains in a Test Tube 133expression levels of RORA and CYP19A1 (aromatase) gene expressions in cells
exposed to 1.2 nM/l concentration of testosterone in vitro. The cell lines from
one male and one female origin were exposed to 0.64 nM/l (representing nor-
motypic), 0.82 nM/l (representing classical autism), and 1.2 nM/l (representing
Asperger syndrome) as described by Baron‐Cohen et al. [3]. The studies were
designed according to large retrospective studies where the elevated testoster-
one levels were seen by Baron‐Cohen’s group in amniotic fluids [3]. We exposed
these NBCs for 5 days and evaluated for various parameters by histological and
immunological means including central chromatolysis, axonal morphometric
analyses, syncytia formation, and axonal changes as well as changes in size,
shape and relative diameter measurements, as described by us recently [3].
We also analyzed these cell lines for degree and percentage of neurons positive
for oxytocin receptor by immunological means [2]. First, we compared the
effects of testosterone at normotypic versus autism levels and normotypic versus
Asperger syndrome levels. In addition, we determined all three different levels
of testosterone in both male and female NBCs and whether these testosterone
levels had differential neuromodifications on male versus female NBCs,
particularly with regards to oxytocin‐receptor positive neurons.
Effects of Three Different Levels of Testosterone
on Neuronal Morphology
As shown in Figure 5.1, significant morphological neuromodifications were
observed in neurons of both male and female NBCs. Exposure to 0.64 nM/l
(representing normotypic) and 0.82 nM/l (representing autism) of testosterone
led to significant morphologic changes as measured by central chromatolysis,
enlargement of the neuronal cell body, shortening or abnormal increase of
axonal length, change in cellular diameter, and syncytia formation. Similarly,
exposure to 0.64 nM/l and 1.2 nM/l (representing Asperger syndrome) also
induced significant changes in NBCs exposed to higher levels of testosterone.
The most profound changes were increased neuronal length and thinning of
axons in both 0.82 and 1.2 nM/l testosterone exposures compared with 0.64
nM/l, representing the normotypic level [3–6]. We also compared the morpho-
logical characteristics in testosterone unexposed control cell lines from both
genders and determined that exposure to low levels of testosterone in cell lines
from both genders induces significant morphological changes.
One of the most agreed upon concepts in ASD is that it is associated with
modifications in brain connectivity, even though the nature and extent of
these neuromodifications remain controversial. Early analyses of connectivity
derived from functional magnetic resonance imaging (fMRI) from various
brain regions reported weaker functional connectivity between brain regions
in individuals with ASD, leading to the long‐distance cortical “under‐
connectivity” theory [67,70–77]. Recent evidence utilizing fMRI suggest