Cytochrome P450 aromatase (CYP19) gene expression in ovarian granulose cells of hypothyroid rats induced by propylthiouracil

Abstract

Thyroid hormones are proven to have a direct effect on granulose cells, luteal cells and oocytes
due to their role in gonadotropin action on steroid hormone production. In vitro study showed
that tiroxine (T4) on granulose cells can stimulate ovarian steroidogenesis. Moreover, high
concentration of triiodothyronine (T3) increases the estradiol secretion and aromatase mRNA
expression. Hypothyroidism influences the cytochrome P450 aromatase (CYP19) gene expression.
The aim of this study was to evaluate the expression of the CYP19 gene in granulosa cells of
hypothyroid rats induced by propylthiouracil (PTU). This was quasi experimental study with
post-test only control group design. Eleven female Sprague-Dawley rats were divided into two
groups i.e. five rats as treated group that induced by PTU 0.1 g/L in aquadest for 30 days and
control group that not induced by PTU. Blood sample was taken and then T4 blood level was
measured using an enzyme-linked immunosorbent assay (ELISA). Whereas, CYP19 gene expression
in ovarian granulose cells was measured using immunohistochemistry. Unpaired t test was used
to compare the data obtained from treated and control groups. The results showed that T4
blood level on treated group (4.02 ± 0.39 ng/dL) was significantly lower than control group
(8.08 ± 1.63 ng/dL) (p = 0.000). However, CYP19 gene expression on treated group (30.84 ±
8.01%) was not significantly different compare to control group (25.06 ± 6.79%) (p = 0.227).
In conclusion, the CYP19 gene expression in ovarian granulose cells of rats is not change after
induction of PTU 0.1 g/L for 30 days, although the T4 blood level decreases.