K. Miyashita et al., REGULATION OF RAT-LIVER TYPE-1 IODOTHYRONINE DEIODINASE MESSENGER-RNALEVELS BY TESTOSTERONE, Molecular and cellular endocrinology, 115(2), 1995, pp. 161-167
To investigate the underlying mechanisms of sex-related differences in
liver type 1 iodothyronine deiodinase (ID1), we studied the sex-relat
ed differences and roles of sex steroids in liver ID1 mRNA levels in t
he rat. In both euthyroid and thyroidectomized rats, liver ID1 activit
y and ID1 mRNA levels in female rats were less than those in male rats
. A positive correlation was observed between liver ID1 activity and I
D1 mRNA levels. Liver ID1 activity and ID1 mRNA levels in male rats de
creased after orchiectomy, and were increased to control levels by tes
tosterone administration. Ovariectomy or beta-estradiol administration
did not alter liver ID1 activity or ID1 mRNA levels in female rats. I
D1 mRNA levels in cultured rat hepatocytes were significantly increase
d by testosterone, but not by beta-estradiol. These results suggest th
at the sex-related differences in liver ID1 activity are attributable
to differences in ID1 mRNA levels, and that testosterone plays an impo
rtant role in the sex-related differences in liver ID1 mRNA levels.