Characterization of hepatic sexual dimorphism in Alb-DsRed2 transgenic rats

We previously created the Alb-DsRed2 transgenic (Tg) rat that specifically expresses the red fluorescent protein, DsRed2, in the liver. Herein, we demonstrate that the DsRed2 expression is sexually dimorphic and exhibits a male-specific pattern. The profiling of sexual dimorphism in DsRed2 expression during pre-pubertal development was investigated using an in vivo fluorescent imaging analysis. The DsRed2 expression decreased gradually in both sexes until 28days after birth. While DsRed2 expression was not persistent in the female liver, the male hepatic expression increased again at 35days. Sexual dimorphic DsRed2 expression did not change in gonadectomized male and female Tg-rats. However, female hepatic DsRed2 was induced 72h after the hypophysectomy. Hepatocytes isolated from the female Tg-rats also revealed DsRed2 induction by 96h in culture. These results suggest that the pituitary hormone suppresses the female hepatic DsRed2 expression causing the sexual dimorphism of DsRed2 expression.