Estradiol-17β regulates the expression of insulin-like growth factors 1 and 2 via estradiol receptors in spotted scat (Scatophagus argus).

Insulin-like growth factors (Igf1 and Igf2) play a key role in growth and development of vertebrates. In mammals, the expression of IGF s is regulated by estradiol-17β (E 2) via estrogen receptors (ESRs). The expression of igf s can also be regulated by E 2 in fish, while comparative study of this is still lacking. The present study examined tissue distribution of igfs and hepatic expression of igf s and esr s during gonad development in Scatophagus argus by real-time PCR. Serum E 2 concentration was measured by enzyme-linked immunosorbent assay (ELISA). The hepatic expression of igf s and esr s at gonadal phase III, incubated with either E 2 (0.1, 1 or 10 μM) alone or in combination with estrogen receptor antagonists-fulvestrant, MPP or PHTPP, was measured. igf1 and igf2 expressed highest in liver of both sexes. Igf1 , esr1 and esr2b expressions and serum E 2 concentration increased, while igf2 and esr2a expressions decreased, during ovary development. Igf s and esr s expressions increased while serum E 2 concentration maintained low during testis development. In females, E 2 incubation enhanced the expressions of igf1 and esr1 but inhibited that of igf2 and esr2a. Both fulvestrant and MPP inhibited up-regulation effect of E 2 on igf1 and esr1. Fulvestrant enhanced down-regulation effect of E 2 on igf2 and esr2a , but MPP conversely. In males, E 2 incubation enhanced the expressions of igf s, esr1 and esr2a. Fulvestrant and MPP inhibited up-regulation effect of E 2 on igf s and esr1. PHTPP inhibited igf1 and esr2 expressions in both sexes. Our results indicated that the expression of igfs is regulated by E 2 via Esrs in S. argus. Unlabelled Image • igf1 and igf2 was found to be expressed highest in the liver of both sexes in S. argus. • There is a correlation between the expression of igf s, esr s and serum E 2 concentration in S. argus. • It was first found in fish that E 2 regulates the expression of igf s via Esrs. • E 2 regualates the expression of igf1 via both Esr1 and Esr2 in female and male S. argus. • E 2 regualates the expression of igf2 via Esr2a and Esr1 in female and male S. argus , respectively. [ABSTRACT FROM AUTHOR]