Molecular characterization of gonadotropin subunits and gonadotropin receptors in black porgy, Acanthopagrus schlegeli: Effects of estradiol-17β on mRNA expression profiles

The cDNAs of three gonadotropin (GTH) subunits (GTHα, FSHβ, and LHβ) and two GTH receptors (FSHR and LHR) from pituitary and gonads of black porgy were cloned. The nucleotide sequences of the GTHα, FSHβ, and LHβ cDNA were 354, 363, and 414 base pairs (bps) in length with open reading frames (ORF) encoding peptides of 117, 120, and 137 amino acids, respectively. The FSHR and LHR cDNA was 2118 and 2076 bps in length with ORFs encoding peptides of 705 and 691 amino acids, respectively. To study the mechanism of the estradiol-17β (E2) action, we examined the expression pattern of GTH subunit mRNAs in pituitary and GTH-receptor mRNAs in gonads, and the changes of plasma E2 level when E2 treatment was applied to immature black porgy. E2 treatment increased mRNA expression levels of the genes and plasma E2 levels, indicating that E2 stimulated the increases in GTH subunit and GTH-receptor mRNAs. These data indicate that E2 plays an important regulatory role in the brain–pituitary–gonad axis of immature black porgy. We provide the molecular characterization and expression of the GTH subunits and GTH receptors during sex change in the protandrous black porgy.