Altered GnIH precursor gene expression during early development of Nile tilapia, Oreochromis niloticus

Abstract

ABSTRACT This study investigated the expression patterns and relationships among gonadotropin inhibiting hormone (GnIH), gonadotropin releasing hormone (GnRH), luteinizing hormone (LH), and follicle stimulating hormone (FSH) mRNA during early developmental phases of Nile tilapia. GnIH mRNA could be detected immediately after hatching and was maintained until 11 weeks post-hatching (wph), at which time presumptive puberty occurs in this species. Subsequently, levels remained low for up to 24 wph. GnIH expression was relatively high until the onset puberty, and started to decrease when the expression of GnRH1, LH-β, and FSH-β mRNA increased. Expression of GnRH1 was low until 11 wph, but increased significantly at 12 wph. Markedly high of expression occurred at 12 and 24 wph. Results from this study suggest that GnIH is involved in the inhibition of sexual maturation during early development periods until the onset of puberty in this species.