Establishment of an ELISA system to measure pituitary hormones in teleosts.

We developed and validated a fluorescence-based competitive enzyme-linked immunosorbent assay (ELISA) for the parallel quantification of four key pituitary hormones-growth hormone (GH), prolactin (PRL), somatolactin alpha (SLα), and somatolactin beta (SLβ)-in grass carp (Ctenopharyngodon idella). The assay utilizes recombinant grass carp hormones as standards and corresponding rabbit polyclonal antibodies, with biotin-avidin-HRP amplification and HPPA-based fluorescence detection. Standard curves demonstrated high linearity and half-maximal inhibitory concentrations (ID50) ranging from 8.004 to 18.63 ng/mL. We successfully applied this ELISA to quantify hormone levels in plasma and culture medium from primary pituitary cell culture after stimulation with GHRH, SST, cortisol, and CRH, confirming its ability to detect physiologically relevant changes. This reliable, sensitive, and cost-effective ELISA provides a valuable tool for monitoring endocrine status in grass carp, with potential applications in growth performance assessment, reproductive management, and stress response studies in aquaculture. The method may also be adaptable to other cyprinid species due to high hormone sequence conservation.