Synthesis, luteinizing hormone-releasing activity, and receptor binding of chicken hypothalamic luteinizing hormone-releasing hormone.

Chicken hypothalamic LHRH, which was recently structurally characterized, was synthesized by solid-phase methodology, characterized, and tested for LH-releasing activity using anterior pituitary cells from chickens and sheep, as well as for binding to chicken and rat anterior pituitary membrane receptors. Synthetic chicken LHRH exhibited identical properties to the isolated natural chicken LHRH in several chromatographic systems. Synthetic chicken LHRH displayed identical activity to natural chicken LHRH in stimulating LH release from dispersed chicken anterior pituitary cells, and synthetic mammalian LHRH was equipotent in this system. Both the natural and synthetic chicken peptides had similar low potency in stimulating LH release from cultured ovine anterior pituitary cells (approximately 1% of the potency of synthetic mammalian LHRH). The ED50 of binding to rat anterior pituitary membrane receptors was 2.5 X 10(-6) M for synthetic chicken LHRH, compared to 6.3 X 10(-8) M for synthetic mammalian LHRH.