Bioeffective monoclonal antibody at gonadotropin-releasing hormone: R

A monoclonal antibody generated against the decapeptide gonadotropin-releasing hormone (GnRH) was effective in intercepting the bioactivity of the hormone; it blocked ovulation in rats. The antibody reacted optimally with the native hormone. Substitution of amide at the COOH termi- nus by a carboxyl group decreased immunoreactivity by a fac- tor of 200. The antibody recognized the amino acid sequences 4-6, 7-10, and 4-10 to a variable degree, which suggests that the epitope has a conformation involving the entire molecule, with the NH2- and COOH-termninal regions probably in prox- imity. The antibody was also competent to suppress the pro- gression of estrus in dogs, an indication that GnRH may play an inductive role in the reproductive function of dogs.