Responses of ram lambs to active immunization against testosterone and luteinizing hormone-releasing hormone

Publisher Website
Google Scholar
Abstract
Active immunization of young ram lambs against testosterone and LHRH blocked the growth attributes characteristic of intact ram lambs. Testosterone and LHRH-immunized lambs grew at a slower rate and converted feed to live weight gain less efficiently than albumin-immunized controls. Lambs immunized against testosterone and LHRH had high antibody titers for their respective antigens. Testosterone-immunized lambs had high serum concentrations of luteinizing hormone (LH) and testosterone, whereas LHRH-immunized lambs had low to nondetectable serum concentrations of these hormones. Release of LH and testosterone following the i.v. administration of LHRH (250 ng) was absent in LHRH-immunized lambs, but quantitatively similar for intact and albumin-immunized control lambs. Testosterone-immunized lambs responded as did conventional castrates with a large LH release, but testosterone concentrations were unchanged. These findings are discussed relative to the integrity of the hypothalamic-pituitary-testicular endocrine axis and the importance of gonadotropin support for normal testicular development. LHRH immunoneutralization effectively retards testicular development and produces a castration effect in young ram lambs.

This publication has 14 references indexed in Scilit: