Abstract: Immunological relationships among pituitary glycoproteic hormones and their subunits from fishes and mammals were studied with antisera (IS) raised in rabbits against carp gonadotropin (c-GTH), its α subunit (c-GTH α), and its β subunit (c-GTH β). Properties of the following preparations were compared: c-GTH and its subunits; gonadotropins (GTH) from two other Teleosts (indian catfish and eel), and a Chondrostean (sturgeon); and mammalian hormones (bovine LH and TSH, ovine FSH) and their subunits. In the α radioimmunoassays (RIAs) (IS c-GTH α, [125I]c-GTH α) or (IS c-GTH, [125I]c-GTH α) only the GTH from Cypriniform Teleosts (carp and indian catfish) cross-reacted: thus these α RIAs showed a high zoological specificity. However a weak immunological relatedness between c-GTH α and mammalian α subunits (b-LH α, b-TSH α, o-FSH α) could be shown in binding studies; in contrast, even at high concentration, the IS c-GTH α did not bind mammalian β subunits. The β RIA (IS c-GTH β, [125I]c-GTH β) exhibited a much weaker zoological specificity: not only all fish GTHs studied but also b-LH and b-LH β were able to compete with [125I]c-GTH β; furthermore, the degree of cross-reactivity (reflected by the slopes of the regressions) followed phylogenetic relationships. No cross-reaction was observed with the other mammalian preparations. The c-GTH RIA (IS c-GTH, [125I]c-GTH) showed an intermediate zoological specificity. Binding studies carried out with 125I-labeled mammalian preparations confirmed these data: b-LH and b-LH β were highly bound by IS c-GTH and IS c-GTH β whereas very low or no binding was observed with o-FSH or o-FSH β. A weak binding of b-TSH and b-TSH β by IS c-GTH and IS c-GTH β indicated a relationship between mammalian TSH β and TSH β or GTH β itself from the carp. Even at high concentration the IS c-GTH β did not bind mammalian α subunits. Thus the comparison of antigenic determinants gives additional evidence for homology among fish and mammal pituitary glycoproteins, indicating evolutionary relationship between the subunits of the same type (α or β). In the case of the β subunits, c-GTH β appears more closely related to mammalian LH β than to FSH β. Finally, due to the relative lack of immunological species specificity of the IS c-GTH β, the β RIA may be a useful tool to assay specifically GTHs from other species of fish.

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{{Explor lien
   |wiki=    Wicri/Eau
   |area=    EsturgeonV1
   |flux=    Main
   |étape=   Merge
   |type=    RBID
   |clé=     ISTEX:32C90A4AF4B2E62C3DA3CEC90FF131EA17BF6D36
   |texte=   Relations immunologiques entre les hormones glycoprotéiques hypophysaires de poissons et de Mammifères ainsi qu'entre leurs sous-unités α et β
}}