Paraboloid of axolotl retinal photoreceptor and bovine pituitary thyrotropin fraction share an antigen

Abstract

Lenses of newts (genera Notophthalmus, Triturus, Cynops) regenerate from irises in the presence of retinae of larval frogs (Rana) or adult salamanders (Hynobius, Ambystoma), species which are themselves incapable of lens regeneration from the iris. In newts, bovine pituitary thyrotropin preparation NIH-TSH-B8 can also stimulate lens regeneration from the iris. An antiserum against NIH-TSH-B7 (purified as is NIH-TSH-B8), absorbed with bovine lutropin preparation NIH-LH-B9, cross-reacts with bovine retinal glycoprotein extracts in immunodiffusion tests, and with retinal photoreceptor cells of the axolotl (Ambystoma mexicanum), as evidenced by immunofluorescence. In normal adult eyes and in eyes 21 days after lens removal, the paraboloid portion of the photoreceptor inner segments, and in some cases the perinuclear cytoplasm of the photoreceptor cells, contained the antigen. The cross-reacting antigen appears to be different from thyrotropin, and also different from the basic and acidic retinal fibroblast growth factors. However, immunodiffusion reveals a precipitation arc with retina-derived growth factor fraction III (EDGF III). If bovine pituitary thyrotropin preparations produce lens regeneration, and if these preparations cross-react with an antigen in the retinal photoreceptors, the retinal antigen may be involved in the stimulation of lens regeneration as well.