Radioimmunoassay of MIF-1/Tyr-MIF-1-like material in rat pineal.
The hypothalamic peptide MIF-1 (Pro-Leu-Gly-NH2) was coupled to thyroglobulin and injected into rabbits. The resulting antiserum reacted with the tetrapeptide Tyr-MIF-1 to a greater extent than with the tripeptide MIF-1, presumably because of a better conformation for antibody binding. By radioimmunoassay (RIA), immunoreactive MIF-1/Tyr-MIF-1-like material was found in the pineal gland of each of the 100 rats examined. The tendencies for slightly higher levels in pineals obtained from rats kept in constant darkness for two weeks, from rats in a normal light cycle decapitated at noon, or from rats which had been hypophysectomized were not statistically significant. Gel filtration of pineal extracts on a column of Sephadex G-10 revealed that by RIA one immunoreactive peak eluted near MIF-1 and oxytocin, and another peak near Tyr-MIF-1. The results suggest the presence in pineal tissue of an MIF-1-like material as well as a novel peptide containing Tyr-Pro-Leu-Gly-NH2 or a closely related structure for which oxytocin is unlikely to be the precursor.
D000818:Animals; D002850:Chromatography, Gel; D002940:Circadian Rhythm; D003624:Darkness; D009075:MSH Release-Inhibiting Hormone / Q000032:analysis* / Q000276:immunology; D008297:Male; D010121:Oxytocin / Q000378:metabolism; D010870:Pineal Gland / Q000032:analysis*; D011863:Radioimmunoassay; D051381:Rats; D013954:Thyroglobulin
D010121:Oxytocin; D013954:Thyroglobulin; D009075:MSH Release-Inhibiting Hormone