Endorphinergic modulation of immune function: potent action of the dipeptide glycyl-L-glutamine.
Glycyl-L-glutamine (GLG), the carboxy terminal dipeptide of B-endorphin, inhibits brainstem neuronal activity. It also occurs along with B-endorphin in pituitary secretory vesicles suggesting a neurosecretory role for this dipeptide. We have evaluated potential immunoregulatory actions of this compound using the Phytohemaglutinin (PHA) blastogenesis and the concanavalin A (ConA) suppressor cell induction assays. GLG in low doses (10(-12) M) enhanced the response of human lymphocytes to PHA induced blastogenesis, however; with higher doses of the dipeptide (10(-7) M) immunosuppression was consistently observed. In the suppressor cell induction assay, when GLG was used together with ConA, we observed a dose-dependent inhibition of suppressor activity. These results clearly indicate that GLG produces a dose dependent bidirectional modulation of at least two indicies of immune function, and confirm the presence of a second pituitary peptide with the potential for potent immunomodulatory action.
D003208:Concanavalin A / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004723:Endorphins / Q000502:physiology*; D006801:Humans; D007109:Immunity / Q000187:drug effects*; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D010835:Phytohemagglutinins / Q000494:pharmacology; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000502:physiology; D001615:beta-Endorphin
D004151:Dipeptides; D004723:Endorphins; D010835:Phytohemagglutinins; D003208:Concanavalin A; C039788:glycylglutamine; D001615:beta-Endorphin