THE CHARACTERIZATION OF GROWTH HORMONE RELEASE INHIBITING HORMONE-LIKE IMMUNOREACTIVITY IN NORMAL URINE

Abstract

Using a previously described radioimmunoassay for growth hormone release inhibiting hormone (GH-RIH), the presence of GH-RIH-like immunoreactivity in [human] urine was characterized by demonstrating mobility identical to synthetic GH-RIH standard on 2 sephadex gel chromatographic systems, and parallelism of dilutions of the sephadex fractions with synthetic GH-RIH. Furthermore, 74% of the sephadex fraction cross-reacting in the immunoassay bound to antibody conjugated to sepharose and could be eluted by 1 M acetic acid. This immunospecific eluate showed identity with synthetic RH-RIH on both ion exchange and TLC. GH-RIH-like immunoreactivity is present in normal urine; this may have potential relevance in the search for a physiological role for this peptide.