Presence of growth hormone-releasing factor-like immunoreactivity in human cerebrospinal fluid

Immunoreactive human growth hormone-releasing factor (I-hGRF) in human cerebrospinal fluid (CSF) was measured by radioimmunoassay using antiserum specific to the C-terminal portion of hGRF(1-44)NH2. Dilution curves of I-hGRF in the CSF were completely parallel to that of synthetic hGRF(1-44)NH2 standard. On Sephadex G-50 column chromatography a single peak of I-hGRF in the CSF was eluted at the position of synthetic hGRF(1-44)NH2. I-hGRF was present in the CSF of all control patients without any endocrine disease (mean +/- SE, 29.3 +/- 2.0 pg/ml) whereas I-hGRF in the CSF was not detectable (less than 5.8 pg/ml) in any of the patients with hypothalamic germinoma. In all patients with idiopathic GH deficiency, I-hGRF in the CSF was measurable but its concentration (15.1 +/- 1.0 pg/ml) was significantly (p less than 0.05) lower than that in the control subjects. No difference in I-hGRF levels of the CSF was observed between patients with acromegaly and control subjects. These findings demonstrate for the first time that I-hGRF is present in human CSF. Measurement of I-hGRF in the CSF may be useful for understanding the pathophysiology of hypothalamo-pituitary diseases.