Corticotrophin-releasing factor-like immunoreactivity in human 24 h urine

This report is the first demonstration of the presence of corticotrophin-releasing factor-like immunoreactive material (CRF-LI) in human urine. Our studies, using immunoaffinity chromatography for extraction, followed by reverse phase high performance liquid chromatography for further purification, and radioimmunoassay for final peptide measurement, suggest that CRF-LI from human urine is similar, if not identical, to human CRF. Urinary CRF-LI excretion in normal subjects was 1.48 +/- 0.69 ng/24 h (mean +/- SD; n = 20) with no significant differences between the sexes. During pregnancy, urinary CRF-LI excretion increased, and a significant correlation between urinary CRF-LI excretion and the gestational age was seen (r = 0.62; P less than 0.0001). We suggest that urinary 24-h CRF-LI excretion may reflect the secretion of CRF into the circulation. Measurements of CRF-LI in the urine may have several advantages over determinations of hormone levels in plasma.