Digoxin-like immunoreactivity: occurrence in three molecular forms and partial characterization.

Digoxin-like immunoreactivity (DLI) has been found in serum from subjects with a variety of physiological and pathological conditions, including uremia, liver disease, pregnancy, and the neonatal period. The physicochemical nature of this material is still not known. Using gel filtration chromatography, extraction with methylene chloride, and treatment with beta-glucuronidase, we determined that serum DLI exists in three forms: protein-bound, glucuronidated, and free, with respective mol wt of 5000, 400, and 230. In serum, DLI exists in the protein-bound and free forms, while in urine, DLI is found in the glucuronidated and free states.