[Distribution of oligonucleotide derivatives and their stability in murine tissues]

Distribution and stability of benzyl-[5'-32P] phosphoramides of oligonucleotides and their phosphorothioate analogs were investigated. Oligonucleotide derivatives are distributed among all murine organs, the maximal concentration being observed in the liver and kidney, and minimal in the brain. Intravenous and intraperitoneal injections resulted in a faster distribution of oligonucleotides among the tissues than subcutaneous injections. Hydrolysis rate varied from tissue to tissue, and in 30 min after injection 5 to 50% of intact oligonucleotides were found. Hydrolysis did not depend on the injected dose in the range of 0.15-150 nmol per mouse. The 3'-terminal cholesterol groups protected the oligonucleotides considerably. In the blood stream and pancreas phosphorothioate oligonucleotides showed much higher stability than their phosphodiester counterparts. A protein interacting specifically with the oligonucleotides was discovered in the liver, kidney and pancreas.