“Nitrogenous Compounds Immobilized In An Aged Rat”, 1970-02 (; similar):
A pregnant rat received 8 mc of tritiated tyrosine at the time of giving birth (from 7 days before, to 6 days after).
No radioisotopes were ever given directly to the litter born.
A male from this litter died from pneumonia at age 809 days.
After removal of water and acetone solubles and of phospholipids, hydrolysis of the residue released the following radioactive amino acids, parts of molecules fixed until death and containing tritium present at birth: lysine, arginine, aspartic acid, glutamic acid, serine, listed in order of decreasing radioactivity, with lysine carrying 29% of the total tritium present.