Abstract
An investigation was carried out to determine the tissue of origin of serum alkaline phosphatase in normal dogs and in dogs treated with the insecticide dieldrin. The work involved comparisons between tissue and serum alkaline phosphatases on the basis of immunological and electrophoretic properties. Alkaline phosphatases from dog liver, kidney, intestine and bone were separable by electrophoretic pattern on polyacrylamide gel, except for some overlapping between bone and renal bands. By electrophoretic analysis, liver appeared to be the major source of serum alkaline phosphatase in both normal and hyperphosphatasemic sera from dieldrin treated dogs. Rabbit antiserum to dog intestinal alkaline phosphatase was used to demonstrate phosphatase of intestinal origin in some dog sera. The presence of this additional serum enzyme was not related to administration of dieldrin. The work was extended to an investigation of the origin of alkaline phosphatase in dog urine. Urinary phosphatase differed electrophoretically and immunologically from that of the kidney and showed some similarity to bladder alkaline phosphatase. Alkaline phosphatase from dog intestinal mucosa was shown to differ from phosphatases extractable from the predominant bacterial flora of dog duodenum and faeces. Immunofluorescence was used to demonstrate alkaline phosphatase on the outer surface of intestinal villi.