Urinary excretion of vitamin B12.

rfHE ANNOUNCE\-IENT of the discoveryof vitamin 1312 in 1948 byRickes, et a!.’ in this coumitry amid hi y Smith, et al.2 in Emiglamid imiitiat-e(! its use in various climiical entities. The principal use has been in the treatment of permiicious -anemia. The dosage of this drug has beemi more or less empirically established!. The hematologic amid subjective responses of the patient with permiicious anemia in relapse have been the main fact-om’s in det-ermimiimig dlosage re(luirements. Little is known aboutthe metabolism ofvitamin B12. The effective dosage as determined l)y it-s al)sorption, storage a-mid excretion pat-tem’mi has received relatively little attemition. Chow amid his (0-workers3 have shown that the intramuscular injection of 100 j g of vitamin B12 prod!uced detect-able B12 activity iii the urine of both permiicious anemia amid! nonpermiicious amiemia patiemits. Thus activity was fleeting, lasting approximately twelve hours. The oral admimiistration of 500 ag, on the other hand, resulted in no detectable B12 activity imi the urimie. Further expamisiomi of this work7 resulted in essentially the same results. Chest-emmami, Cuthbertsomi and Pegler4 foumid that t-he amountof vitamin Bm2 excreted imu the urine varied d!irectly with the amoumitgiven. They diefined the relatiomuship betw-eemi the amount givemi amid the amoumit imijectedl by the formula: E = D 1.2D#{176}89,where E is the amoumit of vitamimi B12 excreted after eight hours amid D is the amoumit of vitamin B12 injected intramuscularly. Itis the purpose of this paper to present the urinary excret-iomi pattermi of vitamin B12 imi patients who have been given varying amount-s of vitamin B12 imitramuscularly.