MATERIALS AND METHODS constructed stalls which Six lactating goats were maintained in specially Three of these goats allowed for the separate collection of urine and feces. ), and the other animal per uCi (200 -243 received acute oral doses of curium uCi per animal. three goats received intravenous curium-243 doses of 20.8 during this used s animal the n on matio infor l Table 1 provides some genera average pre-study an had and age, of years 3 and 1 en The goats were betwe study. wCi/kg weight of 43.5 kg. Oral and intravenous doses were approximately 4.7 for made s were tment adjus dose no noted, as , and 0.47 uCi/kg, respectively but Composite daily collections of milk, individual variations in animal weight. over a 144-hour period after goat each d urine, and feces were sample from this period. during taken also s Blood sample were dosing. Urine was collected with in-dwelling inflatable catheters which drained into The goats were milked by hand twice daily, and milk polyethylene bottles. All urine, milk, and from AM and PM milkings was mixed in plastic bottles. were then taken from aliquots weighed Three weighed. fecal collections were the respective composites and placed in individual aluminum cans with formaide- Addition of formaldehyde prior to mixing the hyde added as preservative. s due to the pellet nature of goat feces. advantageou was fecal collections venipuncture, were centrifuged and the jugular by collected samples, Blood The packed cells were pipette. disposable a using separated cells plasma and plasma and cells were of Samples al saline. physiologic with times two washed e was then added as a Formaldehyd water. distilled with y diluted individuall preservative and the sample containers were sealed. The animals were sacrificed using intravenously administered euthanasia solution approximately 162 hours post-treatment. Sacrifice collections included samples of bone, liver, kidney, gall bladder, bile, lung, gonads, spleen, muscle, lymph nodes, heart, thymus, adrenals, gastrointestinal tract, and mammary gland. Ten ml of formaldehyde was added to each tissue sample before the samples were individually sealed in aluminum cans. At time of sacrifice, total weights were taken on most organs so that the percentage of administered dose retained by a specific tissue or organ could be calculated. This obviously was not practical in the case of some tissues, e.g., muscle, bone, etc. Under these conditions, total curium content was based on calculated organ weights using the respective percentage of body weight reported by Davis et al. (1975). Curium concentrations from the femur (diaphysis and epiphysis) and sternum were averaged to estimate the osseous retention values. The curium-243 stock material was obtained as a nitrate salt from Oak Ridge National Laboratory, and contained curium-244 as a major impurity (55.9 atom % curium-243, 42.1 atom % curium-244). Intravenous doses, approximately 5 ml in volume and buffered to a pH of 6 with citrate (0.15 M NaCl--0.05 M sodium citrate--0.0025 M citric acid), were administered by jugular venipuncture. The oral doses (in 100 ul of 0.6 M HCl) were placed in gelatin capsules containing cellulose fiber and administered using a balling gun. 169