Marilyn H. Williams

Metabolism of the Lanthanons in the Rat.

Summary 1. The metabolism of the lanthanons has been studied in the rat on a systematic basis using tracer technics. High-specific activity preparations were administered orally or intramuscularly as citrate complexes. 2. Data are presented for the fifteen lanthanons 1 and 4 days after administration and at intervals up to 8 months for those isotopes with sufficiently long half lives. In general, absorption from the parenteral injection site was relatively complete at four days. Gastrointestinal absorption of the 4 lanthanons administered orally was insignificant. 3. The light lanthanons (lanthanum through samarium). Deposition was primarily in the liver and skeleton, 50 and 25% of the administered dose respectively. Elimination from the liver (presumably by way of the bile duct to the gastrointestinal tract) was quite rapid with a half-time of about 15 days. Two months after injection the skeleton retained about two-thirds of its initial deposition; there was no further elimination from the skeleton during the subsequent 8 months. 4. The transition lanthanons (europium and gadolinium). Deposition was more nearly equal in liver and skeleton, 30 and 40% of the administered dose respectively. Excretion was both fecal and urinary. 5. The heavy lanthanons (terbium through lutetium). Deposition was mainly skeletal, 50 to 65% of the administered dose. Elimination from the skeleton was slow with a half-time of approximately 2.5 years. Excretion of extra-skeletal heavy lanthanon occurred within the first two weeks after injection and was almost entirely urinary.

The induction of tumors in the rat by astatine-211.

Exposure of rats to sublethal amounts of At/sup 211/ results in the early appearance of large numbers of mammary tumors, many of them malignant, and in the production of an altered functional state simulating menopause. It is evident that the tumor induction is not yet tested for its association with radiation exposure separately from the endocrine disturbance. (auth)

Survival of hibernating ground squirrels (Citellus tridecemlineatus) after single and fractionated doses of cobalt-60 gamma radiation.

The effects of hibernation on survival after irradiation was studied in thirteen-lined ground squirrels (Citellus tridecemlineatus). The

THE METABOLSIM AND TOXICITY OF RADIUM-223 IN RATS

{\rm LD}_{50(90)}

Development of Spontaneous Mammary Tumors over the Life-Span of the Female Charles River (Sprague-Dawley) Rat: The Influence of Ovariectomy, Thyroidectomy, and Adrenalectomy-Ovariectomy

for a single dose of60 Co gamma radiatio...

Construction of a Growth Curve for Mammary Tumors of the Rat

UCRL 8189 UNIVERSITY OF CALIFORNIA THE METABOLISM AND TOXICITY RADIUM-223 IN RATS OF TWO- WEEK LOAN COpy ,Ii This is a library Circulating Copy which may be borrowed for two weeks. For a personal retention copy, call Tech. Info. Diuision, Ext. 5545