Biologic Decay Periods of Chloride in Man with Use of Long-Life Cl 36 as Tracer. ∗

Abstract

From the data obtained in tracer studies with radiochloride,† Cl³⁶ (t_.5 2 × 10⁶ yrs.), it was possible to estimate the biologic decay periods of this element for human subjects. A knowledge of the biologic decay rates of chloride in man is of importance in the understanding of the physiologic turnover and exchange rates in normal subjects, in patients with edematous states, including congestive heart failure, and in individuals internally contaminated as a result of military and peaceful applications of nuclear energy. From previous investigations with Na²² in man and Cl³⁶ in dogs, estimations of biologic decay rates of chloride in normal man with relatively constant compartment size were made ( 2 - 5 ). The observed biologic decay rates agree with the estimated values.

Cl³⁶ (10,000,000 CPM or approximately 50 μC) as NaCl in water was administered intravenously to 3 female subjects: Subject No. 501, 31 years old with previous hyperthyroidism controlled with propylthiouracil; Subject No. 502, 62 years old with arteriosclerosis, essential hypertension, mild diabetes and mild congestive heart failure, who was made to compensate or allowed to decompensate, as desired, during the course of the study; Subject No. 503, 59 years old with hypertensive and arteriosclerotic heart disease with severe congestive heart failure, who died during the thirty-seventh day of study. The other 2 subjects were studied for 70 continuous days.

Blood was collected once daily under oil and immediately centrifuged; the serum was assayed as described previously ( 1 , 3 , 5 ). Urine and stools were collected as excreted and were also assayed. Any vomitus or other fluids removed, such as ascitic or pleural fluid, were likewise studied in order to determine the total elimination of Cl³⁶ from the body.

The mean biologic decay periods for the entire study for each subject are presented in Table I.