THE IMMEDIATE EFFECT OF TSH ON RENAL IODIDE EXCRETION RATE IN RABBITS

Abstract

ABSTRACT The renal iodide excretion rate was determined in unrestrained female rabbits by means of conventional clearance technique or continuous monitoring of the whole body disappearance of iv injected 125I-iodide using an implanted Geiger-Müller detector. The immediate effect of pharmacological doses of bovine TSH was studied by both methods and a significant decrease in iodide excretion rate was recorded following the administration of a single TSH dose of 4 IU. The effect of TSH lasted 3–6 h. Injection of 10–20 μg TRH caused a transient delay in iodide disappearance (30–50 min) while 2–20 μg triiodothyronine iv or sc had no immediate effect on the iodide disappearance.