Psychosomatic Medicine 30:682-695 (1968)
© 1968 American Psychosomatic Society

Thyroid (Plasma Butanol-Extractable Iodine) Responses to 72-Hr. Avoidance Sessions in the Monkey

¹ Departments of Neuroendocrinology and Experimental Psychology, Walter Reed Army Institute of Research, Walter Reed Army Medical Center, Washington, D. C.

Plasma thyroid hormone levels, as judged by the BEI measurement, show slow but prolonged elevations in association with conditioned avoidance sessions in the monkey.

The peak of the mean BEI response occurs at the end of the 3-day avoidance session and represents about a 50% elevation above baseline values. Levels remained elevated well into the recovery period and the response was prolonged as much as 2 or 3 weeks in some experiments.

Smaller, but significant, BEI elevations occurred during the first 24 hr., being observed in 14 of 16 experiments.

It is suggested that plasma thyroid hormone levels are relatively "tightly regulated" and that special consideration should be given to the unique dynamic features of this system in the evaluation of experimental results.

The thyroid response did not appear to represent maximal thyroid secretion, and no evidence of thyroid exhaustion was observed.

Some decrease in duration of BEI response with repetition of avoidance sessions and some differences in mean BEI response between different monkeys were observed.

The relationship of the present findings to previous conflicting findings in this field is discussed.