A DETERMINATION OF THE RATE OF THYROID HORMONE SECRETION AT VARIOUS ENVIRONMENTAL TEMPERATURES¹

The influence of food intake and ambient temperature on the rate of thyroxine utilization.

“…(Dempsey & Astwood, 1943;Stevens et al 1955;Brown-Grant, 1956;Freinkel & Lewis, 1957;Reichlin, 1966;D'Angelo, 1960;Heroux & Brauer, 1965). Under these conditions, the voluntary increase in food intake on exposure to cold would occur, and the initial stimulus to the thyroid gland supplied by the fall in ambient temperature would be sustained by the additional food.…”

“…The role ofthe thyroid gland in the response of a homoiotherm to a change in ambient temperature has been reported many times (Dempsey & Astwood, 1943; Stevens, D'Angelo, Paschkis, Cantarow & Sunderman, 1955;Brown-Grant, 1956;Gregerman & Crowler, 1963;Reichlin, 1966). When there is a fall in ambient temperature, the rate of secretion and utilization of hormone increases, and there is an associated increase in the resting metabolic rate.…”

The effect of lowered environmental temperature on the peripheral metabolism of labelled thyroxine in the sheep

“…To date, the evidence for an enhanced peripheral degradation of thyroid hormone in the cold is convincing, although indirect. It rests upon the observation that at low temperatures hypophysectomized animals and animals rendered athyroidal by chemical or surgical means require greater replacement dosages of thyroid hormone (Stevens et al 1955;Dempsey & Astwood, 1943;Rand, Riggs & Talbot, 1952;Kassenaar, Lameyer & Querido, 1956;Bondy & Hagewood, 1952).…”

The Use of Radioiodine in Physiological and Clinical Studies on the Thyroid Gland

“…Many other factors undoubtedly influence the level of activity of the gland, including the dietary iodine intake and environmental temperature. Leblond et al (51) found that rats exposed to an environment at 00 C. have a higher radioiodine uptake than rats at 22°to 260 C. (control T0), and by the goiter-prevention method (111), it can be shown that a greater amount of administered thyroxine is required in a cold, than in a warm environment.…”