Effect of thyrotropin on fractional blood flow of chick thyroid gland

¹ Department of Medicine, University of California Medical Center, Los Angeles, California

The effect of thyrotropin (TSH) on the blood flow of the chick thyroid has been estimated by the distribution of Rb⁸⁶. Mean thyroidal blood flow estimated from the 30-sec Rb⁸⁶ uptake was 4.60% of cardiac output/g of tissue. During the 1st hr after the intracardiac administration of TSH, there was no effect on the thyroidal blood flow fraction; at 2 hr there was a significant response; by 4 hr the blood flow fraction had doubled. The response then gradually ebbed and disappeared by 24 hr. The long latency of the hyperemic response to TSH is interpreted as indicating that hyperemia is secondary to earlier metabolic activation. Of the various consequences of TSH action, only those with similarly long latencies, such as enhancement of iodide uptake, could possibly be dependent on the hyperemia. The thyroidal blood flow fraction remained constant during growth from 1.5 to 30 days of age, while the relative thyroid weight declined sharply. TSH produced its characteristic effect at all ages studied.

This article has been cited by other articles:

				M. Iitaka, S. Miura, K. Yamanaka, S. Kawasaki, S. Kitahama, Y. Kawakami, S. Kakinuma, I. Oosuga, S. Wada, and S. Katayama Increased Serum Vascular Endothelial Growth Factor Levels and Intrathyroidal Vascular Area in Patients with Graves' Disease and Hashimoto's Thyroiditis J. Clin. Endocrinol. Metab., November 1, 1998; 83(11): 3908 - 3912. [Abstract] [Full Text]