Effect of food deprivation and altered thyroid status on the hypothalamic-pituitary-thyroid axis in the rat.

摘要: Propylthiouracil (PTU) was administered to rats for different lengths of time with or without food deprivation on the last 2 days. Within 4 days PTU treatment peripheral 3,5,3'-tri-iodothyronine (T3) fell low levels and beta-subunit thyroid-stimulating hormone (beta-TSH) mRNA increased significantly in anterior pituitary. Pro-thyrotrophin-releasing (pro-TRH) hypothalamic paraventricular nucleus (PVN) control group animals by 8 food-deprived day 12; increment pro-TRH 12 less than that group. In a second study, were treated intraperitoneal injections T3 deprivation. After treatment, markedly PVN beta-TSH pituitary reduced. Food had no additional suppressive effect. These studies confirm predominant effect thyroid axis is at suprahypothalamic level it can, least part, overcome increase TRH due diminished feedback.