Iopanoic acid has been shown to block thyroxine (T4)-5'-monodeiodination in rat anterior pituitary in vitro. To test the hypothesis that the acute decrease in thyrotropin (TSH) after infusion of T4 into hypothyroid rats requires intrapituitary T4 to 3,5,3'-triiodothyroxine (T3) conversion, the effect of iopanoic acid treatment on the generation of nuclear T3 from intrapituitary conversion and t...

0.1 ,uM triiodothyronine (T3) (1981. Endocrinology. 108: 2397). The current study characterizes that enhanced accumulation. Confluent cultures were maintained in thyroid hormnone-deficient media without or with added T3, labeled with [3H]acetate and analyzed for total [3H]GAG and [3H]hyaluronic acid content. Addition of T3 to thyroid hormone-depleted media consistently inhibited the incorporati...

Although triiodothyronine (T3) is widely used clinically, preclinical support for its antidepressant-like effects is limited, and the mechanisms are unknown. We evaluated 1) the antidepressant-like effects of T3 in the novelty suppressed feeding test (NSFT), tail suspension test (TST), and forced swim test (FST), 2) the role of presynaptic 5-HT(1A) receptors in the antidepressant-like mechanism...

We have investigated the effect of triiodothyronine (T3) on the transformation of normal rat kidney (NRK) cells by the Kirsten strain of murine sarcoma virus (Ki-MSV). When NRK cells were grown and infected with Ki-MSV in medium lacking T3, the yield of transformed foci was about one-half that observed in the cultures supplemented with T3. Individual foci appeared some what later in cells grown...

We have recently reported that the entry of 3,3',5-triiodo-L-thyronine (T3) into mouse 3T3 fibroblasts occurs by receptor-mediated endocytosis (Cheng, S. Y., Maxfield, F. R., Robbins, J., Willingham, M. C., and Pastan, I. (1980) Proc. Natl. Acad. Sci. U. S. A. 77: 3425-3429). In this communication, we evaluated the functional significance of this mode of entry using GH3 cells, a growth hormone-...

OBJECTIVES The low triiodothyronine (T3) syndrome indicates poor prognosis for patients with cerebral infarction. It is unknown, however, whether basic conditions or severities in the patients with the low T3 syndrome are different compared to those without the low T3 syndrome. METHODS We compared the risk factors and the severity of the disease using the National Institutes of Health stroke ...

The in vivo growth hormone (GH) response of immature domestic fowl to thyrotrophin-releasing hormone (TRH) and GH-releasing factor (GRF) was suppressed in birds fed diets supplemented (1 ppm) with triiodothyronine (T3) or given bolus intraperitoneal (ip) injections (100 micrograms/kg for 10 d) of T3. Supplementation (ppm) of the diet with T4 had no effect on secretagogue- induced GH release. Ex...

The expression of NADPH cytochrome P450 oxidoreductase (P450R) in rat liver is positively regulated by thyroid hormone (T3), at both the transcriptional and post-transcriptional levels. Here we investigate the effects of T3-induced hyperthyroidism on the regulation of P450R protein synthesis. T3 treatment of adult male rats led to a strong induction (up to approximately 10-fold) of liver P450R ...

The late genetic region of the T3 bacteriophage genome is transcribed by a phage-specified RNA polymerase, the product of T3 gene 1. In vitro, purified T3 RNA polymerase acting with T3 DNA template synthesizes six major RNA products, with molecular weights of 5.5 X 10(6), 4.2 X 10(6), 1.7 X 10(6), 0.87 X 10(6), 0.52 X 10(6), and 0.23 X 10(6). These are designated T3 RNA species I through VI, re...