AI Article Synopsis
- Thyroxine 5'-deiodinase activity in male rat Harderian gland homogenates depends on tissue concentration, optimal pH of 7.0, and temperature range of 4-37°C.
- Dithiothreitol (DTT) increases the enzyme activity, while propylthiouracil (PTU) moderately inhibits it, and iopanoic acid (IA) has a strong inhibitory effect.
- Thyroidectomy significantly boosts enzymatic activity, but this effect is negated by iopanoic acid; activity also varies throughout the day, peaking around 3:00 AM.
Article Abstract
Thyroxine 5'-deiodinase activity was studied in male rat Harderian gland homogenates. The reaction rate was proportional to the tissue content in the homogenate and dependent on pH, with an optimum pH of 7.0, and temperature, between 4-37 degrees C. 5'-deiodinase activity was increased by dithiothreitol (DTT) in a dose-dependent manner, and inhibited moderately by propylthiouracil (PTU) and strongly by iopanoic acid (IA). Thyroidectomy enhanced the enzymatic activity (30-fold above the control value) but this increase is totally prevented by the in vivo iopanoic acid treatment. Thyroxine 5'-deiodinase activity was also dependent on T4 concentration (Km = 3.3 nM; Vmax = 10 fmol 125I-released/mg protein/h) and exhibited a nyctohemeral rhythmicity with a maximal activity at 03.00 h (4-fold above basal values) and minimal activity between 12.00-21.00 h.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/0024-3205(87)90638-2 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Oatmeal and wheat flour as the sources of thyroid peroxidase and proinflammatory enzymes modulators in the prevention of thyroid diseases.
Sci Rep
January 2025
Department of Biochemistry and Food Chemistry, University of Life Sciences, Skromna Str. 8, Lublin, 20-704, Poland.
Polyphenolic plant compounds possess nutritional and pro-healthy potential, reducing the risk of auto-inflammatory and neoplastic diseases. However, their interference with the progression of thyroid gland dysfunctions has remained largely unaddressed. For this purpose, we combined the analyses of phenolic content and antioxidative activity with the thyroid peroxidase (TPO), lipoxygenase (LOX), xanthine oxidase (XO) and cyclooxygenase-2 (COX-2) activity assays, isobolographic approach and the estimation of thyroid cancer cells' proliferation and motility in vitro.
View Article and Find Full Text PDFQRFP43 modulates the activity of the hypothalamic-pituitary-thyroid axis in female sheep.
Sci Rep
January 2025
Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3, Jabłonna, 05-110, Poland.
Since the early discovery of QRFP43, intensive research has been primarily focused on its role in the modulation of food intake. As is widely recognised, the regulation of the body's energy status is a highly complex process involving numerous systems, hormones and neurotransmitters. Among the most important regulators of energy status, alongside the satiety and hunger centre located in the hypothalamus, is the HPT axis, which directly and indirectly affects the regulation of metabolism in all cells of the body.
View Article and Find Full Text PDFATF4 Exacerbates Cerebral Infarction-Induced Sensory Dysfunction via HDAC1/DNMT1/GPX4 Signaling.
Crit Rev Eukaryot Gene Expr
December 2024
Department of General Practice, The First People's Hospital of Yunnan Province, 650032, China; The Affiliated Hospital of Kunming University of Science and Technology, Kunming, Yunnan, 650032, China.
Cerebral infarction is the main cause of death and long-term disability worldwide. Neuronal degeneration and limp sensory dysfunction are the secondary damages induced by cerebral infarction. This study aimed to investigate the roles of activating transcription factor 4 (ATF4) in cerebral infarction and the underlying molecular mechanisms.
View Article and Find Full Text PDFImplications of thyroid-related autoantibodies in patients with Sjögren's syndrome without overt thyroid diseases.
Clin Exp Rheumatol
December 2024
Division of Rheumatology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam; Department of Internal Medicine, Seoul National University College of Medicine, Seoul; and Department of Medical Device Development, Seoul National University College of Medicine, Seoul, Republic of Korea.
Objectives: We investigated the prevalence of anti-thyroid autoantibodies and thyroid dysfunction, and their association with clinical and laboratory features in Korean patients with primary Sjögren's syndrome (pSS) without overt thyroid illnesses.
Methods: We consequently included 196 pSS patients (190 women) and cross-sectionally collected clinical and laboratory data including the EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) and Patient Reported Index (ESSPRI). The fatigue-dominant group was defined as those in the highest quartile of the fraction of fatigue, calculated as the ESSPRI fatigue score divided by the total ESSPRI score.
Comparative evaluation of rat and human in vitro assays for evaluation of thyroid toxicity.
ALTEX
December 2024
KaLy-Cell SAS, Plobsheim, France.
The effects of ten test chemicals towards thyroid sodium-iodide symporter (NIS), thyroid peroxidase (TPO), and deiodinases (DIOs) type I, II, and III were evaluated in in vitro rat and human systems and compared. Test chemicals known to directly affect TH levels in vivo were confirmed to effectively inhibit at least one of the tested in vitro endpoints, without significant disparities between species, and the tested compounds known to not affect thyroid function, were found ineffective. Interestingly, Iodide Transport Blocker 5, a potent non-competitive iodine uptake inhibitor, exhibited effects beyond direct NIS inhibition, by impacting NIS function through ATP depletion, and also inhibited TPO and DIO1/2 enzymes, although to a lesser extent.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!