Although a substantial coronary angiogenesis occurs after thyroid hormone treatment, its regulation and relationship to cardiac hypertrophy are not understood. This study was designed to determine (1) the onset of capillary proliferation, (2) the sites of capillary proliferation, and (3) whether basic fibroblast growth factor (bFGF) upregulation occurs in response to thyroxine administration. M...

The effects of altered thyroid state on the antioxidant defense system in the liver of differently aged rats were examined. Male rats aged 15, 45 and 75 days were treated with L-thyroxine, T4 (40 μg/100 g body mass, s.c., one dose per day) for 14 days (finally aged 30, 60 and 90 days, respectively). The following antioxidant defense enzymes were measured: superoxide dismutases (both copper zinc...

Thyroid hormone resistance (THR) is a rare syndrome of reduced end organ sensitivity. Patients with THR have elevated serum free thyroxine (FT4), free triiodothyronine (FT3), but normal or slightly elevated serum thyrotropin values. The characteristic clinical feature is goitre without symptoms and metabolic consequences of thyroid hormone excess. THR can be classified on the basis of tissue re...

Concannon, Patrick W., V. Daniel Castracane, Richard E. Rawson, and Bud C. Tennant. Circannual changes in free thyroxine, prolactin, testes, and relative food intake in woodchucks, Marmota monax. Am. J. Physiol. 277 (Regulatory Integrative Comp. Physiol. 46): R1401–R1409, 1999.— Woodchucks (n 5 12–14/group) with circannual cycles entrained to northern versus southern hemisphere photoperiods wer...

Iron deficiency anemia is associated with lower plasma thyroid hormone concentrations in rodents and, in some studies, in humans. The objective of this project was to determine if plasma triiodothyronine (T3) and thyroxine (T4) kinetics were affected by iron deficiency. Studies were done at a near-thermoneutral temperature (30 degrees C), and a cool environmental temperature (15 degrees C), to ...

Normalization of basal thyrotrophin (TSH) level is used as the endpoint in L-thyroxine (L-T4) therapy of primary hypothyroidism. However, several reports have questioned the reliability of this index because of seasonal variation of TSH. Therefore, we studied 85 consecutive patients with primary hypothyroidism over a period of 3.5 y. In these patients, TSH response (delta TSH) to intravenous th...

The effect of isoflurane (Forane) anaesthesia and surgery on thyroid function was investigated in nine male patients. Isoflurane anaesthesia alone for 30 minutes prior to the start of surgery increased plasma triiodothyronine uptake (T3U) and thyroxine (T4) level by 18 and 20 per cent, respectively. Free thyroxine index (FTI) values in blood increased by 62 per cent during the same period. One ...

Ethinyl estradiol was administered orally in a daily dose of 0.18-0.3mg for seven days to subjects with normal and abnormal thyroid function, and the changes of several parameters of the thyroid function during estrogen admin istration were investigated. The concentration and maximum T4 binding capacity of thyroxine-binding prealbumin (TBPA) were estimated by polyacrylamide gel electrophoresis....

*Correspondence to: John H Lazarus MD, Thyroid Research Group, Cardiff School of Medicine, Cardiff, United Kingdom, E-mail: [email protected] Abstract The aim of this review is to indicate the current position on the role of thyroxine (T4) and fetal brain development with particular relevance to the human situation. Adequate maternal iodine nutrition and maternal circulating thyroxine (T4) conce...

The effect of trypanosome infection on the plasma levels and ratios of tri-iodothyronine (T3) and thyroxine (T4) as well as the activity of mitochondrial adenosine triphosphatase (ATPase) were investigated. Three groups of sexually mature white New Zealand rabbits were used. Group 1 consisted of the normal non-infected rabbits, group 2 were experimentally infected with Trypanosoma congolense an...