We examined the extranuclear effects of thyroid hormones on human platelets. Pretreatment with DL-thyroxine or DL-triiodothyronine inhibited collagen-induced aggregation, in a dose-dependent manner, but other derivatives of thyroid hormone had no significant effects. In contrast to collagen, 12-O-tetradecanoylphorbol-13-acetate-induced aggregation was not affected by thyroid hormones at the sam...

BACKGROUND Previous experiments show that amphibian larvae are responsive to homeopathically prepared thyroxine. METHODS We studied the effect of a highly diluted and agitated thyroxine solution exposed to various electromagnetic fields on metamorphosis in highland Rana temporaria. The devices tested were: microwave oven, mobile phone, airport X-ray, and a red light barcode scanner. Animals w...

Thyroxine is the standard replacement therapy for patients with clinical hypothyroidism. However, there has been recent interest in examining the potential advantages of combined thyroxine and triiodothyronine treatment for the treatment of hypothyroidism. The authors review the nine studies to-date and conclude that the variability and limitations in study design make definitive and clinically...

We describe the existence of at least two thyroxine 5'-deiodinases in rat liver. They co-fractionate with NADPH-cytochrome c reductase, the marker enzyme for membranes of the endoplasmic reticulum. Subcellular-localization studies of the most active microsomal thyroxine 5'-deiodinase were performed under substrate saturation and at optimal pH 6.8. This enzyme was a Km(app.) of about 3 microM-th...

• It has been demonstrated that thyroid hormone and its analogues reduce plasma cholesterol levels both in hypoand in euthyroid individuals; and also that D-thyroxine is much less toxic and less calorigenic than L-thyroxine. Katz and Pick reported that thyroid hormone given to chicks on an atherogenic diet, either as desiccated thyroid or thyroxine, suppressed hypercholesterolemia, but the effe...

The ipsilateral retinothalamic projection in Xenopus laevis normally first appears at about stage 54, at a time when a number of other changes known to be dependent on a rise in circulating levels of thyroxine begin to occur. We have investigated the role of thyroxine in the development of the ipsilateral retinothalamic projection by studying retinal projections and patterns of retinal histogen...

In continuation of our studies on the metabolic processes involved in furnishing energy to the mammalian sperm cell a study has been made of the effect of certain metabolic accelerators. Carter (1) has reported that the respiration of rabbit epididymal spermatozoa may be increased by thyroxine by as much as 200 per cent under certain conditions, and has postulated a r61e of thyroxine in the mat...

Effect of Thyroxine was studied in histamine induced bronchospasm in guinea pigs. Chronic treatment with the drug significantly protected against experimental bronchospasm. Thyroxine also potentiated salbutamol evoked bronchodilation in this experimental model. Up-regulation of beta-2 adrenoceptors in bronchial smooth muscle may be the probable mechanism of action of thyroxine.

The effects of the administration of 0.5 or 1 mg/kg of 1-thyroxine for 3 or 16 days were studied in 55 New Zealand white rabbits. Heart size was 29% above control after 16 days of 1-thyroxine, despite lower body weights. In an anesthetized open-chest animal, regional microspectro-photometric observations of small arteries and veins to determine oxygen extraction were combined with regional bloo...

Recent studies have revealed an abnormality in the peripheral metabolism of thyroxine in patients with active untreated Graves' disease (1). In such patients, an abnormally large fraction of the extrathyroidal pool of thyroxine is degraded daily. Other authors have also observed an accelerated fractional turnover of thyroxine in patients with untreated Graves' disease (2, 3) and have postulated...