Comparison of Biological and Chemical Assay of Thyroid

The biological and chemical examination of thyroid samples has demonstrated the inadequacy of the B.P. assay, which is based upon the determination of so-called “thyroxine iodine”. It is suggested that, in the absence of specific methods for determining thyroxine and tri-iodothyronine in thyroid, the chemical assay should be replaced by a biological assay.

The mouse anoxia method is shown to be suitable for this purpose. The potencies of samples assayed thus over the past 3 years, together with chemical data and clinical comments are presented. The relative activities of the thyroid constituents 3,5,3′,5′-tetra-iodo-L-thyronine (L-thyroxine), 3,5,3′-tri-iodo-L-thyronine, 3,5-di-iodo-L-tyrosine, 3-mono-iodo-L-tyrosine, as determined by the mouse anoxia method, are in good agreement with their reported clinical effectiveness.

The relationship of delayed hypersensitivity and circulating antibody to experimental allergic thyroditis in inbred guinea pigs

Strain 13 histocompatible guinea pigs developed allergic thyroiditis after immunization with thyroid extracts derived from the same strain or from other strains of guinea pigs. This thyroiditis appeared as early as 5 days after immunization, and by 7 weeks was uniformly present and generally severe. 7 weeks after immunization, the anti-thyroid antibody titer correlated with the presence and degree of thyroiditis. However, at certain other times after immunization, the titer did not correlate with the thyroiditis. By contrast, all animals with thyroiditis, which were skin-tested with thyroid extract, exhibited delayed hypersensitivity. Moreover, all those which failed to respond with delayed reactions, when skin-tested, had not developed thyroiditis. The present work correlates the presence of experimental allergic thyroiditis with delayed hypersensitivity.

The effect of hyperthyroidism induced by thyroideum siccatum on the central nervous system: an electron microscopic study

Ten adult male rats were administered orally with thyroideum siccatum every day to produce a hyperfunctional state of thyroid hormone. They were examined electron microscopically for the fine structure of the brain. Clinically, experimental rats lost in weight, manifested a hyperactive, irritative attitude, and were in an aggressive state. Electron microscopically, the nerve cells showed a slight increase in the number of mitochondria in the frontal cortex, spiral and petaloid variation of ER in the thalamus. The specific findings in the experimental rats were variations of synapse observed in the frontal and temporal cortex, gyrus hippocampi, and thalamus, centering around the hypothalamus. They included meandering of the presynaptic membrane, formation of vacuoles by the presynaptic membrane, saccate projection of this membrane to the postsynapse, and changes in vacuoles which were torn off and fell into the dendrite. These variations occurred in the synaptic membrane and ER, probably because synthesis of the membrane had been accelerated remarkably by the action of thyroid hormones. They were considered to have brought about abnormalities to the conductive and transmission system. They seemed to be closely related with emotional disturbances and psychic symptoms, since such variations were particularly apparent in the hypothalamus.

The metabolic and functional effects of thyroid hormone excess in rats

Oral administration of thyroid powder for 21 days produces hyperglycemia, hypocholesterolemia, increase of the energetic metabolism ratio and diminishing of the anaerobic metabolism ratio. Prolonged oral administration (30--45 days) induces involution of the thyroid gland, symptoms of an aggravated thyrotoxic hepatosis, hypoglycemia, hypocholesterolemia, a significant increase of the energetic metabolism and of the anaerobic metabolism ratios.