Synthesis of thyroid hormones, thyroxine (T4) and tri-iodothyronine (T3), in the human fetus starts from 17 to 19th weeks of gestation. Despite the majority of normal pregnant women reaching adequate levels of circulating thyroid hormones, in some cases, women with normal pregnancies have low level of free T4 during first trimester of pregnancy, suggesting that T4 action may be compromised in t...

We compared the specificities of transport mechanisms for uptake and efflux of thyroid hormones in cells of the human choriocarcinoma cell line, JAR, to determine whether triiodothyronine (T3), thyroxine (T4) and reverse T3 (rT3) are carried by the same transport mechanism. Uptake of 125I-T3, 125I-T4 and 125I-rT3 was saturable and stereospecific, but not specific for T3, T4 and rT3, as unlabell...

We investigated helper and suppressor functions to B-cell responses and T-T cell interactions of purified T4 and T8 cells from 20 untreated patients with B-cell chronic lymphocytic leukemia (CLL). Appropriate mixtures of purified T4 or T8 cells from patients with CLL were cultured with purified B cells or T4 and B cells from normal donors for 7 days with pokeweed mitogen (PWM). IgM, IgA, and Ig...

Short-term experimental diabetes mellitus (DM) produces a significant decrease in serum thyroid hormones, a decreased or normal serum thyroid-stimulating hormone (TSH) and a reduction in hepatic and renal T4-5'-deiodination. However, little is known about the effects of chronic diabetes mellitus on the pituitary-thyroid axis function. We evaluated the changes induced by very short-term (6 days)...

crease in T4 secretion induced by iodine is not the result of an acute, sustained inhibition of T4 synthesis, but rather results from an abrupt decrease in the fractional rate of thyroidal T4 release.

The genomes of petite T4 phage particles presumably cannot circularize because they are deficient for a significant terminal segment and hence not terminally redundant like normal T4 genomes. Combined density- and 32P-labeling shows that the majority of such deficient DNA molecules can nevertheless replicate their entire length. Furthermore, the density-shift technique shows that replicated par...

Integration deficient (L) mutants of phage P22 can be complemented with L+ phage to yield L mutant lysogens. Once established the L prophage is stable in the absence of L+ function. Ultraviolet or thermal induction of L lysogens leads to product,ion of defective phage particles and low yields of infectious phage. The defective particles contain a normal amount of DNA but the DNA is mainly bacte...

A 28 year old woman with Hashimoto's disease was treated with desiccated thyroid and triiodothyronine (T3). She improved steadily during the first 2 to 3 months and thyroidal function tests turned to normal. Then, in spite of continuing treatment, her serum T4 level decreased gradually and she became fatigued. A serum T3 radioimmunoassay manifested an interference pattern suggested anti-T3 anti...

To study thyroid hormone and estrogen interactions in the central nervous system (CNS), the expression of estrogen sensitive genes was examined within the limbic-hypothalamic circuit. Estrogen up-regulates the expression of reproductively relevant neuropeptide messenger RNAs (mRNAs) encoding cholecystokinin (CCK) and enkephalin, peptides that stimulate lordosis. Estrogen down-regulates the expr...

CONTEXT Familial dysalbuminemic hyperthyroxinemia, characterized by abnormal circulating albumin with increased T4 affinity, causes artefactual elevation of free T4 concentrations in euthyroid individuals. OBJECTIVE Four unrelated index cases with discordant thyroid function tests in different assay platforms were investigated. DESIGN AND RESULTS Laboratory biochemical assessment, radiolabe...