Thyroid-stimulating hormones properties

For demonstrating the properties of the multiplex IPCR and covalent antibody-DNA conjugates (see Section 2.1.3), a number of hormones such as human thyroid stimulating hormone or chorionic gonadotropin were simultaneously detected by the workgroup of Ebersole [38, 41]. In the... 

Thyrotropin alpha has the biologic properties of pituitary TSH. It binds to TSH receptors on both normal thyroid and differentiated thyroid cancer cells. The TSH-activated receptor stimulates intracellular adenylyl cyclase activity. Increased cAMP production causes increased iodine uptake and increased production of thyroid hormones and thyroglobulin. 

The properties of the ihicrosomal 26-hydroxylase seem to differ from those of the other microsomal side-chain hydroxylations. Treatment with phenobarbital had little or no influence on 26-hydroxylation of 5yS-cholestane-3a,7a,12a-triol but stimulated the other hydroxylations up to 8-fold [126]. Thyroid hormone stimulated the microsomal 26-hydroxylase, which might be of importance for the regulation of the ratio between cholic and chenodeoxycholic acid in the rat (cf. below). Biliary obstruction inhibited [127] whereas biliary drainage and starvation have little or no effect [126]. 

Another experimental result compatible with direct effects of the hormone on nerve cell activity comes from studies showing earlier heart rate stimulating properties of intrathecally as compared with intravenously delivered T3 to hypothyroid rats (Fig. 7). Thus, though sparse, presently available functional results demonstrate that thyroid hormones play a continuing role in adult brain, which may be synaptically mediated. 

It has been observed that in man androgens are converted principaUy to 5a-steroids when blood levels of thyroid hormone were high and to 5j8-steroids when these levels were low [390]. It appears that th5n oid hormone possesses the property to stimulate hepatic 5a-steroid reductase or inhibit 5jS-reductase. 

---