Endocrine Abstracts

The Na+/I- symporter (NIS) is an intrinsic plasma membrane glycoprotein that mediates active I- transport in the thyroid follicular cells, the first step in thyroid hormone biosynthesis. Na+/I- symport occurs with a two Na+ per one I- stoichiometry. Endogenous functional expression of NIS in thyroid cancer is the foundation for the single most effective and most side effect-free anti-cancerous targete...

A variety of rapid responses to steroid hormones have been identified during the last decade. In contrast to classical actions mediated via nuclear receptors with a time lag of hours, rapid actions occur within seconds or minutes via second messenger signalling cascades. Classical genomic actions are well-defined and sensitive to transcription and protein synthesis inhibitors. Steroid hormones enter the cell by diffusion or via transport proteins and bind to cognate receptors ...

We have revisited the actions of hormones from the anterior pituitary, notably TSH, on bone and bone cells. Traditionally, the bone loss in hyperthyroidism has been attributed solely to elevated circulating levels of thyroid hormones. The role of TSH, which is reduced in all forms of hyperthyroidism, as well as during thyroxine suppressive therapy for thyroid cancer, has never been investigated. We found that haploinsufficiency of the TSH receptor in mice led to bone loss with...

Within the pituitary, GnRH acts via type I GnRH receptors to cause a Gq/11 mediated activation of PLC and consequent acute stimulation of gonadotrophin secretion and chronic regulation of gonadotrophin and GnRHR synthesis. The therapeutic effects of GnRH analogues are primarily (if not entirely) dependent upon activation, desensitisation or blockade of this system. There is also abundant evidence for expression of GnRHRs in extra-pituitary sites including the CNS, t...

The renin angiotensin system (RAS) is well known for its role in the regulation of blood pressure and fluid homeostasis. Blockers of the RAS are widely used for the treatment of hypertension, cardiac failure and chronic renal insufficiency. Angiotensin I converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are usually quite well tolerated. In addition to the systemic effect of the RAS, evidence for an autocrine/paracrine role of this system has been w...