Volume 3 Issue 3, March 2007

Growth hormone abuse is prevalent in sport because of the perceived benefits on lean muscle mass, strength, and performance. As discussed in this Viewpoint, however, inappropriate use of growth hormone might be associated with adverse effects, such as hypertension and cardiomyopathy, particularly when athletes concurrently abuse anabolic androgen steroids.

Primary aldosteronism in its normokalemic form accounts for about 10% of cases of hypertension. This Review details the etiology, and the clinical and biochemical features of the subtypes of primary aldosteronism. It also describes the advantages of the various screening and confirmatory strategies and the available treatment options.

This Review covers clinical characterization of endoderm-derived endocrine tumors, apart from small-cell carcinoma. Classification is complex but crucial because it impacts diagnosis, imaging, prognosis and therapy; nevertheless, the tumors can be managed as a single clinical entity. Diagnosis of poorly differentiated endocrine tumors in particular has an important impact on therapy.

The recent increase in detection of thyroid papillary microcarcinoma by imaging studies, including ultrasonography, has led to a new problem: how should we handle these minute lesions? They can show multifocality and lymph-node metastasis, but are usually slow growing. This Review suggests that observation without surgery is an attractive alternative to surgery, at least in low-risk patients.

Gene control mediated by nuclear thyroid hormone receptors is important for normal brain maturation. As discussed in this Review, the lack of thyroid hormone ligand, experimental deletion of a receptor, or expression of dominant negative mutant receptors can have different effects on gene transcription and therefore on brain development and function.

As discussed in this Review, thyroid cancer tissue alters the metabolism of iodide by affecting gene expression and post-transcriptional processes and can thereby decrease delivery of radioiodide during screening and therapy. This Review details these processes and discusses the clinical implications for different patient groups.

Hyperglycemia often occurs in patients who are acutely ill. This Review details the findings of several recent studies showing that using insulin to maintain normoglycemia for a few days significantly improved survival and morbidity in patients in medical or surgical intensive care units.

The measurement of prolactin levels is commonly requested for patients with reproductive disorders. This Review describes the causes of hyperprolactinemia and the steps to take once it is suspected. In particular, the various pitfalls that can cause falsely low or high prolactin levels in immunoassays are detailed.

Novel strategies are needed to treat metastatic medullary thyroid cancers (MTC), and gene therapy offers several potential avenues for this and many other types of tumors. This Review outlines the many MTC-specific strategies currently under investigation experimentally and describes several that are now being assessed in clinical trials in a range of other tumor types.

Insulin-like growth factor 1 is a major effector of growth hormone. IGF1 binds the IGF1 receptor with high affinity and the insulin receptor with lower affinity. IGF1 has actions distinct from growth hormone in carbohydrate, lipid and protein metabolism; it can lower blood glucose levels and might prove efficacious for diabetes.

In patients with primary hyperparathyroidism, surgical removal of all pathologic parathyroid tissue is the only definitive therapy. This Case Study reports a patient with persistent hyperparathyroidism due to a second ectopic adenoma, necessitating preoperative localization studies and illustrating a number of aspects of the diagnosis and management of primary hyperparathyroidism.