Endocrine Abstracts

HMG CoA reductase, the rate-limiting enzyme in the mevalonate pathway, is 14 steps away from cholesterol synthesis. Statins dramatically reduce the serum concentration of LDL cholesterol by inhibiting this enzyme, but may similarly lower the concentration of many other compounds in the pathway, including ubiquinone (possibly the mechanism of statin-induced rhabdomyolysis though the evidence is far from conclusive). Certain drugs are important co-factors in statin-induced rhabd...

Type 1 diabetes (T1D) is an autoimmune disease, the clinical onset of which most frequently presents in children and adolescents who are genetically predisposed. T1D is characterized by a T-cell mediated, specific, insulin-producing beta cell destruction. The well-differentiated and specialized islet beta cells seem to physiologically retain the ability to compensate for the cells lost by reproducing themselves, while undifferentiated cell sources may help in generating new on...

Bone is a dynamic tissue, maintained and repaired by the actions of, osteoclasts, osteoblasts and osteocytes, together with a variety of bone marrow cells, stromal cells and endothelium. Osteoblasts lay down bone and this is subsequently remodelled by osteoclasts. Osteocytes act mainly as mechanosensors. Osteoclasts are of haemopoietic origin, whereas osteoblasts are derived from mesenchymal stem cells. During cell differentiation and in mature cells, cell adhesion molecules a...

In April 1986, the explosion at the Chernobyl nuclear power plant resulted in widespread radioactive contamination in southern Belarus, northern Ukraine and southern Russia. The main radiation dose was to the thyroid and came from exposure to I131 from drinking contaminated milk. A substantial increase in thyroid cancer incidence in children was observed as early as 5 years after the accident. The first report in 1992 described 114 cases of thyroid cancer in childre...

Parathyroid hormone(PTH) is released by the parathyroid glands to regulate the concentration of ionised calcium in extracellular fluid.Any change in ionised calcium is followed by reciprocal changes in PTH secretion. PTH acts on the kidney to increase the renal tubular reabsorption of calcium and to increase the synthesis of the hormonal metabolite of vitamin D which enhances the intestinal absorption of calcium. Prolonged PTH secretion increases calcium release from bone as a...

The treatment of growth hormone deficiency (GHD) with growth hormone (GH) leads to increased bone turnover, new bone formations and increased bone mineral density (BMD). This response is paralleled by an increased demand for bone substrate. We present a case in which the increased turnover induced by GH treatment revealed previously occult metabolic bone disease.The patient a 56-year-old male with panhypopituitarism following treatment for acromegaly, co...

Beta-cell hyperplasia is an important adaptive mechanisms to maintain normoglycemia during physiological growth and in obesity. Increasing evidence suggests that the β-cell mass is dynamic and that increase demands on insulin secretion in insulin resistance and pregnancy can lead to rapid and marked changes in the β-cell mass. The mass of β-cells is governed by the balance of ß cell growth (replication) and by β-cell death (apoptosis). The molecular ba...

A decrease in the number of functional insulin producing beta-cells contributes to the pathophysiology of type 2 diabetes. The putative factors responsible for the maladaptation of beta-cells include hyperglycaemia, cytokines, dyslipidemia and leptin. Islet inflammation, autoimmunity and some drugs may be secondary modulators. Predetermined amount of beta-cell mass, sensitivity to pro-apoptotic signals and regeneration potential of beta-cells are predisposing factors. The mech...

Critical illness due to sepsis, trauma, surgery, organ failure or burns is associated with dramatic effects on most hormonal axes. Complex changes occur at the hypothalamic, pituitary, circulatory and tissue levels of hormone action. In the early stages of critical illness these changes appear to be adaptive but this may not be the case in prolonged illness. Common problems faced by endocrinologists are the recognition of pre-existing endocrine disorders in critically ill pati...

Nuclear pore complexes (NPCs) facilitate the transport of macromolecular cargoes across the nuclear envelope by carrier molecules. The energy for this active transport mechanism is provided by the Ras-family GTPase, Ran, that orchestrates most nuclear trafficking cycles. The RanGEF (RCC1) is located in the nucleus while its GAP is located in the cytoplasm. The nuclear import of steroids, bound to their receptor, is mediated by importins alpha and beta. In the cytoplasm, import...