Endocrinology

Hypocalcemia and Hypercalcemia

Hypocalcemia and Hypercalcemia

Calcium is required for efficient cellular function and signaling, as well as neuromuscular transmission, cardiac contractility, hormone secretion, and blood coagulation. Extracellular calcium concentrations are controlled within an extremely narrow range thanks to a number of feedback processes including parathyroid hormone (PTH) and the active vitamin D metabolite 1,25-dihydroxyvitmin D [1,25(OH)2D]. By activating the calcium…

Disorders of Sex Development

Disorders of Sex Development

Sex development starts in utero but progresses with the completion of sexual maturity and reproductive capacity into young adulthood. Three primary components may be classified into the major determinants of sex development: chromosomal sex, gonadal sex (sex determination), and phenotypic type (sex differentiation). Abnormalities at any of these stages can contribute to sex development disorders…

C-Peptide

C-Peptide

C-Peptide (Connecting peptide) is the binding peptide cleaved in proinsulin insulin processing. Responsive immunoassays in blood and urine can easily detect it. Serum C-peptide is a particularly useful marker of endogenous insulin secretion (a synthetic insulin that does not contain C-peptide). A patient is being diagnosed with exogenous (injected) insulin at the same time, while…

Thyroid Disorders

Thyroid Disorders

Thyroid tissue is made up of colloid, which includes iodinated thyroglobulin. Thyroglobulin is a big molecule that is synthesized by the surrounding follicular cells and from which thyroxine is produced and processed in colloid. Thyroid neuroendocrine cells (parafollicular or C cells) release calcitonin, a physiologically active peptide, and are situated between the follicular cells. Calcitonin…