Category Archives: Endocrinology.

An introduction to endocrine disease

EPIDEMIOLOGY The commonest endocrine disorders, excluding diabetes mellitus , are: THYROID DISORDERS, affecting four to eight new patients per primary care physician per year. Most common problems are thyrotoxicosis, primary hypothyroidism and goitre. SUBFERTILITY, affecting 5-10% of all couples, often with an endocrine component, and increasingly treatable. MENSTRUAL DISORDERS AND EXCESSIVE HAIR GROWTH IN Y

Biological rhythms

The most important rhythms are circadian and menstrual. Circadian changes mean changes over the 24 hours of the day-night cycle and is best shown for the glucocorticoid cortisol axis. plasma cortisol levels measured over 24 hours-levels are highest in the early morning and lowest overnight. Additionally, cortisol release is pulsatile, following the pulsatility of pituitary ACTH. Thus ‘normal’ cor

Hormone action and receptors

Hormones act at the cell surface and/or within the cell. Many hormones bind to specific cell-surface receptors where they trigger internal messengers. Cell surface receptors are a family of ‘G proteins’ which bind the hormone on the cell surface and then activate socalled ‘second messengers’ via GTP. The second messengers include cyclic AMP for adrenocorticotrophic hormone (ACTH), lut


Introduction Hormones are chemical messengers produced by a variety of specialized secretory cells. They may be transported to a distant site of action (the classical ‘endocrine’ effect) or may act directly upon nearby cells (‘paracrine’ activity). In the hypothalamus, elsewhere in the brain and in the gastrointestinal tract there are many such cells secreting hormones, some of which h