The Probert Encyclopaedia of Medicine

PITUITARY GLAND

The pituitary gland (or hypophysis),is a gland within the brain concerned with regulating growth and regulating other ductless glands. The pituitary gland , consists of three lobes, the anterior lobe, the intermediate lobe, which in primates is present for only a short part of the life span, and the posterior lobe. It is situated at the base of the brain and has been called the master controlling gland of the body. The anterior and the posterior lobes of the pituitary secrete different hormones. The anterior lobe secretes various hormones that stimulate the function of other endocrine glands, for example, adrenocorticotropic hormone, or ACTH, which stimulates the adrenal cortex; thyroid- stimulating hormone, or thyrotropin, known as TSH; follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which stimulate the sex glands; and prolactin, which, with other special hormones, influences milk production of the mammary gland.

In addition, the anterior pituitary is the source of growth hormone, also called somatotropin, which promotes the development of body tissues, particularly of bone matrix and muscle, and influences carbohydrate metabolism. The anterior pituitary also secretes a hormone called melanocyte-stimulating hormone, which regulates the intensity of pigmentation in pigmented cells. In the 1970s scientists found that the anterior pituitary also produces substances called endorphins. These are peptides that act on the peripheral and central nervous systems to reduce sensitivity to pain. The hypothalamus, secretes an antidiuretic hormone named vasopressin, which is stored in the posterior lobe of the pituitary gland. The posterior lobe of the pituitary also stores another hormone secreted by the hypothalamus. This hormone, known as oxytocin, stimulates muscular contractions, especially of the uterus, and ejection of milk from lactating mammary glands. Not long ago it was found that secretion of three anterior pituitary hormones is under regulation of the hypothalamus: thyrotropin secretion is stimulated by thyrotropin-releasing factor (TRF), and luteinizing- hormone secretion by luteinizing-hormone releasing hormone (LHRH). Release of growth hormone is inhibited by somatostatin, which is also made by the pancreas.
Research Pituitary gland