Adenohypophysis Health Dictionary

Also known as the pituitary body and the hypophysis, this is an ovoid structure, weighing around 0·5 gram in the adult. It is attached to the base of the BRAIN, and lies in the depression in the base of the skull known as the sella turcica. The anterior part is called the adenohypophysis and the posterior part the neurohy-P pophysis. The gland is connected to the HYPOTHALAMUS of the brain by a stalk known as the hypophyseal or pituitary stalk.

The pituitary gland is the most important ductless, or endocrine, gland in the body. (See

ENDOCRINE GLANDS.) It exerts overall control of the endocrine system through the media of a series of hormones which it produces. The adenohypophysis produces trophic hormones (that is, they work by stimulating or inhibiting other endocrine glands) and have therefore been given names ending with ‘trophic’ or ‘trophin’. The thyrotrophic hormone, or thyroid-stimulating hormone (TSH), exerts a powerful in?uence over the activity of the THYROID GLAND. The ADRENOCORTICOTROPHIC HORMONE (ACTH) stimulates the cortex of the adrenal glands. GROWTH HORMONE, also known as somatotrophin (SMH), controls the growth of the body. There are also two gonadotrophic hormones which play a vital part in the control of the gonads: these are the follicle-stimulating hormone (FSH), and the luteinising hormone (LH) which is also known as the interstitial-cell-stimulating hormone (ICSH) – see GONADOTROPHINS. The lactogenic hormone, also known as prolactin, mammotrophin and luteotrophin, induces lactation.

The neurohypophysis produces two hormones. One is oxytocin, which is widely used because of its stimulating e?ect on contraction of the UTERUS. The other is VASOPRESSIN, or the antidiuretic hormone (ADH), which acts on the renal tubules and the collecting tubules (see KIDNEYS) to increase the amount of water that they normally absorb.... pituitary gland

Linn.

Family: Gramineae; Poaceae.

Habitat: A cereal and fodder crop of Europe and America; also cultivated in India.

English: Oat, Common oat.

Ayurvedic: Yavikaa. (Indian sp. is equated with A. byzantina C. Koch.)

Unani: Sult (Silt), Jao Birahnaa, Jao Gandum.

Action: Nervine tonic (used in spermatorrhoea, palpitation, sleeplessness), cardiac tonic (used in debility), stimulant, antispasmodic, thymoleptic, antidepressant (used in menopausal phase). Also used in diarrhoea, dysentery, colitis. Externally, emollient.

Key application: Oat straw— externally in baths for inflammatory and seborrhoeic skin diseases. (German Commission E.) The effect on blood sugar is less than that from most of the fiber-containing herbs and foods. (Sharon M. Herr.)

The seeds contain proteins and prolamines (avenins); C-glycosyl flavones; avenacosides (spirostanol glycosides); fixed oil, vitamin E, starch.

Silicon dioxide (2%) occurs in the leaves and in the straw in soluble form as esters of silicic acid with polyphenols and monosaccharides and oligosaccharides.

Oat straw contains a high content of iron (39 mg/kg dry weight), manganese (8.5 mg) and zinc (19.2 mg).

In an experimental study, oat straw stimulated the release of luteinizing hormone from the adenohypophysis of rats. (Expanded Commission E Monographs.)

An alcoholic extract of green oats was tried on opium addicts. Six chronic opium addicts gave up opium completely, two reduced their intake and two showed no change following regular use of 2 ml three times daily (human clinical study). A significant diminish- ment of the number of cigarettes used by habitual tobacco smokers resulted from using 1 ml (four times daily) of fresh Avena alcoholic extract of mature plants; however, a few studies gave disappointing results. (Francis Brinker.)

Oat polyphenol composition prevented the increase of cholesterol and beta-lipoprotein of blood serum of fasting rabbits. Antioxidant property of the oat flour remains unaffected by heat. Homoeopathic tincture of seeds is used as a nervine tonic. Beta-glucan from the oats stimulated immune functions.

Avenacosides exhibit strong anti- fungal activity in vitro.... avena sativa

ACROMEGALY or gigantism is the result of the overactivity of, or tumour formation of cells in, the adenohypophysis which produces GROWTH HORMONE (see also PITUITARY GLAND). If this overactivity occurs after growth has ceased, acromegaly arises, in which there is gross overgrowth of the ears, nose, jaws, and hands and feet. DWARFISM may be due to lack of growth hormone.

DIABETES INSIPIDUS, a condition characterised by the passing of a large volume of URINE every day, is due to lack of the antidiuretic hormone (see VASOPRESSIN). Enhanced production of the ADRENOCORTICOTROPHIC HORMONE (ACTH) leads to CUSHING’S SYNDROME. Excessive production of PROLACTIN by micro or macro adenomas (benign tumours) leads to hyperprolactinaemia and consequent AMENORRHOEA and GALACTORRHOEA. Some adenomas do not produce any hormone but cause effects by damaging the pituitary cells and inhibiting their hormone production.

The most sensitive cells to extrinsic pressure are the gonadotrophin-producing cells and the growth-hormone producing cells, so that if the tumour occurs in childhood, growth hormone will be suppressed and growth will slow. Gonadotrophin hormone suppression will prevent the development of puberty and, if the tumour occurs after puberty, will result in amenorrhoea in the female and lack of LIBIDO in both sexes. The thyroid-stimulating hormone cells are the next to suffer and the pressure effects on these cells will result in hypothyroidism (see under THYROID GLAND, DISEASES OF).

Fortunately the ACTH-producing cells are the most resistant to extrinsic pressure and this is teleologically sound as ACTH is the one pituitary hormone that is essential to life. However, these cells can suffer damage from intracellular tumours, and adrenocortical insu?ciency is not uncommon.

Information about these disorders may be obtained from the Pituitary Foundation.... pituitary-linked disorders