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the Hypothalamus notes
Most pituitary hormones have more than one name, and abbreviated names are commonly used. The suffixes -trophic and -tropic are often used as if they meant the same thing. They don't, but arguments can be made for both. Here I favour -troph- over -trop-, for reasons that I will be happy to discuss with anyone who's interested.
The following releasing and inhibitory hormones (or factors) are well known. All except
dopamine are peptides, and most of them also occur in neurons in other parts of the central and peripheral nervous systems.
Each hormone's release from the anterior lobe is controlled mainly by its releasing factor, except
prolactin, the release of which is restrained by dopamine.
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--------------------------Hormones of the hypophysis and hypothalamus
and their actions
Nomenclatural note: The word hypophysis means the pituitary gland together with its stalk and the median eminence.
Posterior lobe hormones
Increased permeability of renal distal and collecting tubules to water, resulting in increased reabsorption and reduced urine output
Contraction of mammary myoepithelial cells (milk ejection); contraction of uterus, especially when sensitized by oestorgensAnterior lobe hormones
Anterior lobe hormones are secreted by different cell types, with names such as corticotrophs, somatotrophs etc.
Stimulates production of glucocorticoids by adrenal cortex.
Stimulates production of thyroxine and triiodothyronine by the thyroid gland.
Stimulates growth of bones and other organs. These actions are mediated in large part by insulin-like growth factors (ILGFs) secreted by cells in the liver and elsewhere in respones to STH.
Stimulates growth of the ovarian follicle and secretion of oestrogens.
In the male, FSH stimulates the Sertoli cells of the testis, which contribute to maturation of spermatozoa.
Stimulates ovulation of the mature follicle, the subsequent development of a corpus luteum, and secretion of progesterone.
In the male, LH stimulates the interstitial (Leydig) cells of the testis to produce androgens.
FSH and TSH are the gonadotrophins - pituitary hormones that stimulate the secretion of steroid hormones (androgens, oestrogens and progestogens) by endocrine cells in the ovary or testis.
Stimulates growth and function of the mammary gland. [ Prolactin also has several other known actions, of uncertain physiological significance. ]Releasing and inhibiting hormones
These are secreted by neurosecretory neurons in the tuber cinereum, anterior hypothalamic area and preoptic area, and delivered to the anterior lobe by the pituitary portal system.
Stimulates the corticotrophs to secrete ACTH.
Stimulates the thyrotrophs to secrete TSH.
Stimulates the somatotrophs to secrete STH.
Inhibits STH release (though this may not be its normal function).
Stimulates secretion of both FSH and LH by gonadotrophs.
Inhibits the release of prolactin by mammotrophs.
the Hypothalamus notes
Last updated: November 2002