PITUITARY HORMONES AND THIR CONTROL BY THE HYPOTHALAMUS
Pituitary Gland Lies in Sella Turcica
Hypophysis Connected to the hypothalamus by pituitary (hypophysial) stalk
Pars intermedia – avascular portion between anterior and posterior pituitary
Anterior Pituitary Originated from Rathke’s pouch – embryonic invagination of pharyngeal epi.
Adenohypophysis Hormones from this gland control most of metabolic functions of the body
1. Growth Hormones – protein formation, cell multiplication and cell
differentiation
2. Adrenocorticotropin (corticotropin)—ctrl secretion of adrenocortical
hormones w/c affects metabolism of glucose, proteins and fats
3. Thyroid-Stimulating Hormone (thyrotropin) – ctrl secretion rate of
thyroxine and triiodothyronine by thyroid gland
4. Prolactin – promotes mammary gland development and milk
production
5. Follicle Stimulating Hormone and Luteinizing Hormone—ctrl growth of
ovaries and testes and hormonal and reproductive activities
6. Antidiuretic Hormone (vasopressin) – ctrl rate of water excretion into
urine and conc of water in body fluids
7. Oxytocin – express milk from glands to nipples during suckling and
helps delivery of the baby
Cell types that secrete specific hormones
1. Somatotropes (30-40%) – hGH ; acidophils
↑GH by tumors –acidophilic tumors
2. Corticotropes (20%) --ACTH
3. Thyrotropes – TSH
4. Gonadotropes – gonadotropic hormones (LH,FSH)
5. Lactotropes -PRL
Posterior Pituitary Originated from neural tissue outgrowth from hypothalamus
Neurohypophysis o Presence of glial-type cells
Cell Bodies – synthesize post pituitary hormones
o Magnocellular neurons located in supraoptic and paraventricular
nuclei of hypothalamus.
Hypothalamus Controls secretions of pituitary gland
o Hormonal signals – anterior pituitary
Hypothalamic releasing and hypothalamic inhibiting
hormones / factors to anterior pituitary via hypothalamic-
hypophysial portal vessels
o Nervous signals – posterior pituitary
Collecting center for information concerning internal well-being of the body
Hypothalamic-Hypophysial Portal Where blood flows from hypothalamus to anterior pituitary
Blood vessels Median eminence—lowermost portion of hypothalamus connects inferiorly
with pituitary stalk.
o Hypothalamic releasing and inhibitory hormones are secreted into
the Medial Eminence and tuber cinereum – extension of
hypothalamic tissue into pituitary stalk
o These hormones are immediately absorbed into hypoythalamic-
hypophysial portal system and carried directly to sinuses of anterior
pituitary gland
Pituitary Gland Lies in Sella Turcica
Hypophysis Connected to the hypothalamus by pituitary (hypophysial) stalk
Pars intermedia – avascular portion between anterior and posterior pituitary
Anterior Pituitary Originated from Rathke’s pouch – embryonic invagination of pharyngeal epi.
Adenohypophysis Hormones from this gland control most of metabolic functions of the body
1. Growth Hormones – protein formation, cell multiplication and cell
differentiation
2. Adrenocorticotropin (corticotropin)—ctrl secretion of adrenocortical
hormones w/c affects metabolism of glucose, proteins and fats
3. Thyroid-Stimulating Hormone (thyrotropin) – ctrl secretion rate of
thyroxine and triiodothyronine by thyroid gland
4. Prolactin – promotes mammary gland development and milk
production
5. Follicle Stimulating Hormone and Luteinizing Hormone—ctrl growth of
ovaries and testes and hormonal and reproductive activities
6. Antidiuretic Hormone (vasopressin) – ctrl rate of water excretion into
urine and conc of water in body fluids
7. Oxytocin – express milk from glands to nipples during suckling and
helps delivery of the baby
Cell types that secrete specific hormones
1. Somatotropes (30-40%) – hGH ; acidophils
↑GH by tumors –acidophilic tumors
2. Corticotropes (20%) --ACTH
3. Thyrotropes – TSH
4. Gonadotropes – gonadotropic hormones (LH,FSH)
5. Lactotropes -PRL
Posterior Pituitary Originated from neural tissue outgrowth from hypothalamus
Neurohypophysis o Presence of glial-type cells
Cell Bodies – synthesize post pituitary hormones
o Magnocellular neurons located in supraoptic and paraventricular
nuclei of hypothalamus.
Hypothalamus Controls secretions of pituitary gland
o Hormonal signals – anterior pituitary
Hypothalamic releasing and hypothalamic inhibiting
hormones / factors to anterior pituitary via hypothalamic-
hypophysial portal vessels
o Nervous signals – posterior pituitary
Collecting center for information concerning internal well-being of the body
Hypothalamic-Hypophysial Portal Where blood flows from hypothalamus to anterior pituitary
Blood vessels Median eminence—lowermost portion of hypothalamus connects inferiorly
with pituitary stalk.
o Hypothalamic releasing and inhibitory hormones are secreted into
the Medial Eminence and tuber cinereum – extension of
hypothalamic tissue into pituitary stalk
o These hormones are immediately absorbed into hypoythalamic-
hypophysial portal system and carried directly to sinuses of anterior
pituitary gland
