Summary H76 - SV Guyton and Hall

Guyton and Hall
CHAPTER 76 – Pituitary Hormones and Their Control by the Hypothalamus

The pituitary gland is also called the hypophysis. It is connected to the
hypothalamus by the pituitary (hypophysial) stalk. The pituitary gland
is divisible into two portions:
 The anterior pituitary (adenohypophysis)
 The posterior pituitary (neurohypophysis)

Between these portions is a small avascular zone called the pars
intermedia.

The anterior pituitary gland contains several different cell types which
synthesize and secrete hormones:

CELL TYPE: HORMONES THEY PHYSIOLOGICAL ACTION OF
PRODUCE: THE HORMONE:
SOMATOTROPES Human growth hormone Promotes growth of the
(hGH) entire body by affecting
protein formation, cell
multiplication and cell
differentiation
CORTICOTROPES Adrenocorticotropin (ACTH) Controls secretion of
adrenocortical hormones
which affect metabolism of
glucose proteins and fats
THYROTROPES Thyroid-stimulating Controls secretion rate of
hormone (TSH) thyroxine and
triiodothyronine by the
thyroid gland
GONADOTROPES Gonadotropic hormones: Control growth of the
ovaries and testes, as well
 Luteinizing hormone as their hormonal and
(LH) reproductive activities.
 Follicle-stimulating
hormone (FSH)

LACTOTROPES Prolactin (PRL) Promotes mammary gland
development and milk
production.

The posterior pituitary hormones are synthesized by cell bodies in the hypothalamus. The
bodies of the cells are not located in the pituitary gland but are large neurons, called
magnocellular neurons. Hormones secreted by the posterior pituitary are:
 Antidiuretic hormone: controls rate of water excretion into the urine
 Oxytocin: helps express milk from the glands of the breasts to the nipples during
suckling and helps in the delivery of the baby at the end of gestation.