Pituitary gland

It all starts in the...

Hypothalamus

The pituitary gland can be broken into two lobes:

Anterior and Posterior

What type of tissue makes up the Anterior pituitary gland?

Glandular.

What type of tissue makes up the Posterior Pituitary gland?

Nervous.

What are some other names for the Anterior pituitary gland?

Adenohypophysis, Pars anterior, and Pars distalis.

What are some other names for the Posterior pituitary gland?

Neurohypophysis and Pars nervosa

What hormones does the Anterior lobe secrete?

Corticotropin, Gonadotropins (follitropin and lutropin), Prolactin, Somatotropin, and Thyrotropin.

What is the abbreviation for Corticotropin?

ACTH

What is the abbreviation for Follitropin?

FSH (Follicle-stimulating hormone)

What is the abbreviation for Lutropin?

LH (Luteinizing hormone)

What is the abbreviation for Prolactin?

PRL

What is the abbreviation for Somatotropin?

STH or GH

What is the abbreviation for Thyrotropin?

TSH

Where is the site of action for Corticotropin (ACTH)?

Adrenal cortex.

Where is the site of action for Gonadotropins (FSH and LH)?

Gonads.

Where is the site of action for Prolactin (PRL)?

Mammary glands.

Where the site of actions for Somatotropins (STH/GH)?

General soma

Where is the site of action for Thyrotropin (TSH)?

Thyroid

What biological activity does Corticotropin perform?

Glucocorticoid secretion

What biological activity does Gonadotropins perform?

Germ cell production and steroidogenesis.

What biological activity does Prolactin perform?

Lactation.

What biological activity does Somatotropin perform?

Growth

What biological activity does Thyrotropin perform?

Thyroxin production.

What hormone does the Intermediate lobe secrete?

Intermedin.

What is the site of action of the hormone secreted from the intermediate lobe?

Malanophore (cells of amphibians and reptiles).

What biological activity does Intermedin perform?

Skin color/pigmentation.

What hormone does the Posterior lobe secrete?

Antidiuretic and Oxytocin hormones.

What is the abbreviation for Antidiuretic hormone?

ADH

What is the abbreviation for Oxytocin hormone?

OT

What is the site of action of the Posterior lobe?

Renal tubules, mammary myoepithelium, and uterine myometrium.

What biological activity does the Posterior lobe perform?

Water excretion, milk letdown, and uterine contractions.

What are the target organs of the Anterior Pituitary hormones?

Gona, Adrenal, Thyroid, mammary, uterus, kidneys, etc.

What are the three ways in which pituitary hormones can be grouped into families of structurally related proteins?

Growth hormones and prolactin, thyrotropin, follitropin, lutropin, and neurohypophyseal hormones.

Describe the pituitary hormones grouped into growth hormones and prolactin.

Similar amino acid sequences are structurally similar to placental Lactogen.

Describe the pituitary hormones grouped into Thyrotropin, Follitropin, and Lutropin.

Glycoproteins, composed of alpha and beta chains, and are structurally similar to chorionic gonadotropin.

What are the two Neurohypophyseal hormones?

Oxytocin and Vasopressin; which are structurally related.

Describe Growth hormone.

Polypeptide synthesized by somatotrophs of the pars distills, responsible for general somatic cell growth (anabolic and any cells of a living organism other than the reproductive cells). Basal levels in the plasma range from 1 to 5 ng/mL.

GH levels are increased during...

adolescent growth, spontaneous episodes of GH secretion occur several times over a 24 hour period.

The absence of GH results in...

short stature

The overproduction of GH results in...

during the early postnatal period (gigantism) or during adulthood (acromegaly)

Describe Prolactin.

Polypeptide synthesized by lactotrophs in the pars distills.

What are some of the functions of Prolactin?

Mammary growth and development, lactogenesis, maternal behavior, stimulate corpus luteum growth, differentiation, and function of integumental structures (hair, sebaceous glands, feather development), and testicular function (male rats).

GH and ______ are very similar in structure, both are made up of 191 aa and have an S-S bond,

PRL

What is Thryotropin?

Glycoprotein is synthesized by thyrotrophs in the pars distills.

Glycoproteins are synthesized by...

by gonadotrophs in the pars distills.

Describe the function of male luteinizing hormones.

Binds to Leydig cells, leading to testosterone production.

Describe the function of female luteinizing hormones.

Binds to theca interna cell, leading to androgen production. Acts as the dominant follicle leading to ovulation.

Follicle-stimulating hormone is a...

glycoprotein synthesized by gonadotrophs in the pars distills.

Describe the function of male follicle stimulating hormones.

Binds to Sertoli cells leading to spermatogenesis.

Describe the function of female follicle-stimulating hormones.

Binds to the granulosa cells, leading to folliculogenesis.

Describe the pituitary LH content and FSH content in cattle, respectively.

highest and lowest

Describe the pituitary LH content and FSH content in sheep, respectively.

high and intermediate

Describe the pituitary LH content and FSH content in pigs, respectively.

high and intermediate

Describe the pituitary LH content and FSH content in horses, respectively.

lowest and highest

Glycoprotein hormones from the pars distills include...

TSH, LH, and FSH

Corticotropin is a...

lipotropin polypeptide hormone from the pars distills, the smallest peptide hormone of the pars distills.

Oxytocin and Vasopressin are...

Nonapeptides present in the neurohypophysis are synthesized separately in different neurohypophyseal neurons. Derived from a pro-hormone.

Paraventricular nuclei -->

Oxyphysin --> Oxytocin

Supraoptic nuclei -->

Pressophysin --> Vasopressin