8 Hormones

Quiz Thursday 9/15

Oxytocin Posterior Pituitary Hormone (Peptide, mostly from neurons in paraventricular

nucleus of hypothalamus)

Stimulated by impulses from hypothalamic neurons in response to stretching of the uterine cervix

or suckling of infant at breast.

Inhibited by lack of appropriate

neural stimul

Uterus: simulates uterine contractions, initiates labor.

Breast: initiates milk ejection

Effects of Hyposecretion and Hypersecretion: Unknown

Antidiuretic hormone (ADH) or vasopressin  Posterior Pituitary Hormone(Peptide, mostly from neurons in supraoptic

nucleus of hypothalamus

Stimulated by impulses from hypothalamic neurons in response to increased blood solute concentration or decreased blood volume; also stimulated by pain, some drugs, low blood pressure

Inhibited by adequate hydration

of the body and by alcohol

Kidneys: stimulate kidney tubule

cells to reabsorb water

Effects of Hyposecretion: Diabetes insipidus

Effects of Hypersecretion : Syndrome of inappropriate ADH secretion (SIADH)

Growth hormone (GH) Anterior Pituitary Hormone (Protein, somatotropic cells)

Stimulated by GHRH* release, which is triggered by low blood levels of GH as well as by a number of secondary triggers including deep sleep, hypoglycemia, increases in blood levels of amino acids, low levels of fatty acids, exercise, and other types of stressors 

Inhibited by feedback inhibition exerted by GH and insulin-like growth factors (IGFs), and by hyperglycemia, hyperlipidemia, obesity, and emotional deprivation via either increased GHIH*

(somatostatin) or decreased

GHRH* release

Liver, muscle, bone, cartilage, and

other tissues: anabolic hormone; stimulates somatic growth; mobilizes fats; spares glucose 

Growth-promoting effects

mediated indirectly by IGFs 

Effects of Hyposecretion: Pituitary dwarfism in children

Effects of Hypersecretion: Gigantism in children; acromegaly in adults

Thyroid-stimulating hormone (TSH) Anterior Pituitary Hormone (Glycoprotein, thyrotropic cells

Stimulated by TRH* and in infants indirectly by cold temperature 

Inhibited by feedback inhibition exerted by thyroid hormones on anterior pituitary and

hypothalamus and by GHIH

Thyroid gland: stimulates thyroid gland to release thyroid

hormone

Effects of Hyposecretion: Hyperthyroidism; may cause mixedema

Effects of Hypersecretion: Hyperthyroidism; effects similar to those of graves disease, in which antibodies mimic TSH

Adrenocorticotropic hormone (ACTH) Anterior Pituitary Hormone (Peptide, corticotropic cells)

Stimulated by CRH*; stimuli that increase CRH release include fever, hypoglycemia, and other stressors 

Inhibited by feedback inhibition exerted by glucocorticoid

Adrenal cortex: promotes release of glucocorticoids and androgens (mineralocorticoids to a lesser extent)

Effects of Hyposecretion:  Rare

Effects of Hypersecretion: Cushing's Disease

Follicle-stimulating hormone (FSH) Anterior Pituitary Hormone(Glycoprotein, gonadotropic cells)

Stimulated by GnRH* 

Inhibited by feedback inhibition exerted by inhibin, and estrogens in females and testosterone in males

Ovaries and testes: in females, stimulates ovarian follicle maturation and production of estrogens; in males, stimulates sperm production.

Effects of Hyposecretion: Failure of sexual maturiation 

Effects of Hypersecretion: No important effects

Luteinizing hormone (LH) Anterior Pituitary Hormone (Glycoprotein, gonadotropic cells)

Stimulated by GnRH* 

Inhibited by feedback inhibition exerted by estrogens and progesterone in females and testosterone in males.

Ovaries and testes: in females, triggers ovulation and stimulates ovarian production of estrogens and progesterone; in males, promotes testosterone production

Effects of Hyposecretion and Hypersecretion: As for FSH

Prolactin (PRL)Anterior Pituitary Hormone (Protein, prolactin cells)

Simulated by decreased PIH release enhanced by estrogen birth control pills, breast-feeding, and dopamine-blocking drugs.

Inhibited by PIH* (dopamine)

Breast secretory tissue: promotes lactation 

Effects of Hyposecretion: Poor milk production in nursing women.

Effects of Hypersecretion: Inappropriate milk production (galactosehea) cessation of menses in females; impotence in males.