Transcript 17. Pituitary and Adrenal Glands

The Pituitary Gland
The hypothalamus significantly influences the pituitary gland
Posterior
pituitary
Hypothalamic releasing
and inhibiting hormones
are delivered to the
anterior pituitary
The hypothalamus makes
and releases the hormones
of the posterior pituitary
Pituitary (Hypophysis)
• Posterior Pituitary – “neurohypophysis”
• Anterior Pituitary – “adenohypophysis”
 Oxytocin
 
 Antidiuretic Hormone (ADH)
• Anterior Pituitary – synthesizes 6 hormones.
 Growth Hormone (hGH)
(also called Somatotropin)
 Adrenocorticotropic Hormone (ACTH)
(also called corticotropin)
 Thyroid Stimulating Hormone (TSH)


 Follicle Stimulating Hormone (FSH)
 Luteinizing Hormone (LH)
 Prolactin (PRL)
 hGH – is the primary hormone that regulates overall body
growth, also important in general metabolism.
 ACTH – stimulates cortisol secretion from the adrenal
cortex (the stress hormone!). Also promotes
growth of adrenal cortex.
 TSH – stimulates secretion of thyroid hormone and the
growth of the thyroid gland. Important regulator of
metabolic activity in the body.
 FSH – a) in females: stimulates growth and development of
ovarian follicles, and promotes estrogen secretion.
b) in males: it is required for sperm production.
 LH – a) in females: responsible for ovulation and for
luteinization. Regulates estrogen and progesterone.
b) in males: stimulates interstitial cells (in testes)
to secrete testosterone.
* called interstitial cell stimulating hormone (ICSH)
 PRL – enhances breast development and milk production
in females.
Pituitary Gland has enormous impact on entire Body.
7ft 7in tall, died at age 22.
Adrenal disorders in Females:
• Hirsutism (male hair)
• Oligomenorrhea (infrequent menstruation)
• Deepening of voice
• Hypertrophy of clitoris (resemble penis)
Thyroid Goiter.
Negative Feedback Loop of
Hypothalmic-Adenohypophysis
and the Thyroid Gland
Normal Growth
• Growth hormone and other hormones
• An adequate diet
• Absence of stress
• Genetics
Acetyl CoA
Hydroxymethyl Glutaric Acid (HMG-CoA)
Statin = HMG-CoA reductase inhibitors
Mevolaonate
Mevolaonate Pyrophosphate
Isopentenyl Pyrophosphate
Geranyl Pyrophosphate
Famesyl Pyrophosphate
Squalene
Ubiquinone
(CoQ10)
Cholesterol
Dolichol
Cholesterol
Vitamin D
Cortisone
Glucocorticoids
Mineralcorticoids
Steroid Hormones
(testosterone, estrogen,
progesterone)
Bile Salts
Wow, what a “Life Saver”.
Growth Hormone
• Severe hGH deficiency leads to dwarfism
• Over secretion of hGH in children leads to
gigantism
• Over secretion of
hGH in adults leads
to acromegaly
Pathway of Growth Hormone Control
The Hypothalamus-Pituitary-Adrenal Axis
(HPA)
The
Cortisol
Connection
CRH = Corticotropin Releasing Hormone
ACTH = Adrenocorticotropic Hormone
The many functions of
cortisol in the body:
Cortisol
• Promotes gluconeogenesis
• Breakdown of skeletal muscle proteins
• Enhances lipolysis (prevents glucose use)
• Permissive – needed for NE vasoconstriction
• Suppresses the immune system
• Response to stressors – protective?
Circadian Rhythm of Cortisol Secretion
Hyper-Cortisolism
• Adrenal tumor that ↑ cortisol
• Pituitary tumor that ↑ ACTH
e.g., Cushing’s Disease
↑ glucose and ↓ protein
Loss of muscle mass
Characteristic fat deposits
Normal
Hyper-Cortisolism
"Moon" face, "Buffalo" hump
Protruding abdomen
High Blood Pressure
Weakness, Acne, Backache
Excessive thirst & urination
Easy Bruising
Hypo-Cortisolism
• Under secretion of adrenal steroid hormones
• Autoimmune destruction of adrenal cortex
e.g. Addison’s Disease
↓ glucose (hypoglycemia)
Poor response to stress
Lack of vasoconstriction (permissive NE action)
Symptoms and Clinical Signs
Fatigue and muscle weakness.
Low Blood Pressure (Orthostatic Hypotension).
Headache, sweating, joint and muscle pains.
Increased Melanocyte-Stimulating Hormone (MSH).
Growth Hormone