| PITUITARY GLAND Flashcards
Term pituitary is derived from both Latin and Greek which means ___. Initial idea was that
pituitary gland secretes ___. Further studies
identified that it was __ that are released by the pituitary gland
- “to spit mucus”
- mucus
- hormones
aka hypophysis meaning ___ because its structure is situated below the ____
PITUITARY GLAND (HYPOPHYSIS)
- undergrowth
- hypothalamus
A pea shaped organ
aka ____ because it has the capability to regulate the activity of other endocrine gland
Located in a small cavity in the sphenoid bone of the skull called____ surrounded by the dura mater
All pituitary hormones have ____. Its concentration varies depend on the time of the day. ___ meaning time giver. The hormones
released have particular time of the day when it is more active.
2 major lobes: ___ AND ___
PITUITARY GLAND (HYPOPHYSIS)
- “Master Gland”
- sella turcica or Turkish saddle
- circadian rhythms
- Zeitgeber
- Anterior, Posterior
____ is located on the lower portion of the
hypothalamus. Within the hypothalamus, there is ___ which connects the adenohypophysis aka Ant. Pituitary gland to the median eminence and to the hypothalamus. It contains both neural and vascular structures.
- Pineal gland
- Infundibulum or Pituitary stalk
- adenohypophysis aka Ant. Pituitary gland
The_____ below posterior pituitary is
connected to the super optic and paraventricular hypothalamic nuclei. In this vascular network, there is where____
are produced
pituitary stalk
- vasopressin and oxytocin
The “true endocrine gland” bc majority of the
endocrine hormones that regulate other endocrine gland are released by this.
- Regulates the release and production of hormones
- also secretes ____
ANTERIOR PITUITARY GLAND
(ADENOHYPOPHYSIS)
- Endorphins
ANTERIOR PITUITARY GLAND
(ADENOHYPOPHYSIS)
Regulates the release and production of hormones:
1.
2.
3
4
5
Somatotrophs - GH
Lactotrophs - Prolactin
Thyrotrophs - TSH
Gonadotrophs – FSH and LH
Corticotrophs – ACTH
ANTERIOR PITUITARY GLAND
(ADENOHYPOPHYSIS)
Composed of three cell types:
Chromophobe (50%)
Acidophilic (40%)
Basophilic (10%)
regulates the activity of thyroid, adrenals,
and reproductive glands
GH, PRL, TSH, FSH, LH, ACTH
In target gland, the 2 classifications of ant. Pituitary hormones are ___ or _____
tropic or direct effectors.
– this compound is released on a
distant tissue/organ in which it affects the
release of that endocrine gland for another
hormone
Tropic effector
its activity directly affects
the peripheral tissue itself.
Direct effector
Most abundant of all pituitary hormones
TARGET: All cells
Controlled by ___ (promote an increase
production) and ____ (inhibiting hormone which suppresses the release of GH)
- Markedly elevated during sleep (deep sleep)
- Its overall metabolic effect is to metabolize fat
stores while conserving glucose.
- can be direct/indirect
GROWTH HORMONE (SOMATOTROPIN)
- GH-RH
- Somatostatin
The height of an individual/linear growth is a
consequence of several factors, not only by the GH.
These includes:
1.
2
3
Genetic potential
Nutrition
Presence and absence of disease or other
hormonal effects
directly increases the blood glucose lvl by stimulating gluconeogenesis 2 in which energy is utilized from noncarbohydrate sources and reduces insulin sensitivity of cells. Also, it causes _____ specifically lipids stored in adipose tissue
Direct GH
- lipolysis
this is mediated by the insulin-like growth factor (IGF-1) which affects the production of IGF itself. The insulin-like growth factor is
mitogenic and anti-apoptotic
compounds which means it facilitates
cellular cycle/proliferation.
Indirect GH
Other things that stimulate somatotrophin
production include:
Sleep stages III and IV
Stress
Estrogens
Exercise
Fasting/hypoglycaemia –
Amino acids
GHRELIN (from stomach) –
Stimulates GH secretion
Stimulates GH secretion
1.
2
3
4
→ dopamine,
endorphins, serotonin, Norepinephrine
hunger hormone; predominant compound which may be the reason for obesity
GHRELIN (from stomach) –
GH DISORDERS
Idiopathic Growth Hormone Deficiency
Pituitary Adenoma
Children with pituitary dwarfism retain normal
proportions and show no intellectual abnormalities
Acromegaly
One of the possible reasons is due to pituitary
adenoma in which there is a tumor causing
hypopituitarism causing a decrease in the GH
release/secretion.
PITUITARY DWARFISM
GH insufficiency can be caused by a variety of
reasons such as:
1
2
3
4
5
A problem in hypothalamus affecting GHRH
Hypothalamic disease
Disruption/obstruction of portal system of GH
Mutation of GHRH
Diseases involving somatotroph
Condition in which the GH excess occurs during
adulthood
Not necessarily tall, but has deformities or
abnormalities in the extremities. They have spadelike hands (disproportional size) and obvious changes in facial features.
- Clinical significance: Overgrowth of skeleton bc GH release increases in bones and soft tissues
causing:
1
2
3
4
5
ACROMEGALY
- acral enlargement (overgrowth of
extremities)
- Organomegaly
-Hyperhidrosis – excessive sweating
- Joint disease
- myopathy
heart/liver (1 or both) making the individuals prone to conditions such as facial coarsening or soft tissue thickening seen in lips, intestinal
polyposis, protruding jaw called prognathism, impaired glucose tolerance (insulin resistance)
Organomegaly
Hormone release is increased during childhood
Characterized by: Extreme tall stature
Clinical features are the same with acromegaly
(facial features is more common with acromegaly).
In terms of survival, they can survive up to
adulthood but can have CVDs.
GIGANTISM
(potent GH stimulant)
Clonidine
GH DEFICIENCY TESTS
Specimen: preferably ____: complete rest
30 minutes before blood collection
fasting serum
GH DEFICIENCY TESTS
A. Insulin Tolerance Test
B. Arginine Stimulation Test
gold standard & confirmatory test for GH DEFICIENCY TESTS
Insulin Tolerance Test
2nd confirmatory test
Failure of GH to rise > 5ng/ml (adults) and >10
ng/ml (child) is abnormal
Arginine Stimulation Test
determine the level of Somatomedin C or
insulin- like growth factor 1 (IGF- 1)
IGF-1 is increased in patients with it.
IGF-1 is low in____
Screening Test for Acromegaly
- GH deficiency
Glucose Suppression Test – OGTT (75g
glucose) or 100g (from Bishop)
Blood is collected every after 30 minutes for 2
hours; fasting sample is required.
In Bishop’s, GH is measured at time:
0
60 mins – 1 st hr
120 mins – 2nd hr
If the GH fails to decline <1 ng/ml, it is
___
A normal response for this test is a suppression of GH <1ng/ml
High glucose conc. should have been
able to suppress the GH release and
must be undetectable for normal
individuals.
Confirmatory Test for Acromegaly
- acromegaly
Important markers in diagnosing fertility and
menstrual cycle disorders.
present in the blood of male and female at all ages.
elevation of ___ is a clue in the diagnosis of
premature menopause
Increase of it after menopause is due to lack of ___
Both acts synergistically to promote ovulation and for the secretion of ___ and ___
GONADOTROPINS (Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH))
-FSH
- estrogen
- androgens (androstenedione)
- progesterone
Luteinizing Hormone aka ___ or ___
Interstitial cellstimulating hormone
(ICSH) or Lutropin
Follicle Stimulating Hormone aka ___
Follitropin
In male, FSH aids in
___
spermatogenesis
In male, Stimulates the development & functional activity of Leydig cells to produce ___
testosterone
In Female, To stimulate growth
and maturation of ovarian follicles
Stimulate _____ secretion (estradiol)
Promote via estrogen the endometrial
changes on the 1st portion of menstrual
cycle called _____
Follicle Stimulating Hormone
-estrogen
-proliferative/follicular phase
In female, it acts on theca cells to cause the
synthesis of ____, __, and ___
Promoting and maintaining the 2nd
portion of menstrual cycle ____
Assists in formation of corpus luteum
necessary for ovulation and final follicular growth
Luteinizing Hormone
- androgens, estrogens, progesterone.
- (luteal phase)
lack of FSH and LH in both male and female
inability to conceive after 1 year of unprotected intercourse
INFERTILITY
Aka: __
- Main stimulus for the uptake of iodide by the thyroid gland done via the sodium iodide transporter mechanism
- Significant for organification/reduction of
iodine
Stimulates thyroid hormone synthesis of ___ and ____
Stimulates growth and vascularity of thyroid gland
Stimulates growth of follicular cells of___
Promotes coupling of tyrosines and promotes
proteolytic release of thyroid hormone
Blood levels may contribute in the evaluation of infertility
TSH (THYROID STIMULATING HORMONE)
- Thyrotropin
-Thyroxine (T4) and Triiodothyronine (T3)
- thyroid 4
TSH secretion is suppressed by:
1
2
3
Thyroid hormone
Glucocorticoids
Estrogens
Other compounds affecting TSH release
1
2
3
1 Acute inflammatory cytokines such as IL1, IL6,
TNF - stimulate ACTH release but suppress
TRH and TSH
2 Endorphins, serotonin & dopamine - suppress
TSH
3 Norepinephrine - stimulates TSH release
derivative of POMC (propiomelanocortin)
acts on adrencal cortex causing stimulation of its growth and secretion of corticosteroids (cortisol).
- Produced in response to low serum cortisol;
regulator of adrenal androgen synthesis
Highest level is between 6-8AM; lowest level is
between 6-11PM
Specimen for testing should not be allowed to have contact with glass bc it is easily oxidized and readily absorbs glass
Specimen Requirement: Blood should be collected into _____. It must be immediately placed in ice and centrifuge at __(must be maintained).
o Some lab uses stabilizers like ___
Increased Levels: ___, ____ and ___
ACTH (ADRENOCORTICOTROPIC HORMONE)
- prechilled polysterene (plastic) tubes containing EDTA
- 4oC temp
-protease inhibitors
- Addison’s disease, ectopic
tumors, after protein-rich meals
hypersecretion of ACTH
- leads to bilateral adrenal hyperplasia and cortisol overproduction
CUSHING’S DISEASE
Signs & symptoms:
fullness or rounding of face (moon facie)
distinct: buffalo hump – added fat at the back
of the neck
prone to bruises
abdominal striae (stretch marks)
Obesity!!!
Plethora – reddening of cheeks
CUSHING’S DISEASE
Directly a problem involving the adrenal gland
may be caused by secondary (ACTH) or tertiary (CRH) adrenal insufficiency
hyposecretion of glucocorticoids and aldosterone
ADDISON’S DISEASE
Signs & symptoms
extreme fatigue
leads to weight loss and decreased appetite
hyperpigmentation
low BP
craves for increased intake of Na;
hypoglycemia
prone to muscle joint paints
irritability and behavioral effect (as if there’s
mental illness)
hair loss
sexual dysfunction
ADDISON’S DISEASE
Pituitary lactogenic hormone
In terms of structure, it is related to GH and human placental lactogen
Stress Hormone
Functions in the initiation and maintenance of
lactation (stimulated by breastfeeding) and breast tissue development
release can also be stimulated in cases of:___ and ___
Also acts in conjunction with__ and ____
Major Inhibitory Factor: ___
Highest level: 4AM-8AM; 8PM-10PM
Increased Level: ___, ___ ___ ___
Aldomet, phenothiazines, reserpine, TCA (tricycline anti-depressants), some anti-psychotic drugs =___ ; antagonize the effects of dopamine
PROLACTIN
- Chest wall disease and stress
- estrogen & progesterone
- Dopamine
- Menstrual irregularity, infertility,
amenorrhea and galactorrhea
- HYPERPROLACTINEMIA
Post-partum hypopituitarism due to haemorrhage or shock in a pregnant female at the time of delivery
a type of pituitary ischemia
SHEEHAN’S SYNDROME
inappropriate production of breast milk due to
hypersecretion of PRL
Symptoms: irregular menstruation, menopausal symptoms, milk discharges, difficulty in getting erection, breast tenderness and enlargement
GALACTORRHEA
Shows that the px have normal prolactin.
Occurs for those who have been pregnant for
several times
No significant pathologic implication
Idiopathic Galactorrhea
absence of menstrual cycle in females due to
hypersecretion of PRL
AMENORRHEA
inability to attain penile erection in males due to
hypersecretion of PRL
IMPOTENCE
derived from the brain neuroectodermis
Capable of releasing the hormone but not capable of producing it.
Hormones produced by it are controlled by the CNS
POSTERIOR PITUITARY (NEUROHYPOPHYSIS)
POSTERIOR PITUITARY (NEUROHYPOPHYSIS)
2 Hormones:
- Oxytocin
- Antidiuretic Hormone (ADH)
aka ___
Acts on the distal convoluted tubule and collecting tubule of the kidneys.
Decreases production of urine; facilitates H2O
reabsorption
____ is the principal regulator of ADH secretion
Increases ____ (Potent pressor agent)
___ inhibits release of it
This explains why every time a person
drinks alcoholic drinks it causes an
increased urge to urinate
Diagnostic Test: _____
Urine osmolality does not rise >300 mOsm/kg
ANTIDIURETIC HORMONE
- Arginine vasopressin
-Osmolality of blood
- blood pressure
- Ethanol
- Overnight water deprivation Test
(concentration test)
in mellitus - ___
in insipidus -
glucose
ADH
Deficient in ADH
Result in polyuria
DIABETES INSIPIDUS
CLINICAL PICTURE DIABETES INSIPIDUS
1
2
3
4
- Normoglycemia
- Polyuria with low S.G
- Polydipsia
- Polyphagia – occasional
2 TYPES OF DIABETES INSIPIDUS
True Diabetes Insipidus
Nephrogenic Diabetes Insipidus
Deficient ADH with normal ADH receptor.
True if the problem is directly with ADH.
This may be due to hypothalamic/pituitary
disease
True Diabetes Insipidus
Normal ADH with normal ADH receptor
but with renal resistance to ADH action
Kidney is not responding
Nephrogenic Diabetes Insipidus
Normal ADH with normal ADH receptor
- Failure of the kidneys to respond to normal/
elevated ADH levels
- Urine output: >2.5 L
- Treatment___
Diagnostic test: __
Nephrogenic DiabeteS Insipidus
- Desmopressin (dDAVP)
- Water deprivationtest
Caused by distractive hypothalamic lesion or
infundibular lesion
Deficiency of ADH with normal ADH receptor,
due to hypothalamic or pituitary disease
Failure of the pituitary gland to secrete ADH
Large volume of urine is excreted (3-20L/day)
True Diabetes Insipidus
There is pathologic ADH excess which may be caused by different conditions. This causes H2O retention
→ causing reduced plasma osmolality and
hyponatremia and eventually leading to edema
SIADH (Syndrome of Inappropriate ADH) secretion
autonomous sustained production of AVP in the
absence of known stimuli for its release
Causes: stress, malignancy (leukemia), pulmonary disorders (hypoxia, pneumonia, and emphysema) drug therapies (anticonvulsants, anti-neoplastic drugs, and ACE inhibitors), CNS diseases (brain tumor, meningitis, encephalitis or CNS abscess), prolonged seizures or psychiatric diseases
decreased urine volume, increased sodium
concentration and urine osmolality
Ectopic tumor production of ADH: small cell
carcinoma of the lung
Diagnosis: ___
Syndrome of Inappropriate ADH Secretion (SIADH)
- Water load test
Very similar in ADH composition
- ___ secreted by the magnocellular
neurons of hypothalamus, secreted in association with a carrier protein
The gene is responsible for the release of 2 proteins: ___ and ___
Unique bc its secretion responds to positive
feedback loop mechanism bc the circulating level of it perpetuates further hormone secretion
Stimulates contraction of gravid uterus (____) and muscle contraction (during delivery and
lactation)
Released in response to neutral stimulation of
receptors in birth canal, uterus and breast touch
receptors.
Synthetic preparations of oxytocin (such as pitocin) are used to increase weak uterine contractions during labor and aid in lactation
OXYTOCIN
- Nanopeptide
- oxytocin and neurophysin 1
- Fergusson reflex
OXYTOCIN Actions
UTERUS at PARTURITION
BREAST during LACTATION
UTERUS at PARTURITION
MYOMETRIAL cells contract
Delivery of baby
BREAST during LACTATION
MYOEPITHELIAL cells contract
Milk ejection
