[M6 GROUP 1] Hypothalamic and Pituitary Function Flashcards by Marlo Roque

PITUITARY is aka

master gland

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aka “master gland”

PITUITARY

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PITUITARY is derived from both ___ and ___ which means to “____”

Latin,
Greek,
spit mucus

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It secrete hormones that regulate the other endocrine glands

PITUITARY

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PITUITARY also referred as “___”, from Greek meaning “____”

hypophysis,
undergrowth

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hypophysis means

undergrowth

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Reflection of dura

Diaphragma sella

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It separates superior portion of the pituitary from the hypothalamus

Diaphragma sella

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Diaphragma sella is Penetrated by ____

infundibulum

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Connects adenohypophysis to the median eminence and
hypothalamus

Infundibulum

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Infundibulum connects ____ to the median ___ and
_____

adenohypophysis;
eminence;
hypothalamus

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WHAT ARE THE 4 FEATURES THAT DISTINGUISH THE FUNCTION OF PITUITARY

Feedback loops
Pulsatile secretions
Diurnal rhythms
Environmental or external modification of its performance

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What are the three distinct parts of the pituitary:

Anterior pituitary
Intermediate lobe
Posterior pituitary

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Anterior pituitary is aka

adenohypophysis

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Anterior pituitary or adenohypophysis receives ____ of the ____ and ____ via the _____

80-90%;
blood supply;
hypothalamic factors;
hypothalamic–hypophyseal portal system

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Receives 80-90% of the blood supply and hypothalamic factors via
the hypothalamic–hypophyseal portal system

Anterior pituitary or adenohypophysis

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Intermediate lobe is aka

pars intermedalis

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Poorly developed in humans and has little functional capacity

Intermediate lobe or pars intermedalis

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Posterior pituitary is aka

neurohypophysis

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Posterior pituitary or neurohypophysis is Responsible for storage and release of ___ and ___

oxytocin
vasopressin

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Responsible for storage and release of oxytocin and vasopressin

Posterior pituitary or neurohypophysis

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Posterior pituitary or neurohypophysis is Connected to the ___ and ____ hypothalamic nuclei

supraoptic;
paraventricular

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Connected to the supraoptic and paraventricular hypothalamic nuclei

Posterior pituitary or neurohypophysis

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What are the different Anterior Pituitary Cell Types

Lactotrophs
Somatotrophs
Thyrotrophs
Corticotrophs
Gonadotrophs
Follicle-stimulating hormone

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prolactin-secreting cells

Lactotrophs

growth hormone [GH]-secreting cells

Somatotrophs

(thyroid-stimulating hormone [TSH]-secreting cells

Thyrotrophs

adrenocorticotropin hormone [ACTH]-secreting cells

Corticotrophs

luteinizing hormone

Gonadotrophs

[FSH]-secreting cells

Follicle-stimulating hormone

WHAT ARE THE FUNCTIONAL ASPECTS OF THE HYPOTHALAMIC-HYPOPHYSEAL UNIT

Endocrine Feedback Loop Pulsatility Cyclic nature of Hormone Secretion

An example of Endocrine Feedback Loop

Hypothalamic-Pituitary-Thyroidal Axis

Can be partially inhibited by adrenal steroids and cytokines

Hypothalamic-Pituitary-Thyroidal Axis

Hypothalamic-Pituitary-Thyroidal Axis Can be partially inhibited by ____ and ___

adrenal steroids cytokines

TRH means

Thyrotropin-releasing hormone

Thyrotropin-releasing hormone is produced by

hypothalamus

It is a Hypophysiotropic hormone

Thyrotropin-releasing hormone (TRH)

Directs the thyrotrophs

Thyrotropin-releasing hormone (TRH)

TSH-producing cells

thyrotrophs

Thyrotropin-releasing hormone (TRH) secretes?

Thyroid Stimulating Hormone (TSH)

stimulates several steps in the thyroid that are critical in the production and release of thyroid hormone (thyroxine)

Thyroid Stimulating Hormone

The one that suppress TRH and TSH production

Thyroxine

feedback of thyroxine at the level of the pituitary

Short feedback loop

Short feedback loop is the feedback of thyroxine at the level of the ___

pituitary

feedback at the level of the hypothalamus

Long feedback loop

Feedback between the pituitary and hypothalamus (when present)

Ultrashort feedback loop

Regulated by neural modulation

Pulsatility

Pulsatility is Regulated by ____

neural modulation

→ Specific for each hypothalamic-pituitary-end-organ unit

Pulsatility

Median interpulse interval for LH

Pulsatility

Pulsatility: Normal Male: ___

55 minutes

Pulsatility: Average LH peak duration: _____

40 minutes

Regulatory hypothalamic hormone

Gonadotropin-Releasing Hormone (GnRH)

Its pulse frequency has profound effects on LH secretion profiles

Gonadotropin-Releasing Hormone (GnRH)

Gonadotropin-Releasing Hormone (GnRH) Increased: reduces ___

gonadotrope secretory response

Gonadotropin-Releasing Hormone (GnRH) Decreased: increases the ____

amplitude of the subsequent LH pulse

Regulated by nervous system through external signals

Cyclic nature of Hormone Secretion

It means “time giver”

“Zeitgeber”

Process of entertaining or synchronizing theses external cues into the function of internal biologic clocks

“Zeitgeber”

Cyclic nature of Hormone Secretion

Cyclic nature of Hormone Secretion is Typified by ___ or ___ secretion

ACTH; TSH

Cyclic nature of Hormone Secretion: Typified by ACTH or TSH secretion o Lowest: _____ o Peak: _____

11:00 pm and 3:00 am 6:00 am to 9:00 am

Nocturnal Levels of TSH is ____ the ____ levels

twice daytime

Nocturnal Levels of TSH is Increased due to increased ___

pulse amplitude

Actions of Hypothalamic hormones: ● TRH stimulates secretion of ___ and ____ ● GnRH stimulates ____ and ___ ● Somatostatin (SS) inhibits ___ and ___ release ● Vasopressin (ADH) stimulate ___ secretion

TSH ; prolactin LH ; FSH GH ; TSH ACTH

What are the Actions of Hypothalamic hormones:

● TRH stimulates secretion of TSH and prolactin ● GnRH stimulates LH and FSH ● Somatostatin (SS) inhibits GH and TSH release ● Vasopressin (ADH) stimulate ACTH secretion

What are the different Hypophysiotropic hormones

TRH GnRH CRH GHRH Somatostatin Dopamine

HYPOPHYSIOTROPIC HORMONES: What is the structure of TRH

3 amino acids

HYPOPHYSIOTROPIC HORMONES: What is the action of TRH

Release TSH and prolactin

HYPOPHYSIOTROPIC HORMONES: What is the structure of GnRH

10 amino acids

HYPOPHYSIOTROPIC HORMONES: What is the action of GnRH

Releases LH and FSH

HYPOPHYSIOTROPIC HORMONES: What is the structure of CRH

41 a.a

HYPOPHYSIOTROPIC HORMONES: What is the action of CRH

releases ACTH

HYPOPHYSIOTROPIC HORMONES: What is the structure of GHRH

44 a.a

HYPOPHYSIOTROPIC HORMONES: What is the action of GHRH

releases growth hormone

HYPOPHYSIOTROPIC HORMONES: What is the structure of somatostatin

14 and 28 a.a

HYPOPHYSIOTROPIC HORMONES: What is the action of somatostatin

Inhibits GH and TSH release (additional effects on gut and pancreatic function

HYPOPHYSIOTROPIC HORMONES: What is the structure of dopamine

1 a.a

HYPOPHYSIOTROPIC HORMONES: What is the action of dopamine

inhibits prolactin release

prolactin inhibitory factor

dopamine

ANTERIOR PITUITARY HORMONES is characterized as (2)

Direct effectors Tropic

classification of anterior pituitary hormone that act directly on peripheral tissues

Direct effectors

Example of Direct effectors

classification of anterior pituitary hormone that is specific for another endocrine gland

Tropic

WHAT ARE THE DIFF TROPIC HORMONES

LH FSH TSH ACTH

Tropic hormone that directs testosterone production from men and women

LH – directs ___ production from: ✓ Men: ___ ✓ Women: ___

testosterone; Leydig cells; Ovulation

FSH is responsible for: ✓ Men: ____ ✓ Women: ___

Spermatogenesis; Ovarian recruitment and Ovulation

TROPIC HORMONES that directs thyroid hormone production

TSH

TROPIC HORMONES that regulates adrenal steroidogenesis

ACTH

What are the diff anterior pituitary hormone

LH FSH TSH ACTH GH PRL

What is/are the anterior pituitary hormone that targets the gonad (tropic) gland

LH FSH

anterior pituitary hormone with dimeric glycoprotein structure

LH FSH TSH

What is/are the anterior pituitary hormone that targets THYROID (TROPIC) GLAND

TSH

What is/are the anterior pituitary hormone that targets adrenal (tropic) gland

ACTH

What is/are the anterior pituitary hormone that targets Multiple (direct effector) gland

What is/are the anterior pituitary hormone that targets breast (direct effector) gland

Prolactin

anterior pituitary hormone with SINGLE PEPTIDE DERIVED FROM POMC structure

ACTH

anterior pituitary hormone with SINGLE PEPTIDE

GH PRL

LH Feedback hormone: ____

Sex steroids

FSH Feedback hormone: ____

Inhibin

TSH Feedback hormone: ____

Thyroid hormones

ACTH Feedback hormone: ____

cortisol

GH Feedback hormone: ____

IGF-1

PRL Feedback hormone: ____

Unknown

____ of people harbor clinically silent ___

20% pituitary adenomas

____ of ___ individuals have ____ observed under ___

10% - 30%; normal; pituitary tumors; MRI examinations

____ of the lesions removed from carefully selected patients who have undergone ____ surgery are ____

91%; transsphenoidal ; pituitary tumors

Most common Pituitary tumor

prolactin secreting pituitary tumors

Have an MIB-1 proliferative index greater than 3%

Atypical Pituitary Tumors

monoclonal antibody used to detect Ki-67

MIB-1

- a marker of cell proliferation

Ki-67

Excessive p53 immunoreactivity

Atypical Pituitary Tumors

Atypical Pituitary Tumors has Excessive ____

p53 immunoreactivity

Increased mitotic activity

Atypical Pituitary Tumors

Macroadenomas

Atypical Pituitary Tumors

Show invasion into surrounding structures like the cavernous sinuses

Atypical Pituitary Tumors

● Seen during puberty and pregnancy

PHYSIOLOGIC ENLARGEMEN (OF PITUITARY TUMORS)

PHYSIOLOGIC ENLARGEMEN (OF PITUITARY TUMORS) IS SEEN DURING ___ AND ___ DUE TO ____

puberty; pregnancy; lactotroph hyperplasia

seen in long standing primary thyroidal failure

Thyrotroph and lactotroph hyperplasia

Gonadal failure

Gonadotroph hyperplasia

GROWTH HORMONE IS AKA

Somatotropin

Structurally related to prolactin and human placental lactogen

GROWTH HORMONE

GROWTH HORMONE IS Structurally related to ___ and ___

prolactin; human placental lactogen

GROWTH HORMONE is produced by the ___ specifically the ___ (____)

pituitary gland; somatotrophs; pituitary cells

Produced by the pituitary gland specifically the somatotrophs (pituitary cells)

GROWTH HORMONE

Release of this hormone is stimulated by the growth hormone-releasing hormone (GHRH)

GROWTH HORMONE

GROWTH HORMONE Release is stimulated by the ____

growth hormone-releasing hormone (GHRH)

enteric hormone that plays an important role in nutrient sensing, appetite, and in glucose regulation leading to stimulation of GH secretion

Ghrelin

This hormone is secreted in pulses

GH is secreted in ___

pulses

GROWTH HORMONE: Between pulses, level of GH may be ____ leading to clinical evaluation of ____ based on a ____, ____

undetectable; GH deficiency; single; challenging measurement

Other modifiers of Growth hormone secretion that STIMULATES GH Secretion

Sleep Exercise Physiologic stress Amino acids Hypoglycemia Sex steroids α-Agonists β-Blockers

Other modifiers of Growth hormone secretion that INHIBITS GH Secretion

Glucose loading β-Agonists α-Blockers Emotional/psychogenic stress Nutritional deficiencies Insulin deficiency Thyroxine deficiency

EXAMPLE of amino acids used to STIMULATE GH secretions

Arginine

EXAMPLE of α-Agonists used to STIMULATE GH secretions

norepinephrine

EXAMPLE of β-blockers used to STIMULATE GH secretions

propranolol

EXAMPLE of β-Agonists used to INHIBIT GH secretions

epinephrine

EXAMPLE of α-Blockers used to INHIBIT GH secretions

phentolamine

Amphibolic hormone

GH is ____ hormone

Amphibolic hormone

anabolic effects of the action of GH (Amphibolic hormone) Reflected by enhanced ____ in tissues which is translated into ___ and phosphate retention

protein synthesis; positive nitrogen balance; phosphate retention

ACTIONS OF GH: Major effect is permitting the effective ___ of an individual from ___ to ____ (without experiencing a ___ of _____)

transition ; fed state ; fasting state ; shortage ; substrates

Major effect is permitting the effective transition of an individual from fed state to fasting state

ACTIONS OF GH

ACTIONS OF GH Directly ___ the effect of ___ on ___

antagonizes ; insulin ; glucose metabolism

Directly antagonizes the effect of insulin on glucose metabolism

ACTIONS OF GH

ACTIONS OF GH: Promotes ___

hepatic gluconeogenesis

Promotes hepatic gluconeogenesis

ACTIONS OF GH

ACTIONS OF GH: Stimulates ___

lipolysis

Indirect effects of ___ is mediated by ____ (former name) that is now known as ____

GH ; somatomedins ; Insulin-like Growth Factor (IGF)

What are the Indirect effects of GH

→ Hypoglycemia → Hyperinsulinemia → Stimulation of IGF-1 production → Inhibition of neoplastic cell proliferation → Higher rates of colorectal cancer risk

Indirect effects of GH that amplifies GH levels

Stimulation of IGF-1 production

___ and ___ levels are measured through ____. Elevated levels of these two are consistent with sustained ___

IGF-I ; IGFBP-3 ; assays ; excess of GH

Increased IGF-I is associated with ___

Hepatoma

Low IGF-I is associated with ___ (3)

✓ Poorly controlled diabetes ✓ Malnutrition ✓ Chronic illnesses

Individuals with active acromegaly shows ___ levels of IGFBP-3

ABNORMAL

Abnormal levels of IGFBP-3 is seen in individuals with __

active acromegaly

Definitive testing for determination of autonomous production of GH

Oral glucose loading

Oral glucose loading is Performed after ____

overnight fasting

Performed after overnight fasting

Oral glucose loading

In Oral glucose loading, Px is given ___

100g oral glucose load

GH is measured at time zero, 60, and 120 minutes after glucose ingestion

Oral glucose loading

In Oral glucose loading, GH is then measured at time ___, ___, and ___ ___ after ____

zero ; 60 ; 120 ; minutes ; glucose ingestion

Result of Oral glucose loading; Undetectable GH = ___

Normal

Result of Oral glucose loading; Detectable GH = ___

Acromegaly

Insulin-like Growth Factor (IGF) TESTING: Gold standard: ___

: Insulin-induced hypoglycemia

Most widely used for testing GH

Combination infusions of GHRH and L-arginine or infusion of L-arginine coupled with oral L-DOPA

: Most widely used for testing GH Combination infusions of ____ and ____ or ___ of L-arginine coupled with oral ____

GHRH ; L-arginine ; infusion ; L-DOPA

What is the GH levels of patient who is not GH deficient

>3-5 ng/mL

Results from pathologic or autonomous GH excess and pituitary tumor

ACROMEGALY

ACROMEGALY Results from pathologic or autonomous _________and _________

GH excess pituitary tumor

tumors causing acromegaly are results of the ectopic production of _________

GHRH (Growth Hormone-Releasing Hormone)

Diseases Associated with Acromegaly

Gigantism

Patient with GH-producing tumors may develops

Gigantism

FEATURES OF GIGANTISM ✓ progressive enlargement of the ____________ ✓ growth of ________, including the _______ and bones of the ____ ✓ significant gaps between their _____ ✓ overgrowth of the _____________ or the ______ can produce a debilitating form of ________.

hands and feet facial bones, mandible, skull. teeth ends of long bones, spine, arthritis

Enumerate the clinical features of gigantism

● Overt Diabetes or glucose intolerance ● Hypertension ● Accelerated atherosclerosis ● Proximal muscle weakness, resulting from acquired myopathy ● Sleep apnea is common ● Organomegaly, especially thyromegaly, is common. ● Hyperthyroidism

Symptoms of Acromegaly

● Excessive sweating or heat intolerance

SYMPTOMS OF ACROMEGALY If left untreated, acromegaly increases risk of the following:

✓ heart disease, resulting from the combination of hypertension ✓ coronary artery disease ✓ diabetes/insulin resistance ✓ risk of developing cancer

DIAGNOSIS T/F: however, some patients with acromegaly have normal random levels of GH.

True

DIAGNOSIS ● patients with normal, random levels of GH, elevated levels of ____

IGF-I

Definitive test for acromegaly

nonsuppressibility of GH to glucose loading

TREATMENT ACROMEGALY

Transsphenoidal adenomectomy External beam or focused irradiation

THREE DIFFERENT CLASSES OF GH SUPPRESSION AGENTS

SS analogs dopaminergic agonists GH receptor antagonists

Example of SS analogs

octreotide and lanreotide

Example of dopaminergic agonists

cabergoline and bromocriptine

Example of GH receptor antagonist

pegvisomant

GH deficiency occurs in

both children and adults.

GH DEFECIENCY In ______, it may be familial or due to tumors, such as _____________.

children craniopharyngiomas

GH DEFECIENCY In _______, it is a result of structural or functional abnormalities of the _______.

adults pituitary

GENETIC DEFECT A (recessive/dominant) mutation in the _____ gene that causes a failure of GH secretion

recessive GHRH

In genetic defect, there is a loss of ______

GH gene itself

GENETIC DEFECTS Mutations that cause GH ______

insensitivity

GENETIC DEFECTS structural lesions of the ______ or _______ may also cause GH deficiency and may be associated with other _____________________________.

pituitary hypothalamus anterior pituitary hormone deficiencies

An ___________ has been described in patients who have complete or even partial failure of the anterior pituitary.

adult GH deficiency syndrome

An adult GH deficiency syndrome has been described in patients who have complete or even partial failure of the _________

anterior pituitary.

Symptoms of Adult GH Deficiency Syndrome ✓ __________ ✓ _________ ✓ _________ ✓ _____________________ ✓ Frequent concomitants of adult GH deficiency are __________ and alterations in _________ ✓ ___________ with the advent of recombinant ________

✓ social withdrawal ✓ fatigue ✓ loss of motivation ✓ diminished feeling of wellbeing ✓ Osteoporosis, body composition ✓ GH replacement therapy, human GH

Considered a stress hormone

Prolactin

Prolactin is considered as a _____

stress hormone

● Has vital functions in relation to reproduction

Prolactin

Prolactin has has vital functions in relation to _______

reproduction

Classified as a direct effector hormone

Prolactin

Prolactin is classified as a ___________

direct effector hormone

the physiologic effect of prolactin is ________

lactation

● tonic inhibition is its major mode of hypothalamic regulation

Prolactin

PROLACTIN ● _________is its major mode of hypothalamic regulation

tonic inhibition

inhibits prolactin

Dopamine

Pituitary tumor directly secreting prolactin

Prolactinoma

Most common type of functional pituitary tumor

Prolactinoma

PROLACTINOMA Clinical presentation depends on the ________ of the patient and the ________

age and gender size of the tumor

HYPERPROLACTINEMIA CAUSES

● Medications (dopaminergic antagonist) ● Disruption of the pituitary stalk ● Increased Thyrotropin-releasing Hormone ● Pathologic stimulation of neural sucking reflex ● Primary thyroidal failure ● Renal failure ● Polycystic ovary syndrome ● Pregnancy ● Exercise and seizures

MANAGEMENT OF PROLACTINOMA Therapeutic goals

1. Decreasing tumor mass 2. Restoration of normal gonadal function and fertility 3. Osteoporosis prevention 4. Preservation of normal anterior and posterior pituitary function

MANAGEMENT OF PROLACTINOMA Therapeutic Options

1. Simple observation 2. Surgery 3. Radiotherapy 4. Medical management with dopamine agonists

FACTORS TO CONSIDER FOR PROLACTINOMA MANAGEMENT:

1. Tumor size 2. Preferences of the patien

TUMOR SIZE

Macroadenomas Microadenomas

Macroadenomas size

>10 mm

Microadenomas size

<10 mm

Among the tumor sizes, which is LESS likely to be cured?

Macroadenomas

most commonly used therapy for microprolactinomas

Dopamine agonists

● cause tumor shrinkage in >90% of patients

DOPAMINE RECEPTOR AGONISTS:

DOPAMINE RECEPTOR AGONISTS: ● cause tumor shrinkage in ____ of patients

>90%

DOPAMINE RECEPTOR AGONISTS: also shrink ________________

prolactin-secreting macroadenomas

T/F: Dopamine receptor agonist is discontinued during pregnancy unless tumor regrowth is detected

True

Types of Dopamine receptor agonists

1. Bromocriptine mesylate 2. Cabergoline

Example of Bromocriptine mesylate

Parlodel

Example of Cabergoline

Dostinex

DOPAMINE RECEPTOR AGONISTS Has an adverse effects

Bromocriptine mesylate

What are the adverse effect of Bromocriptine mesylate

orthostatic hypotension, dizziness, nausea, GI problems

BROMOCRIPTINE MESYLATE Remedy for GI adverse effects: __________

intravaginal administration

DOPAMINE RECEPTOR AGONISTS Fewer adverse effects

Cabergoline (Dostinex)

DOPAMINE RECEPTOR AGONISTS Administered weekly due to its longer duration of action

Cabergoline (Dostinex)

Cabergoline (Dostinex) is linked to

valvular heart disease development

Cabergoline (Dostinex) is linked to valvular heart disease development - due to its ability to interact with _________________________________________________

5-hydroxytryptamine (5-HT)2B serotonergic receptor

NOT a primary mode of prolactinoma management

NEUROSURGERY

● Indications for neurosurgical intervention:

1. Pituitary tumor apoplexy (hemorrhage) 2. Acute visual loss due to macroadenoma 3. Cystic prolactinoma 4. Intolerance to medical therapy 5. Tumor resistance to dopaminergic agonists

Surgical cure rates are (directly/inversely) proportional to ______ and degree of ________

INVERSELY tumor size prolactin elevation.

Reserved for high surgical risk patients with locally aggressive macroadenomas and intolerance to dopamine agonists

RADIOTHERAPY

Radiotherapy is reserved for high surgical risk patients with locally aggressive _________ and intolerance to __________

macroadenomas dopamine agonists

condition with unknown cause

Idiopathic

- inappropriate lactation

Galactorrhea

Lactation occurring in women with normal prolactin levels

IDIOPATHIC GALACTORRHEA

Seen in women who have been pregnant several times and has no pathologic implication,

IDIOPATHIC GALACTORRHEA

T/F: Idiopathic galactorrhea may be a manifestation of a localized increased sensitivity to prolactin in breast tissue.

True

A diagnosis of exclusion

IDIOPATHIC GALACTORRHEA

Failure of either the pituitary gland or the hypothalamus

Hypopituitarism

● Loss of anterior pituitary function

Hypopituitarism

HYPOPITUITARISM Loss of ___________

anterior pituitary function

HYPOPITUITARISM Complete loss of function: ______

panhypopituitarism

HYPOPITUITARISM Single loss of a pituitary hormone:

monotropic hormone deficiency

HYPOPITUITARISM Immediate detectable lost hormones:

tropic hormones

Example of tropic hormones lost in Hypopituitarism

ACTH TSH LH, FSH

HYPOPITUITARISM Delayed unnoticeable lost hormones:

direct effectors (GH and prolactin)

HYPOPITUITARISM LABORATORY DIAGNOSIS (Primary/Secondary) failure is accompanied by dramatic (decrease/increase) in circulating levels of the corresponding _________

Primary increases pituitary tropic hormone

HYPOPITUITARISM LABORATORY DIAGNOSIS ___________ is associated with low or normal levels of ________

Secondary failure tropic hormones

HYPOPITUITARISM LABORATORY DIAGNOSIS T/F: Only tropic hormone is measured.

FALSE; Both tropic and target hormone levels should be measured

Most common cause of hypopituitarism

Pituitary tumors

Infections in Hypopituitarism

fungal infections tuberculosis syphilis

infiltrative disease in Hypopituitarism

hemochromatosis sarcoidosis, or histiocytosis

Immunologic (hypopituitarism)

lymphocytic hypophysitis

Familial (hypopituitarism)

Kallmann’s syndrome; rare

TREATMENT OF PANHYPOPITUITARISM:

● Replacement therapy ● Thyroxine, glucocorticoids, and gender-specific sex steroids ● Pulsatile GnRH infusions: ● Gonadotropin preparations:

TREATMENT OF PANHYPOPITUITARISM: for patients with Kallmann's syndrome

Pulsatile GnRH infusions

TREATMENT OF PANHYPOPITUITARISM: for patients with gonadotropin deficiency

Gonadotropin preparations

POSTERIOR PITUITARY HORMONES a.k.a

NEUROHYPOPHYSIS

Extension of the forebrain

POSTERIOR PITUITARY HORMONES / NEUROHYPOPHYSIS

POSTERIOR PITUITARY HORMONES / NEUROHYPOPHYSIS is extension of the _____

forebrain

Serves as storage for two homologous nonapeptides

POSTERIOR PITUITARY HORMONES / NEUROHYPOPHYSIS

What are the two homologous nonapeptides stored in Posterior pituitary hormones/Neurohhypophysis

ADH & Oxytocin

Both have an autocrine or a paracrine function

ADH & OXYTOCIN

ADH & OXYTOCIN Both have an ________ or a _______ function

autocrine paracrine

Originate primarily in the paraventricular nuclei of the hypothalamus

Oxytocin

OXYTOCIN Originate primarily in the ____________ of the hypothalamus

paraventricular nuclei

Oxytocin plays a major role in

lactation labor parturition

OXYTOCIN Unique because its secretion responds in a ________________

positive feedback mechanism

ACTION OF OXYTOCIN 1) contraction of ___________ 2) contraction of the ___________

myoepithelial cells in the breast uterus

The contraction of myoepithelial cells in the breast causes _________

ejection of milk

The contraction of uterus induces ________

labor

A synthetic oxytocin

Pitocin

● Used in obstetrics to induce labor

Pitocin

Pitocin is used in obstetrics to ______

Induce labor

Recent Studies linked Oxytocin to a variety of biosocial behaviors including _________ and ___________

maternal nurturing mother-infant bonding.

Oxytocin, also has been shown to have effects on ________________ (5)

pituitary renal cardiac metabolic immune function

Synthesized by hypothalamic supraoptic nuclei

ADH

ADH is synthesized by

hypothalamic supraoptic nuclei

ADH Stimulus: (inc/dec) plasma osmolality, (inc/dec) BP and BV

inc dec

ADH Its significant role is to regulate ___________, hence has a central role in ________

renal free water excretion water balance

ACTIONS OF ADH RECEPTORS

V2 receptors V1 receptors

increases H20 permeability (aquaporin-2) of cells in renal collecting tubules and ascending loop of Henle via V2 receptors coupled with adenylate kinase

● V2 receptors

V2 RECPETORS increases H20 permeability (______) of cells in _________ and ascending _______ via V2 receptors coupled with __________

aquaporin-2 renal collecting tubules loop of Henle adenylate kinase

capable of vasoconstriction via V1 receptors coupled with Phospholipase C

V1 Receptors

V1 RECEPTORS capable of _________ via V1 receptors coupled with ______________

vasoconstriction Phospholipase C

● Regulates release of vasopressin from posterior pituitary

HYPOTHALAMIC OSMORECEPTORS AND VASCULAR BARORECEPTORS

HYPOTHALAMIC OSMORECEPTORS AND VASCULAR BARORECEPTORS ● Regulates release of vasopressin from ________

posterior pituitary

extremely sensitive even to small changes in plasma osmolality

Osmoreceptors

OSMORECEPTORS ______________ADH average osmotic threshold

284 mOsm/kg

T/F: When plasma osmolality increases ADH secretion also increases

True

When plasma osmolality increases ADH secretion also increases, which in turn (reduces/increases) renal free water clearance, (increasing/lowering) plasma osmolality and returning ________

reduces lowering homeostasis

Vascular Baroreceptors locations

left atrium aortic arch carotid arteries

initiate ADH release in response to decreased BV or BP – 5% to 10% fall in arterial BP in normal humans

→ Vascular Baroreceptors

VASCULAR BORORECEPTORS initiate ADH release in response to (increased/decreased) BV or BP – ______ fall in arterial BP in normal humans

decreased 5% to 10%

T/F: Baroreceptor-induced ADH secretion will override the normal osmotic suppression of ADH secretion

true

PATHOPHYSIOLOGY OF ADH DEFICIENCY

● Diabetes Insipidus ● Primary polydipsia

characterized by polyuria, and polydipsia

● Diabetes Insipidus

A typical patient presents with a partial ADH deficiency

● Diabetes Insipidus

→ Causes of hypothalamic DI:

o Apparent autoimmunity to ADH-secreting neurons o Trauma o Diseases affecting pituitary stalk function o Various CNS or pituitary tumors

____ of patients will have idiopathic DI

30%

Diagnosis of DI Secured diagnosis of DI if inappropriately (low/high) ADH level with (decreased/increased) plasma osmolality

low increased

TESTS FOR DIABETES INSIPIDUS

✓ Water deprivation Test ✓ Therapeutic Trial of ADH or Synthetic Analog

✓ Therapeutic Trial of ADH or Synthetic Analog such as ___________

desmopressin (dDAVP)

compulsive water consumption, water intoxication

Primary polydipsia

TREATMENT FOR ADH EXCESS

1. Restricting water intake to small amounts each day for ADH excess 2. Conivaptan and tolvaptan, ADH V2 receptor antagonists

TREATMENT FOR ADH EXCESS a historical cornerstone of treatment

1. Restricting water intake to small amounts each day for ADH excess

TREATMENT OF ADH EXCESS approved for management of euvolemic hyponatremia due to ADH excess

Conivaptan and tolvaptan, ADH V2 receptor antagonists