Pituitary Gland Hormone Drugs Flashcards by Maria P.

Hormone released from posterior pituitary

ADH = Vasopressin
Oxytocin

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Hormones released from anterior pituitary

ACTH
Growth hormone (GH)
Prolactin (PRL)

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GROWTH HORMONE ; secretion regulated by

Most abundant anterior pituitary hormone

Secretion regulated by:
 Hypothalamic GH releasing factor (GHRF)
 Somatostatin
 Insulin-like growth factor (IGF)-1

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GH Anabolic effects

 Bone growth
 Bone mineral density increase after the epiphyses have closed
 Increased muscle mass
 Protein synthesis

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Metabolic Effects of GH

 Increased lipolysis
 Gluconeogenesis stimulation

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SOMATROPIN CLINICAL USES

Pituitary dwarfism
- Lack of GH
- Lack of GHRF
- Lack of IGF generation or action
Turner’s syndrome
AIDS-associated wasting
Used illicitly by athletes

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SOMATROPIN RoA

Recombinant GH: SC

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ADVERSE EFFECTS
Of Somatotropin (in kids + adults)

-Few side effects in children

-Adults:
 Peripheral edema
 Carpal tunnel syndrome
 Arthalgias
 Myalgia
 Insulin resistance

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RECOMBINANT IGF-1 example:

Mecasermin

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Mecasermin Clinical uses

ONLY FOR KIDS

Treatment of growth failure in children:
 Lack adequate amounts
of IGF  GH deficiency alternative
to recombinant GH
 GH is more effective

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Mecasermin RoA

SC injection

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Excessive production of GH

Children -> Gigantism
Adults -> Acromegaly

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Medication for Acromegaly

‘Pegvisomant
, Dopamine agonist, bromocriptine, also used

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What is Pegvisomant

Recombinant modified version of GH

 Highly selective antagonist of GH actions
 Alternative to SST analogues if they have failed

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Dopamine agonist PK/PD

Less effective
Decreases production of GH from pituitary gland

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SOMATOSTATIN in anterior pituitary

 Inhibits release of Growth Hormone (GH)
 Inhibits release of Thyroid Stimulating Hormone (TSH)

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SOMATOSTATIN in Pancreas

Inhibits insulin and glucagon release

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SOMATOSTATIN in GI tract

Reduces gastric acid and pancreatic secretions

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-SOMATOSTATIN ANALOGUES exs.

Octreotide, lanreotide

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‘Octreotide, lanreotide Clinical uses

 Acromegaly : Favoured treatment
 Carcinoid and other hormone-secreting tumours  Bleeding oesophageal varices: Constricts splanchnic blood vessels

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Octreotide, lanreotide AE

‘Injection site pain (SC injection), GI disturbances,
gallstones, postprandial hyperglycemia, hypothyroidism

PROLACTIN MoA

 Mediates mammary development: lactation
 Secreted from the anterior pituitary by lactotroph
(mammotroph) cells

Prolactin secretion is under tonic inhibitory
control by hypothalamus
Regulated by:

• Dopamine (D2 receptors):

- Dopamine agonists (bromocriptine, cabergoline)
       - Suppress prolactin release 

- Dopamine antagonists
        Stimulate prolactin release

Clinical uses of bromocriptine

to prevent lactation
to treat galactorrhea, owing to excessive prolactin secretion
to tx prolactin-secreting pituitary tumours (prolactinomas)
in the treatment of parkinsonism and of acromegaly

DOPAMINE PATHWAYS

1. Nigrostriatial (75%) – corpus striatum – regulates motor function 2. Mesolimbic – nucleus accumbens and amygdala – regulates emotion 3. Mesocortical – limbic cortex – regulates attention/cognition 4. Tuberohypophysial – pituitary gland – regulates prolactin release

AE of Dopamine agonists/ bromocriptine

-Nausea/vomiting - Headache - Postural hypotension -Less frequent:  Psychosis/hallucinations  Insomnia

DOPAMINE ANTAGONISTS exs

-Metoclopramide; domperidone Primarily are prokinetics + anti-emetics

DOPAMINE ANTAGONISTS clinical uses

- to increase milk supply  Off-label use during breast-feeding  Anti-psychotics may cause galactorrhea as a side effect

VASOPRESSIN RECEPTORS

V1A, V1B (V3), V2

V1A. Physiological actions

- Phospholipase C/IP3 system activation - Contraction of smooth muscle

V1B (V3) physiological axns

' Phospholipase C/IP  Release of adrenocorticotropic hormone (ACTH) from anterior pituitary

V2 physiological actions !

 Stimulation of adenylyl cyclase  Action in collecting ducts of the nephron - Increases permeability to water (aquaporin insertion)  Release of blood coagulation factors

Desmopressin : Properties

Increased duration of axn (cf ADH) V2 selective

Desmopressin Clinical uses

 Central diabetes insipidus  Persistent nocturnal enuresis  Prophylaxis against bleeding in haemophilia

Terlipressin Properties

Increased duration of action (cf ADH) Minimal anti diuretic properties More V1 selectivity

Terlipressin Clinical use

, Initial treatment of bleeding oesophageal varices

'ADVERSE EFFECTS of Vasopressin

- Few unwanted side effects - V 1 -mediated: •Facial pallor • Increased intestinal activity (nausea/cramps) • Spasm of coronary arteries (angina) • Reduced cardiac output - V2-mediated •Water intoxication [ increased intracranial pressure] [ seizures]

Tolvaptan Clinical uses

' Treatment of syndrome of inappropriate ADH secretion (‘SIADH’)  Hypervolemic or euvolemic hyponatremia

Tolvaptan properties + RoA

Selective V2 antagonist Oral

Conivaptan clinical use

 Hypervolemic or IV euvolemic hyponatremia in hospitalized patients

Conivaptan properties + RoA

Non-selective V1A /V2 antagonist IV

Tolvaptan AE

GI-related adverse effects, hyperglycemia, pyrexia

Conivaptan AE

 Drug-drug interactions preclude chronic use  Infusion-site reactions ( like any injectables)

DEMECLOCYCLINE Clinical indication + what to treat it

 Tetracycline  Rarely used as an antimicrobial agent  Used to treat SIADH V2 antagonist

DEMECLOCYCLINE AE

 Nephrogenic DI  Photosensitivity  Abnormalities of bone and teeth

DRUGS INHIBITING BIOSYNTHESIS

- Metyparone - Trilostane - aminoglutethimide - ketoconazole

'Metyparone properties

Test for ACTH production Cushing’s syndrome

Trilostane (no longer used) Properties

Cushing’s syndrome Primary hyperaldosteronism

Aminoglutethimide (no longer used) properties

Cushing’s syndrome Advanced breast/prostate cancer

Ketoconazole properties

Cushing’s syndrome