Endocrine pharmacology Flashcards
LO
- Describe the role of corticotrophin and adrenal steroids.
- Describe the role of the hypothalamic pituitary axis
- Describe the female reproductive system and contraceptive drugs.
- Describe the endocrine pancreas and the control of blood glucose
Lecture content
- Overview of the endocrine system; the role of the hypothalamic pituitary axis
- Corticotrophin and adrenal steroids
- The female reproductive system and contraceptive drugs
- The endocrine pancreas and the control of blood glucose
Which label represents the pituitary gland?
b
a is the hypothalamus
What hormone is produced when stressed?
If stressed, you have an increased level of cortisol as the limbic system connected to hypothalamus which is connected to anterior and posterior pituitary which is involved in hormone production
Which of the following statements is false…
- The anterior and posterior pituitary have the same embryological origin
- The pituitary stalk contains a portal blood supply
- The release of hormones from the anterior pituitary is controlled by releasing factors
- There is a region in the pituitary called the intermediate lobe
1 is false
The pituitary is an organ of dual origin. The anterior lobe (adenohypophysis) is derived from oral ectoderm and is epithelial in origin, whereas the posterior lobe (neurohypophysis) derives from the neural ectoderm.
Tell me the relationship between the hypothalamus and the anterior and posterior pituitary glands
How does the hypothalamus signal to the anterior pituitary?
Explain the feedback loops and draw the diagram
- RF travel in portal blood supply and act on anterior pituitary
- The loop has a negative feedback loop; once hormones released from anterior pituitary they can feedback and act on receptors on the anterior or in the hypothalamus to inhibit the further release of the RF or the hormone (controls the amount of hormone circulating the body at any one time)- provides for homeostasis
- Control from posterior pituitary doesn’t contain RF
What are releasing factors?
releasing factors (RF) are hypothalamic hormones
Most are Neuropeptides (sequences of AA)- the clue to their role is in their name
Give some examples of neuropeptides
- Growth hormone-releasing factor (GHRF)
- Somatostatin (GH inhibiting factor)
- Thyrotrophin-releasing hormone (TRH)- 3 AA long
- Corticotrophin-releasing factor (CRF)
give an example of a hypothalamic hormone that isnt a neuropeptide
Tell me its sequence from release to target
DOPAMINE – this is a catecholamine not a neuropeptide
a precursor for noradrenaline in the brain
it inhibits prolactin release
released from the hypothalamic neurones –> portal blood supply where its –>released form the anterior pituitary –> inhibits prolactin release
Tell me the cells of the anterior pituitary and their function
- Lactotrophs- release prolactin
- Somatotrophs- release GH
- Corticotrophs- release corticotrophin and control cortisol levels
- Gonadotrophs- control hormones to do with gonads and reproduction
- Thyrotrophs- release TSH
How does the hypothalamus signal to the posterior pituitary?
Tell me the posterior pituitary hormones, where the cells they are secreted from are located and the major functions of the hormone?
Summary of pituitary hormones
Tell me some disorders fo the hypothalamic-pituitary axis
Growth hormone
Thyroid hormone
Diabetes insipidus
What type of hormone is GH and what does this mean?
GH = Anabolic hormone (builds up body tissue and builds muscle by stimulating AA uptake into muscle)
Tell me some of the major functions of GH?
- Stimulates amino acid/protein uptake into muscle.
- Stimulates IGF-1 (insulin-like growth factor-1) release from liver. IGF-1 is a somatomedin- anabolic
- IGF-1 especially important in growth of skeleton and cartilage
- (GH inhibits glucose uptake)- increases circulating levels of glucose in body. Works in an antagonistic fashion to insulin (Diabetes can be a side effect to levels of GH)
Tell me some disorders that can occurs from GH secretion?
In childhood: Altered growth/stature (could be too much or too little) e.g., gigantism due to excessive GH in adulthood and dwarfism if too little GH
In adulthood: ↑GH Acromegaly (enlargement in soft tissues)
Tell me some different treatmenrs for the GH insufficiency pituitary dwarfism
- Injection human recombinant GH (Somatropin)
- Injection of human recombinant IGF-1 (Mecasermin) –
abnormal GH receptor Laron’s dwarfism: typically caused by mutations in the GH receptor which is located on the liver so can no longer produce IGF-1
GHRF–> acts via anterior pituitary –> GH –> Liver –> IGF1
- Sermorelin is a GHRF analogue- used a diagnostic and also to increase growth in children.
Can treat with GHRF as would predict to see an increase in GH and if there isn’t then there’s an issue in the anterior pituitary. But if do see an increase then could be due to issue with GHR. Can be used as a diagnostic to look at how levels differ (think about signaling cascade to thing about how treatments and diagnostic regiments work)
What is acromegaly?
Excess of GH
Growth of soft tissues especially around the jaw and ears
mild hyperglycaemia (Hyperglycaemia is the medical term for a high blood sugar (glucose) level)
Tell me about the treatment for acromegaly?
The goal of treatment is to restore the pituitary gland to normal function, producing normal levels of growth hormone. Treatment may include removal of the tumor, radiation therapy, and injection of growth hormone blocking drugs. Left untreated, acromegaly can lead to worsening diabetes mellitus and hypertension.
What does thyroid hormone have a key role in?
metabolism and development
What does thyroid hormone increase?
- lipid, carbohydrate and protein metabolism
- oxygen consumption
- heat production
- basal metabolic rate
uncoupling oxidative phosphorylation to bring about calorigenic effect
What does the thyroid gland produce and tell me about this?
Thyroid glands produce: Thyroxine (T4= prohormone) & Triiodothyronine (T3). Both are tyrosine-based hormones which means they contain tyrosine
What does the production of thyroid hormone require?
iodine
What does the thyroid hormone target?
Target cells contain thyroid hormone nuclear receptor (TR)
Tell me a condition that comes about due to a lack of iodine in the diet
Tell me the treatment for it
- Non-toxic goitre (= Derbyshire neck)
- Childhood iodine deficiency= cretinism
- Hyperplasia from lack of thyroid hormones: negative feedback from TH to TRH and TSH stopped. This increases the TSH levels and decreases that to thyroid gland
TRH –> TSH –> acts on thyroid gland –> TH
TH inhibits TSH and TRH via negative feedback loop
- Simple treatment
Give two examples of hypothyroidism?
What types of diseases are these?
- Myxoedema
- Hashimoto’s disease/ Hashimoto’s thyroiditis most common
=autoimmune disease
What are some symptoms of hypothyroidism?
Symptoms: fatigue/depression/weight gain/cold intolerance
Name a hyperthyroid disease?
Graves’ disease (diffuse toxic goitre)- often autoimmune
Give some examples of hyperthyroidism
Symptoms: anxiety/ hyperactivity/ Weight loss/goitre/bulging eyes/ tachycardia/sweating
Cascade for thyroid T3 and T4
What is the structure of Thioureylenes?
-S=C-N-
Give some examples of Thioureylenes
Eg carbimazole, methimazole. Inhibit iodination of tyrosine
What is Protirelin and what is it used for?
Protirelin- synthetic TRH, used diagnostically to test functionality of anterior pituitary to produce thyrotrophin/TSH
How does Thioureylenes inhibit thyroperoxidase?
Tell me disorders of the hypothalamic posterior pituitary axis and treatment?
Tell me the hormones involved
- Antidiuretic hormone/Vasopressin
- (involved in blood volume and osmolarity control)
- ↓ADH Diabetes insipidus; treatments with hormone analogues
Learning outcomes checklist
- Describe the role of the hypothalamic pituitary axis
We have covered:
- how hormones are released from the pituitary gland- giving specific examples.
- conditions associated with pituitary hormone imbalance and what interventions are possible.
Practice essay question
Outline the role of the hypothalamus in regulating tropic hormone release from the anterior pituitary. (70%) Using a named specific example of an endocrine disorder, show the importance of a pharmacological intervention in the above system. (30%)
Adrenal gland hormones