Hormone Signalling Pathway Flashcards
How much oestrogen is in the contraceptive pill?
35 micrograms
What makes up 30% of cell membranes?
Lipids with an -OH group (alcohol)
How much cell membrane is synthesised a day?
1g a day.
Characteristics of steroid hormones:
Have both hydrophilic and hydrophobic properties.
Can penetrate through membranes
What are the two types of steroid hormones?
Corticosteroids
Sex steroids
Corticosteroids:
Mineralocorticoids
Glucocorticoids
(Made in adrenal cortex)
Sex steroids:
Androgens
Progesterone
Oestrogen
(Made in gonads / placenta)
What is a DNA binding domain made of?
4 cystine residues and a zinc atom.
Forms a loop which can access the major groove of DNA.
What phases make up the transcriptional response to nuclear receptor stimulation?
Primary response phase
Secondary response phase
What happens in the primary response phase of transcriptional response?
Receptor-hormone complex switches on primary response genes.
Primary response proteins are synthesised.
What happens in the secondary response phase of transcriptional response?
The primary response proteins switch OFF primary response gene expression.
Primary response proteins switch ON secondary response gene expression.
Secondary response proteins are synthesised.
What is a glucocorticoid receptor?
Mediates actions of glucocorticoids.
What is a glucocorticoid?
Immunosuppressant and anti-inflammatory agent.
What are the side effects of glucocorticoids?
Bone loss, glucose dysregulation.
What is the hypothalamic pituitary axis?
Releases ACTH and CRH
Stress response and regulates sugar levels
What is Addison’s disease?
TOO LITTLE CORTISOL
Causes damage to adrenal glands
Lack of ACTH.
Depression, flu like symptoms, weight loss.
What is an Adison’s crisis?
Caused by sudden stress, E.g. an operation, accident, infection.
What is Cushings syndrome?
TOO MUCH CORITSOL
Can be caused by an adenoma growing on adrenal glands, causing increased ACTH production.
Weight gain, high blood pressure, puffy face.
Caused by steroid use / abuse.
What are the 3 steps of insulin signalling?
- Tyrosine kinase phosphorylates receptor and its substrates
- Activation of lipid kinase (P13K)
- Activation of AKT
What does AKT phosphorylate?
Tyrosine / Serine residues
(FOXO transcription factors, TSC2, MTORC1, S6K, SREBP1c, GSK3, TBC1D4)
What is type I diabetes?
Destruction of beta cells, often caused by an auto-immune attack.
What is type II diabetes mellitus?
Dysregulation of metabolism, impaired insulin direction / insulin resistance.
What is the treatment for type II diabetes?
Metformin. It decreases insulin resistance and promotes weight loss. It activates AMPK which regulates glucose metabolism.
It is positively charged so it accumulates in cell and mitochondria membranes.
