Basic Endocrine Principles Flashcards
Components of Endocrine System (9)
Pineal Gland Hypothalamus Thyroid gland Pituitary Gland Thymus Pancreas Adrenal Glands Testes Ovaries
Hormone Subtypes (3)
Amino acid derived
Proteins and Peptides
Steroid Hormones
Protein and peptide examples (3)
Oxytocin
Growth hormone
Follicle Stimulating Hormone (FSH)
Amino acid derived
Adrenaline
Melatonin
Steroid Hormones
Testosterone
Oestradiol
Hormone Receptors (5)
G-protein coupled receptors Tyrosine Kinase Receptors Cytokine Receptors Steroid Hormone Receptors Glucocorticoid Receptors
G-protein coupled receptors
7 transmembrane domain and an associated G-protein complex
Activation of a limited number of regulatory signalling cascades
(e.g. cAMP, IP3, P13 K)
Loss of function mutations in GPCRs can lead to some endocrine diseases.
Tyrosine Kinase Receptors
Intrinsic tyrosine kinase activity
Insulin Receptor
Cytokine Receptors
Linked to tyrosine kinase activity
Prolactin Receptor
Growth hormone receptor
Steroid hormone receptors
Typically intracellular - nucleus or cytoplasm
Nuclear receptor family include oestrogen and androgen receptors
Steroid receptor complex binds DNA response elements.
Result in change in gene transcription
Hypothalamic Pituitary Axis
Negative feedback loop
Hormones released by posterior pituitary (2)
Antidiuretic hormone
Oxytocin
Hormones released by anterior pituitary (6)
Growth Hormone Luteinising Hormone Follicle Stimulating Hormone Adrenocorticotropic Hormone (ACTH) Thyroid Stimulating Hormone Prolactin Hormone
Hypothalamic Pituitary Adrenal (HPA) Axis
Negative Feedback Loop
–> Cortisol
Hypothalamus secretes corticotropin releasing hormone.
Causes anterior pituitary to secrete ACTH
Results in adrenal cortex secreting cortisol
Cortisol can result in multiple physiological effects.
Can also negatively feedback on hypothalamus or anterior pituitary.
Hypothalamic Pituitary Gonadal Axis
Hypothalamus causes secretion of GnRH (gonadotropin releasing hormone)
Acts on anterior pituitary gland to secrete luteinising hormone and follicle stimulating hormone
Produce response in gonads (ovaries or testes)
The testosterone produced by testes or oestrogen produced by ovaries can then act as a feedback loop on pituitary or hypothalamus.
