Control of Appetite Flashcards
Where is the appetite centre located?
Arcuate nucleus of the hypothalamus. Primary neurones - sense metabolite levels/respond to hormones. Secondary neurones - synthesis input and co ordinate a response via vagus nerve
Describe the divisions of primary neurones
Excitatory - stimulate appetite via release of NPY and AgRP
Inhibitory - suppresses appetite by releasing POMC
What can POMC be cleaved to produce?
Beta-endorphin, ACTH and alpha-MSH
What is the function of ghrelin?
It’s a peptide hormone which is released when the stomach is empty. Stimulates excitatory neurones.
What is the function of leptin?
A peptide hormone released from adipocytes which stimulates inhibitory neurones and inhibits excitatory neurones. Induces expression of UCP
What is PYY?
Peptide hormone released from the wall of the small intestine. Suppresses appetite
What is amylin?
Peptide hormone secreted from beta cells, known to suppress appetite and inhibit glucagon secretion
What is the effect of insulin?
Insulin suppresses appetite by stimulating inhibitory neurones and inhibiting excitatory neurones. Induces expression of UCP. Leptin is more important in these roles
What is pramlintide?
Analogue of amylin - could be a potential hypoglycaemic agent in early type 2 diabetes
What is metabolic syndrome?
Group of symptoms including insulin resistance, dyslipidaemia, glucose intolerance and hypertension associated with central adiposity.
What criteria have WHO set out for metabolic syndrome?
Central obesity with a waist:hip ratio >0.9 (men) >0.85 (women), BMI above 30kg/m², blood pressure >140/90mmHg, TAGs >1.7mmol/L, HDL cholesterol 7/8mmol/L
What is the Barker hypothesis?
Experience of the foetus in utero during development somehow determines the future health of the individual.
What is epigenetics?
A stably inherited phenotype resulting from changes in a chromosome without alterations in the DNA sequence. Involves methylation of DNA which alters histone structure causing suppression of gene transcription
