Week 6 Signals Flashcards
Signals, cofactors & pigments
Family of lipids that have active roles – metabolites and messengers
— Hormones
— Enzyme cofactors
— Pigment molecules – absorb visible light
Phosphatidylinositol’s – in signalling
Phosphatidylinositol 4,5-bisphosphate (PIP2)
—Located in cytoplasmic face of plasma membranes
— Reservoir of messenger molecules
—Formation of inositol 1,4,5-triphosphate (IP3)
— Important in muscle contraction
Phosphatidylinositol 3,4,5-triphosphate
Pip2 can be broken down into ip3
Phosoporalated into pip 3 = useful for glucose transporters
Eicosanoids
Eicosanoids – paracrine hormones
— All derived from arachidonic acid
— Roles in reproduction, inflammation, fever, pain, formation of blot clots, blood pressure regulation, gastric acid secretion ……
— Three classes
— Prostaglandins (PG) - causes inflammatory response,swelling, regulation of temperature, production of acid in the stomach
— Thromboxanes
— Leukotrienes
Enzymatic oxidation of arachidonic acid yields
—Prostaglandins
— Elevate temperature (fever)
— Affects blood flow
— Contraction of smooth muscle in menstruation & labour
— Thromboxanes
— Produced by platelets
— Role in formation of blood clots
— Reduce local blood flow
— Leukotrienes
— Contraction of smooth muscle in lung
— Contraindicated in asthmatics & anaphylactic shock
Steroid hormones
Oxidised derivatives of sterols
Move through the bloodstream bound to plasma proteins
4 carbon ring
Oxidised derríbate d of cholesterol
Can pass through plasma membrane
Lipifilic profile
Corto sol
Vitamins
Water soluble - vitamin B group, vitamin C
Fat soluble- Vitamin A, D,E,K
Can be considered as a hormone
Vitamin d can be stored up to 3 months in liver then metabolised to circulate into more active form
Vitamin D
Vitamin A
Lipid vitamin
Oxidation of carbon 15 retinol > retinal
Retinoic acid > signal to epthilal cell