30 12 Nov 2010

30 12 Nov 2010 - Lipids as Signals, Cofactors, and Pigments...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Lipids as Signals, Cofactors, and Pigments Storage Lipids - triacylglycerides Structural Lipids – glycerol, sphingosine, sterol based Signal Lipids – hormones, cofactors (vitamins), and conjugated pigments External signals activate phospholipase C Phosphatidylinositol 4,5-bisphosphate is cleaved to release two products, IP3 and DAG, that act as intracellular messengers Inositol 1,4,5-trisphosphate (IP3), a cytosolic signal, triggers release of Ca 2+ . from the endoplasmic reticulum Diacylglycerol, remains in the plasma membrane and activates the enzyme protein kinase C when cytosolic Ca 2+ levels are elevated.
Background image of page 2
Endocrine signaling through circulation Paracrine signaling through local diffusion Eicosanoids (eico = 20) are paracrine hormones derived from arachidonic acid 20:4( 5,8,11,14 ) Prostaglandins – first isolated from prostate tissue Thromboxanes – first isolated from thrombocytes (platelets) Leukotrienes – first isolated from leukocytes
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Prostaglandins = 5 – carbon ring Two groups of prostaglandins were originally defined: PGE ( e ther-soluble) and PGF ( f osfat (Swedish for phosphate) buffer–soluble). Each group contains numerous subtypes, named PGE1, PGE2, PGF1, and so forth. Participate in a wide range of body functions such as the contraction and relaxation of smooth muscle, the dilation and constriction of blood vessels, control of blood pressure, and modulation of inflammation.
Background image of page 4
Thromboxanes = 6 – carbon ring Either of two compounds, one designated A2 and the other B2. Thromboxane A2 is synthesized by platelets and is an inducer of platelet aggregation and platelet release functions and is a vasoconstrictor; it is very unstable and is hydrolyzed to thromboxane B2 The nonsteroidal antiinflammatory drugs (NSAIDs)—aspirin, ibuprofen, and meclofenamate,for example—inhibit the enzyme prostaglandin H2 synthase (also called cyclooxygenase, or COX)
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
COX-2 Inhibitors, Other NSAIDs, and Cardiovascular Risk. The Seduction of Common Sense David J. Graham, MD, MPH. JAMA. 2006;296
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 19

30 12 Nov 2010 - Lipids as Signals, Cofactors, and Pigments...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online