Which one of the following pairs of lipids and related compounds exhibit opposite biologic activities?
|A||5-HPETE and leukotriene D4|
|B||Cholic acid and lithocholic acid|
|C||Thromboxane A2 and prostacyclin PGI2|
|D||Acetone and beta - hydroxybutyrate|
a. Eicosanoids are formed from C2O polyunsaturated fatty acids.
b. Arachidonate and some other C2O fatty acids with methylene interrupted bonds give rise to EICOSANOIDS, physiologically and pharmacologically active compounds known as Prostaglandin PG, Thromboxanes TX, Leukotrienes LT and Lipoxins
c. Thromboxanes are synthesized in platelets and upon release cause vasoconstriction and platelets aggregation.
d. ProstacyclinsPGI are produced by blood vessels walls and are potent inhibitors of platelets aggregation. Thus, thromboxanes and prostacyclins are antagonistic.
a. Ketone — bodies
i. synthesized in Liver mitochondria
ii. they are — Aceto-acetate, 3-hydroxybutyrate Beta — hydroxybutyrate and acetone
iii. they are important sources of energy for the peripheral tissues.
b. Bile acid:
a. About - gm of cholesterol is excreted via conversion to bile a cid.
b. Primary bile acids are synthesized in the liver from cholesterol — eg. Cholic a cid and chenodeoxycholic acid.
c. Secondary bile acids are derived from primary bile acids by action of intestinal bacteria De conjugation and 7 α- De hydroxylation
Eg.Deoxycholic acid from cholic acid and Lithocholic acid from Chenodeoxycholic acid