8.5.1.2 Prostaglandins: Pharmacological Effects
The pharmacological effects of the prostaglandins and TXA 2 comprise many different
activities—in fact too many. The lack of specificity of their activities implies a number of
side effects which preclude the clinical application of several highly active natural
prostaglandins, necessitating the development of selective synthetic compounds. The fol-
lowing effects of prostaglandins/eicosanoids are known and are summarized in table 8.3.
522 MEDICINAL CHEMISTRY
Table 8.3Biologic Activities Associated with the Eicosanoids
Substance Observed biologic Activity
PGD 2 Weak inhibitor of platelet aggregation
PGE 1 Bronchodilatation
Inhibitor of fat breakdown
Inhibitor of platelet aggregation
Stimulates contraction of gastrointestinal smooth muscle
Vasodilation
PGE 2 Elevates body temperature set-point in anterior hypothalamus
Protects stomach lining acid degradation
Reduces secretion of stomach acid
Renal vasodilatation in kidneys
Stimulates uterine smooth-muscle contraction
PGF 2 Stimulates uterine smooth-muscle contraction
PGl 2 Potent inhibitor of platelet aggregation
Potent vasodilator
PGJ 2 Inhibits cell proliferation
Stimulates osteogenesis (bone formation)
TXA 2 Potent inducer of platelet aggregation
Potent vasoconstrictor
Stimulates release of serotonin from platelets
LT B 4 Increases leukocyte chemotaxis and aggregation
LTC/D 4 Bronchoconstrictive
5- or 12-HPETE Inhibits platelet aggregation
Aggregates leukocytes
Promotes leukocyte chemotaxis