Prostaglandins - types

Prostaglandins:
Prostaglandins are derivatives of prostanoic acid.
With the property of acting as local hormones.
They are most effective pharmacological agents for inducing abortions and labor when the cervix is unripe.
Prostaglandins act through G-protein coupled receptors. PGD2- DP, PGI2 - IP, PEP2, PEP4 act by increasing intracellular C AMP.
PGF2 alfa - FP, PGE2- EP1, EP3 act by increasing intracellular calcium.

PGF2 alfa:
PGF2 alfa is responsible for initiation of menstruation.
It causes vasoconstrictor of endometrial spiral arteries.
It is luteolytic in women causes loss of luteal cells by increasing apoptotic cell death.
And signal endometrium to initiate molecular events leading to menstruation.
Side effects:
Symptoms mimic dysmenorrhea because of myometrial contraction & uterine ischemia.

PGI2:
PGI2 is the principal prostaglandin of endometrium.
Increases in late pregnancy.
It functions in regulation of blood pressure and coagulation.
Needed for the angiotensin resistance of normal pregnancy.

PGE2 & PGI2 :
PGE2 & PGI2 maintain uterine quiescence by increasing C AMP signaling.
They stimulate adenylcyclase activity in myometrium at 32 to 35wks leading to relaxation of vascular smooth muscle, vasodilatation.
At 39 to 40 wks, regional myometrial contractions in fundus occurs after initiation of parturition.
PGE2 synthesis in renal medulla is markedly increased in late pregnancy and it acts as natriuretic.

Prostaglandin-routes of administration
Prostaglandins- in inducing abortions
Prostaglandins-induction of labor
Cervidril, misoprostol
Prostaglandins- in PPH, uterine atony