Prostaglandins

2,581 views

Published on

0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
2,581
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
411
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Prostaglandins

  1. 1. By H.Khorrami Ph.D. http://khorrami1962.spaces.live.com khorrami4@yahoo.com
  2. 2.  EPA(Eicosa Pentaenoic Acid)  DHA( Docosa Hexaenoic Acid)  Polyunsaturated FA
  3. 3. PL-A2
  4. 4.  PGE2 →+GnRH →+LH  Indomethacin in follicular phase → block ovulation  Catecholamines →+PGE2 →+GnRH  Estrogen →+PGE2 →+ LH
  5. 5.  PGE2 stimulate GnRH in response to catecholamines  PGE2 stimulate LH in response to estrogen  So indomethacin blocks ovulation
  6. 6.  LH →+cAMP →+PGF2α , PGE2 in follicles  PGF2α as luteolysis factor  Cyclooxygenase inhibitor → prolong corpus luteum life  PGF2α → uncoupling of LH receptor from cAMP ( in minutes) → decrease steroidogenesis / loss of LH receptor ( in hours)  Progesterone secretion stimulated by PGE2 & inhibited by PGF2α  Adenosin ( a purine) amplificate LH action  The balance of adenosin/ PGF2α is important for luteal lifespan
  7. 7.  LH stimulates PGF2α & PGE2  PGF2α is a luteolysin factor  In minutes uncoupling LH receptor from cAMP  In hours loss of LH receptor  PGE2 stimulate progesterone secretion by granulosa cells  PGF2α inhibit progesterone secretion by granulosa cells
  8. 8.  PGE2 inhibits spontaneous contraction  PGF2α stimulate tubular contraction (isthmic region)  Progesterone enhance PGE2 effect
  9. 9.  PGF2α receptor predominantly in isthmic region  PGE receptor predominantly in ampulatory region  PGF2α stimulate tubular contractility  PGE2 inhibit spontaneous contraction  Enhanced by progesterone
  10. 10.  Infertile & took contraceptive …. contraction in response to PGE2  Gravid uterus…. contraction in response to PGE2 & PGF2α  Non-gravid. . . .diminished response 
  11. 11.  Response depends on various stages  Nonpregnant generally is stimulated by PGE2 & PGF2α  lower sensitivity at the time of ovulation  PGE2 → uterine contraction(in fertile & contraception)  Diminished response in non gravid uterine  PGI2 a potent vasodilator and anti-PGF2α  At mid-gestation → PGF2α → tonic contraction  Estrogen stimulate gap junction formation in myometrium  Progesterone inhibit gap junction formation in myometrium  At term → decline in progesterone → gap junction → cyclic contractions
  12. 12.  Estrogen stimulate gap junctions  Progesterone inhibit gap junctions  Gap junction is need for cyclic contraction  Otherwise tonic contraction  Endometrium:  During proliferation:  Direct relation between PGE & estradiol  Constriction of spiral arteriols  Suppression of PG synthesis during pregnancy
  13. 13.  In pregnancy: less collagen compared with non- pregnant  Decrease in Prog/est ratio ….. More PGE2  Disperse of collagen fibers and replaced with fluid & glycosamin glycan  Make cervix soften  PGE2 dilate cervix at the time of delivery
  14. 14.  Inhibits prolactin  Inhibits release of OT  Bind to glucocorticoid receptors on mammary gland  After 34th week…cortisol↑ & CBG↓  As a result ..hCG↓…progesterone↓.►OT↑  Secretion of placental estrogen↑  Sensitivity of uterus to PGF2α↑  Increase pulmonary surfactant  To assist fetus of hypoxia; increase glycogen storage in:  SK.M, heart, liver  PGF2α : control hemorrhage after delivery
  15. 15.  In fetus:  Programmed change in HT ››  Increase ACTH ››  Increase cortisol ››  Decrease transcortin ››  Decrease placental progesterone ››  Increase estradiol, OT & PGF2α  PGF2α.... Increase IP3….increase Cain ››  Myometrial contraction
  16. 16.  PGE2 . . . . . . Apnea in newborn  PGE2 . . . . . . Lower the resistance of pulmonary vessels  PGE2 . . . . . Stimulate fetal breathing  PGE2 & PGI2 . . . . . Preventing D.A. closure  PGs increase in amniotic fluid during labour
  17. 17.  LPA: dilate microvasculature  LPA & LPB: inhibit cytotoxic effects of NK cells
  18. 18.  From 5-HPETE  LTD4….. in anaphylaxia  LTB4…… in chemotactic activity
  19. 19. Type Receptor Function PGI2 IP vasodilation inhibit platelet aggregation bronchodilatation EP1 bronchoconstriction GI tract smooth muscle contraction EP2 bronchodilatation GI tract smooth muscle relaxation vasodilatation EP3 ↓ gastric acid secretion PGE2 ↑ gastric mucus secretion uterus contraction (when pregnant) GI tract smooth muscle contraction lipolysis inhibition ↑ autonomic neurotransmitters ↑ platelet response to their agonists and ↑ atherothrombosis in vivo Unspecified hyperalgesia pyrogenic PGF2α FP uterus contraction bronchoconstriction
  20. 20.  Calcium-independent isoform in macrophages  Calcium-dependent isoform in endothelial cells (eNOS)  Neuronal tissues (nNOS)  acts as a signal for the development and shaping of neuronal cells and their activity  control of blood supply to the brain in response to metabolic demands  Synaptogenesis

×