2. Presented by: Aiman
Roll no# UOC-BSZOL-F2020/016
Department of Zoology
Session: 2020-2024
Subject: Endocrinology
Instructor Name: Dr. Syeda Nadia Ahmad
Topic: Placental Lactogen Hormone
4. Introduction:
Placental lactogen(PL) also known as human
chorionic somatomammotrophin, is a
hormone produced during pregnancy
Origin:
Syncytiotrophoblast cells of the placenta
Structure:
Similar to GH & prolactin
Single chain Polypeptide
(191 amino acids)
(Handwerger & Freemark, 2000)
Figure:1.Crystalline structure
of placental
lactogen(https://en.m.wikipedia.o
rg/wiki/File:1Z7C.pdb.png)
5. Regulation of synthesis and secretion:
Synthesize by syncytiotrophoblast cells
Detected at 6th week of gestation
Peak conc. at 30thweek (5-7ug/ml)
1g/day near term
Positively correlated with placental mass
Minute amount enter in fetal circulation
(Sibiak et al., 2020)
Figure:2.PLlevel during pregnancy
https://images.app.goo.gl/nWTxW17q7hB
2f3g69
6. Regulation of synthesis and secretion:
• Specific hormonal & metabolic
regulatory factors are unknown
• Prolonged fasting &hyperglycemia
decrease PL secretion
• Epidermal growth factor increase hPL
release
(Handwerger & Freemark, 2000) Figure.3:syncytiotrophoblast
cells of placenta secrete PL
https://images.app.goo.gl/Yz2t7i4f
d1apMNvf9
9. ➢ Role in
Pancreatic Beta
Cells:
Promotes β-cell
proliferation
Inhibit apoptotic
activity
Protect against
glucolipotoxicity
10. Figure.4:Mechanisms of the biological activity of
placental lactogen (PL) in pancreatic β-cells.
https://images.app.goo.gl/BTeKW1WF4ccJf4ay9
Mechanism
PL bind with PRL
receptors and stimulate
intracellular pathway
inhibit apoptotic activity
by phosphorylation of
protein kinase B
increase expression of
BCL-XL
(Sibiak et al., 2020)
12. PL role in early organogenesis:
9.5 day rat embryo were cultured in vitro in the presence&
absence of PL for 48 h by karabulut et al
Embryos treated with PL show improved parameters:
morphological score
yolk sac diameter
crown-rump length
somite number
Embryonic & yolk sac protein content
(KARABULUT et al., 2002).
13. PL as a Gestational Marker of Fetal Development:
Higher PL levels
result in better fetal
growth
PL stimulates IGF
production and plays
a role in the
regulation of fetal
growth
(Sibiak et al., 2020)
Figure .5:The influence of increased blood PL levels
on tissues of the developing fetus.
https://images.app.goo.gl/558hcToe2K9zi
14. Metabolic actions of PL in mother & fetus during
gestation:
Figure.6:Metabolic effect of PL.https://images.app.goo.gl/rjaBCXiXCc5V6BvB7
16. How PL cause gestational diabetes?
PL stimulate glucose
production
PL cause insulin
resistance due to which
blood glucose level
increase that leads to
gestational diabetes
(Sibiak et al., 2020).
Figure.7:Higher PLlevel leads to gestational
diabetes
https://images.app.goo.gl/jhxVnznmp1BCiqgRA
18. How to deal with gestational diabetes :
Eat right carbohydrates
Eat healthy breakfast
Take prescribed medicine
Monitor blood sugar level
opt for sugar free diet
Sleep well
Avoid sugary drinks and
desserts Figure.8:How to deal with gestational diabetes.
https://images.app.goo.gl/TKcVNaEsju74EzMP6
19. How placental lactogen cause fetal Macrosomia:
PL cause insulin
resistance that leads
to high blood
glucose level in
mother
Transport extra
glucose to fetus
Cause baby to put
on extra weight Figure. 9:fetal macrosomia
https://images.app.goo.gl/L7oH
1P77Px9r5a5K9
20. Conclusions:
In summary, current evidence strongly suggests that
Placental Lactogen is a multifunctional hormone crucial
for fetal growth and maternal adaptations.
PL ensure the optimal supply of nutrients to the fetus and
utilization of the nutrients by fetal tissues.
(Sibiak et al., 2020).
21. References:
• Handwerger, S., & Freemark, M. (2000). The roles of placental growth hormone and placental
lactogen in the regulation of human fetal growth and development. Journal of Pediatric
Endocrinology and Metabolism, 13(4), 343-356.
• KARABULUT, A. K., Layfield, R., & Pratten, M. K. (2002). Growth promoting effects of
human placental lactogen during early organogenesis: a link to insulin-like growth factors. The
Journal of Anatomy, 198(6), 651-662.
• Sibiak, R., Jankowski, M., Gutaj, P., Mozdziak, P., Kempisty, B., & Wender-Ożegowska, E.
(2020). Placental lactogen as a marker of maternal obesity, diabetes, and fetal growth
abnormalities: current knowledge and clinical perspectives. Journal of Clinical Medicine, 9(4),
1142.