Part A: Secretory Cells and Primary Action of Growth Factors
(i) Insulin-like Growth Factor (IGF)
- Secretory Cells: Primarily secreted by the liver in response to growth hormone (GH) stimulation. Also produced in small amounts by other tissues like skeletal muscles.
- Primary Action:
- Stimulates cell growth, development, and differentiation.
- Promotes protein synthesis in muscle and bone tissues.
- Mediates the growth-promoting effects of growth hormone.
(ii) Platelet-Derived Growth Factor (PDGF)
- Secretory Cells: Released by activated platelets, macrophages, endothelial cells, and smooth muscle cells.
- Primary Action:
- Stimulates proliferation and migration of fibroblasts and smooth muscle cells.
- Crucial in wound healing, blood vessel formation, and tissue regeneration.
Part B: EPO – Erythropoietin
Full Form:
EPO stands for Erythropoietin.
Functions:
- Erythropoietin is a hormone responsible for stimulating the production of red blood cells (RBCs) in the bone marrow.
- It is mainly secreted by the kidneys in response to low oxygen levels (hypoxia) in the blood.
- Helps maintain adequate oxygen transport capacity in the blood by regulating RBC count.
Applications:
- Medical Use:
- Treatment for anemia, especially in chronic kidney disease (CKD) patients.
- Used in cancer patients undergoing chemotherapy to boost RBC count.
- Athletic Misuse:
- Sometimes misused by athletes for blood doping to enhance endurance. This is banned in sports.
Conclusion
Growth factors like IGF and PDGF play vital roles in development and tissue repair. Erythropoietin is a life-saving hormone used in anemia treatment. Understanding these molecules is essential in biochemistry, medicine, and clinical applications.