1. Growth Hormone and Recombinant Bovine Growth Hormone Stevie

2. Growth Hormone Protein hormone made of ~ 190 amino acids Made in Anterior Pituitary by somatotroph cells

3. Direct Effects of GH Binds to adipocytes and causes them to break down triglycerides and prevents them from accumulating fat in the blood Releases insulin-like growth factor-1 (IGF-1)

4. Indirect Effects of GH Stimulates: – Cartilage cells (chrondrocytes) growth – Myoblasts growth and differentiation – Amino Acid uptake – Protein synthesis

6. Other Effects Keeps blood glucose at healthy levels Prevents insulin from absorbing glucose in tissue Causes creation of glucose in the liver In mature cows, it stimulates lactation

7. GH Secretion Growth Hormone-Releasing Hormone: causes production and release of GH Somatostatin: inhibits release of GH Grehlin: secreted from stomach, binds to somatotrophs and causes secretion of GH

9. Negative Feedback Loop If blood levels of IGF-1 are too high, somatotrophs are suppressed and somatostatin is released GH also circles back to hypothalamus and inhibits release Scientists believe GH has an autocrine effect on somatostatin This leads to GH inhibition

11. Recombinant Bovine Growth Hormone Increases milk production by 10-15% Regulates efficiency of feed conversion to milk rBGH mimics the effects of growth hormone Growth Hormone is a naturally occurring hormone produced in the anterior pituitary

12. How rBGH works Created using recombinant DNA technology The gene sequence for this hormone is injected into e. coli E. coli then produces GH This is purified and injected into dairy cows Broken down once it enters digestive system Called Posilac

13. How rBGH works Cows lactate 305 days after calving, but their peak in lactation is between 45-90 days Farmers administer rBGH just before peak lactation rBGH prevents mammary cell death – Fat is broken down and sent to mammary cells

15. References "Bovine Somatotropin." Wikipedia. Wikimedia Foundation, 09 Jan. 2014. Web. 14 Sept. 2014. Bowen, R. "Growth Hormone." Growth Hormone. Colorado State, 24 Dec. 2006. Web. 14 Sept. 2014.