Biology in the Laboratory

Biotech Labs and Food

What is bovine growth hormone, and why is it so controversial?

One of the earliest applications of biotechnology was the genetic engineering of a growth hormone produced naturally in the bovine pituitary. The recombinant Bovine Growth Hormone (rBGH), or Bovine Somatotropin (rBST), a genetically engineered hormone manufactured by Monsanto, was reported to increase milk production in lactating cows. Using biotechnology, scientists bioengineered the gene that controls bovine growth hormone production into E. coli bacteria, grew the bacteria in fermentation chambers, and thus produced large quantities of hormone. The bioengineered hormone, when injected into lactating cows, resulted in an increase of up to 20 percent in national milk production. Using bovine GH, farmers were able to stabilize milk production in their herds, avoiding fluctuations in production levels.

But bovine growth hormone is controversial for those who drink cow’s milk, especially infants. The hormone actually makes the cow produce more milk than it naturally would, thus reportedly making the cow more susceptible to disease. This is attached to a concern that the amount of antibiotics given to the cow—if it does become diseased— would be passed along to the humans who consume the milk. Still another claim is that the hormone stimulates another hormone called Insulin-Like Growth Factor-1, or IGF-1, which promotes cell division and is associated, in this instance, as a possible impetus for cancer growth.


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