The first human hormone produced by recombinant DNA technology is:

Options

A. Progesterone
B. Insulin
C. Estrogen
D. Thyroxin

Answer

To solve the question regarding the first human hormone produced by recombinant DNA technology, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the first human hormone that was produced using recombinant DNA technology. This technology involves the artificial manipulation of DNA to produce desired proteins or hormones.

2. **Identifying the Options**: The options provided are progesterone, insulin, estrogen, and thyroxine. We need to determine which of these hormones was the first to be produced using recombinant DNA technology.

3. **Recalling Historical Context**: Insulin was the first human hormone to be successfully produced using recombinant DNA technology. This milestone occurred in the early 1980s when scientists were able to clone the human insulin gene and express it in bacteria.

4. **Understanding Insulin Production**: Insulin is a hormone that regulates blood sugar levels and is secreted by the pancreas. The recombinant DNA technology involves inserting the insulin gene into a vector (a DNA molecule used to deliver genetic material into cells), which is then introduced into a host organism, typically E. coli bacteria. The bacteria then produce insulin, which can be harvested and purified for medical use.

5. **Conclusion**: Based on the historical context and the understanding of recombinant DNA technology, the correct answer to the question is **insulin**.

### Final Answer:
The first human hormone produced by recombinant DNA technology is **insulin**.

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