Bioassay of insulin

A bioassay of insulin is a laboratory procedure used to measure the biological activity or potency of insulin by observing its effect on living cells or tissues. It’s commonly used to evaluate the efficacy of insulin in regulating glucose metabolism. Here’s an overview of how this is typically done:

Methods of Insulin Bioassay:

1. In Vivo Assays:

   • Rabbit Blood Sugar Test: This classical method involves injecting insulin into a rabbit and measuring the drop in blood glucose levels over time. It was one of the earliest methods used.
   • Mouse Convulsion Test: Mice are used to assess insulin’s ability to lower blood glucose levels until hypoglycemic convulsions occur, which helps gauge its potency.

2. In Vitro Assays:

   • Cell-Based Assays: These assays involve insulin-sensitive cells, such as adipocytes or muscle cells, to measure how insulin promotes glucose uptake, fat synthesis, or other metabolic processes.
   • Radioimmunoassay (RIA): This is a more precise, antibody-based technique to measure insulin levels, although it’s more indirect than observing actual biological effects.

Parameters Assessed:

• Glucose Uptake: Insulin’s primary effect is increasing glucose uptake in tissues, so this is a key measurement.
• Insulin Sensitivity: How sensitive cells or organisms are to insulin can be a marker of potency.
• Onset of Action: The speed at which insulin begins to work.
• Duration of Action: How long insulin continues to lower blood glucose after administration.

Importance:

• Therapeutic Monitoring: Ensures the efficacy of insulin used for diabetes treatment.
• Batch Consistency: Ensures that different batches of insulin have consistent biological activity.
• Research: Helps scientists develop new insulin analogs or therapies for diabetes.