Insulin is a naturally occurring hormone made by the pancreas that helps our body use or store the glucose (sugar) it gets from food. For people with diabetes, either the pancreas does not make enough insulin to meet the body's requirements, or the body cannot properly use the insulin that is made.
The yellow color in normal urine comes from a substance known as urochrome. Urochrome is also known as urobilin and is the result of hemoglobin breakdown. Hemoglobin is the protein in red blood cells that enables oxygen to be taken around the body.
The yellow tinge in human urine is observed due to the presence of urobilin in it, which is a yellow linear tetrapyrrole. Urobilin comes from bilirubin, after it is broken down in the liver; which is originally derived after breaking down heme (combination of hemoglobin, myoglobin, and the cytochromes).