no one knows :P
because the gene to make insulin isn't expressed
Insulin is not produced by skin cells.
A mutation in a person's skin cells would be least likely to impact their ability to produce insulin as insulin is primarily produced by pancreatic cells. Skin cells are not directly involved in insulin production or regulation.
because they haven't got the right genes
Insulin is made in the pancreas, not by blood cells. They have other jobs to do.
they make skin
Specialized pancreas cells, called beta cells, produce and release insulin. Insulin plays a crucial role in regulating blood sugar levels by promoting the uptake of glucose from the blood into cells for energy utilization or storage.
Insulin-independent cells are primarily muscle cells and nervous system cells. These cells do not rely on insulin to take up glucose for energy. Instead, they have insulin-independent glucose transporters that allow them to take in glucose from the bloodstream without the need for insulin.
Insulin formed by the Golgi apparatus in insulin-producing cells leaves those cells by exocytosis. This process involves the insulin-containing vesicles fusing with the cell membrane and releasing insulin into the bloodstream.
The pancreas produces a variety of hormones, two being insulin and glucagon, these hormones are produced by groups of cells called the islets of langerhans.
The beta cells of the pancreas produce insulin and C-peptide, a byproduct of insulin. Source: Wikipedia
Bacterial cells are commonly used in biotechnology to produce insulin using exogenous DNA. The exogenous DNA encoding for human insulin is introduced into the bacterial cells, which then serve as a host to produce the insulin protein through the process of genetic engineering.