Scientists have developed a transgenic cow capable of producing human insulin in its milk, a breakthrough led by Professor Matt Wheeler from the University of Illinois. By leveraging the efficiency of the mammary gland, the team introduced human DNA coding for proinsulin into cow embryos, resulting in the birth of a transgenic cow. Unlike past methods, this approach specifically targets mammary tissue to avoid human insulin in the cow’s blood. Despite initial difficulties with impregnation, lactation was induced using hormones, leading to the cow naturally processing proinsulin into active insulin in its milk.

The cow produces insulin and proinsulin at a significant rate, although exact quantities remain uncertain due to the hormone-induced lactation’s effect on milk volume. However, calculations suggest that each gram of insulin produced could potentially yield thousands of insulin units, with the potential for substantial production given a cow’s daily milk output.

The team plans to clone the cow for further breeding and eventual establishment of a transgenic herd. They envision this method could outpace existing insulin production techniques using yeast and bacteria. Despite the need for specialized facilities, they believe the established dairy industry can readily accommodate the process. The goal is to alleviate insulin scarcity and high costs associated with diabetes treatment, potentially revolutionizing insulin production on a global scale.