Diabetes Drug Caused Male Fish To Produce Eggs

Researchers from University of Wisconsin-Milwaukee have found out that male freshwater fish exposed to a diabetes drug have gained the ability to produce eggs.

A study headed by Rebecca Klaper, published in Chemosphere, has shown that Metformin, a drug commonly used to treat Type 2 diabetes mellitus, has been found in freshwater systems in the U.S. and has produced an effect among male freshwater fish, making them able to reproduce. Apart from studying the intersex changes, Klaper also found that those fish exposed to metformin were smaller compared to those not exposed.

The results were a surprise to the researchers since metformin usually targets blood sugar regulation and is not a hormone drug. However, Klaper explained that metformin can also be used to treat hormonal disorder in women called polycystic ovarian syndrome.

Researchers said that the drug could be an endocrine disruptor based on the fish study results. An endocrine disruptor would confuse the body’s complex hormonal system, interrupting normal bodily functions, including reproduction.

The number of people treated for diabetes is increasing in the U.S. and drug residues usually end up in the freshwater systems via sewage treatment facilities. Kapler is still conducting an ongoing study on the levels of metformin found in freshwaters and how it can affect wildlife.

In the study, the researchers collected water samples from Lake Michigan and have found that metformin levels are greater than that of caffeine and are present in almost all the samples tested. “It is the chemical we found in almost every sample and in the highest concentrations compared to other emerging contaminants-even higher than caffeine,” Klaper said in a ScienceDaily report.

The study showed that male fish carried genes related to hormones responsible for egg production. ScienceDaily reports that Kapler is currently studying the effects of metformin in a fish’s genome if exposed to the drug from birth to childhood.

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