Even short-term use of the world's most popular herbicide, Roundup, could lead to a range of health problems including steroidal hormonal imbalances, says a new study.
Published in the journal Toxicology Reports, Medhamurthy Rudraiah and Aparamita Pandey — both from Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science (IISc), Bengaluru — have found that Roundup, the best-selling herbicide, produced and manufactured by Monsanto, can cause imbalances in the synthesis of steroid hormones in male rats.
Previous studies have linked the herbicide — which contains glyphosate — to diseases such as Parkinson's, infertility and skin cancer. The herbicide kills weeds by inhibiting enzymes that synthesise aromatic amino acids essential for plant development. As humans and mammals do not have the enzymes, the herbicide was marketed as being a non-toxic alternative to chemicals.
The IISc researchers subjected male rats to varying levels of Roundup exposure — the minimum being just 10 mg per kg of the rat while the maximum dosage was 250 mg per kg. The rats were orally administered the weed killer for two weeks.
The outcome of the experiment is cause for concern: male rats were seen with decreasing testosterone production (which affects sexual functions) as well as Adreno-Cortico-Tropic Hormone from the pituitary gland (which affects the body’s ability in maintaining normal glucose and fat metabolism).
Both testosterone and corticosterone were down by more than 33 per cent even at the lowest doses of 10 mg and 50 mg daily. The RNA expression of receptors for cholesterol uptake (low density lipoprotein receptor) was found to be significantly lower, notes the study. In effect, the rats seem to eat less as the course continued. Those exposed to 250 mg per day ate less than half the food as was eaten by the control group, while their body weight decreased by 33 per cent in just two weeks. Even rats administered just 10 mg of the herbicide daily saw a marginal six per cent reduction in weight. “It is therefore highly possible that the herbicide affects other endocrine glands as well…and these results were seen in just two weeks of exposure. The herbicide must be investigated as the weed killer is used extensively”, says Ms. Aparamita, first author of the study.
