Roundup endocrine distuptor

March 2012

Two decades ago, scientists began to report a disturbing drop in human sperm quantity and quality, and a rise in testicular cancers. The blame for this has been pinned firmly on our modern exposure to chemicals pollutants. Indeed, due to the nature of its function which involves a hormone-linked cell-proliferation at a huge scale and speed, reactions in the testis have become recognised as a uniquely sensitive monitor for biologically disruptive materials.

This principle was used in an early scientific safety study on Roundup Ready soya, genetically transformed to tolerate Roundup herbicide. When mice and their male offspring were fed GM soya, analyses of the cells of the developing testes gave no indication of toxic effects (Brake and Evenson). The study was later used to 'disprove' other GM soya feeding studies which suggested harm.

However, scientific evidence of another risk linked to Roundup Ready soya has been building steadily: the problem is not so much the GM soya as the Roundup.

'Roundup' is any one of a number of commercial preparations. All of these contain the chemical 'glyphosate' as their active, herbicidal, ingredient. However the bulk of the total volume of Roundup consists of other (sometimes secrete) chemicals: these allow it to be applied more efficiently, to penetrate the plant and cell protective layers, and to kill more quickly. GM plants can accumulate the glyphosate component without harm, but the identity, fate and toxicity of all the other chemicals are mysteries.

Industry 'safety' studies submitted to the regulators have successfully focused on glyphosate alone and allowed Roundup to become known as the friendliest weed-killer on the market. Evidence is now accumulating that the authorities were duped into ignoring the true nature of what they were regulating.

Current reviewers can cite more than ten published studies which establish a negative impact of Roundup on mammalian reproduction. It has been documented that Roundup is contaminating the air and groundwater, it’s in the homes and bodies of farm-workers, and in their food. Roundup is now described as a “potent endocrine disruptor” because of its ability to interfere with a key enzyme involved in male hormone (testosterone) production. The result can be significant disturbances in sperm-producing tissues, in the masculisation processes, and in sexual behaviour. Actual effects are dependent on the dose and on the precise developmental stage at which exposure occurs (for example, whether it is maternal, gestational, or pre-pubertal), but all are potentially damaging to fertility. Interestingly, body and organ weights, which are the main parameters measured during standard GM-feeding tests, are not affected.

Central to the concept of Roundup safety has been the myth that dietary glyphosate is inert and is totally eliminated from the body in the faeces and urine. It has been pointed out, however, that the tests which established this are based on single doses, of which 99% is eliminated after seven days. The 1% still present remains in the gut and in the bones. Serious questions about the bio-accumulation of glyphosate during chronic exposure (and on-going retention of 1% of that exposure) have not been tackled.

Scientists are, however, beginning to investigate effects of Roundup as opposed to glyphosate, and also of glyphosate's main derivative AMPA (aminomethylphosphonic acid).

Using rat testis cells in culture as a model, they established that, while different testicular cell-types vary in sensitivity, short-term exposure to Roundup and glyphosate at levels ranging from those found in urine (1 ppm) to those used in agriculture (10,000 ppm) were potentially harmful: higher concentrations caused cell death, and even at the lowest concentration, endocrine disruption was evident (note that the maximum residue level allowed in the US is 400 ppm, or four-hundred times the level found to cause a reaction). The authors also pointed out the implication that, since hormones can trigger changes in gene expression which can be passed on to subsequent generations, Roundup and glyphosate could well effect future generations.

The above mentioned Brake and Evenson study, which reported no testicular effects in mice fed Roundup Ready soya might suggest that the Roundup and glyphosate in GM food can be handled safely by the body. However, the soya chow used in this experiment came from a commercial crop from the year 2000, long before the current superweed epidemic caused an exponential increase in the rate and frequency of spraying with Roundup, and before the modern super-lethal Roundup formulations came on the market, and before the decades of year-on-year Roundup applications and environmental accumulation had happened. Roundup and glyphosate residues in the chow were not recorded. The experimental mice may not have been exposed to any Roundup or glyphosate, and the experiment may have no relevance to our present-day GM soya.


At the moment we can only speculate on how much Roundup or glyphosate is in our bodies. However, the concentrations used in the cell culture experiment are very relevant to our possible exposure levels.

It's time to call for a ban on all use of Roundup and glyphosate until chronic exposure is proved harmless, especially to all reproductive paramenters, to bones, to the digestive tract and its microbial flora, and until environmental and food contamination levels are monitored and found to be safe.


  • Émilie Clair, et al., 2012, A glyphosate-based herbicide induces necrosis and apoptosis in mature rat testicular cells in vitro, and testosterone decrease at lower levels, Toxicology in Vitro 26
  • Marco Aurelio Romano, et al., 2011, Glyphosate impairs male offspring reproductive development by disrupting gonadotropin expression, Archives of Toxicology,
  • R. M. Romano, et al., 2010, Prepubertal exposure to commercial formulation of the herbicide glyphosate alters testosterone levels and testicular morphology, Archives of Toxicology, 2010
  • D. G. Brake and D. P. Evenson, 2004, A generational study of glyphosate-tolerant soybeans on mouse fetal, postnatal, pubertal and adult testicular development, Food and Chemical Toxicology 42
  • Dr. Eva Sirinathsinghji, Glyphosate ills Rat Testis Cells, Institute of Science in Society Report, 27.02.12

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