Possible Side Effects of 17β-estradiol and Tamoxifen Treatment

Treatment with estrogens, mainly in women, and selective estrogen modulators (SERMS), which are also interesting for the average juicer, may yield hitherto unknown metabolic side effects. Scientists from Portugal (Moreira. 2010) have found that both, tamoxifen as well as estrogen treatment influence the oxidative capacity of mitochondria:

Fig. 1. Effects of E2 and/or TAM treatments on glutathione levels of liver, heart and brain mitochondria. (Moreira. 2010)

In spite of the distinct effect on glutathione levels, their effect on lipid peroxidation appears to be contrary:

TBARS levels were used to determine the extension of lipid peroxidation (PX) induced by the pro-oxidant pair ADP/Fe²⁺. Fig. 3A shows that liver mitochondria isolated from E2 + TAM females in the presence of ADP/Fe²⁺ produced significantly lower levels of TBARS when compared with liver mitochondria isolated from the other groups of experimental animals. No significant alterations were observed in brain mitochondria (Fig. 3B). Heart mitochondria were not tested because the amount of mitochondria obtained per heart did not allow us to test all the parameters including lipid peroxidation.

Nevertheless, the scientists come to the conclusion:

Although liver mitochondria is mildly affected by E2 treatment, the most deleterious effects are observed in heart mitochondrial function suggesting that estrogens should not be recommended, at least, to individuals with cardiac problems. Concerning TAM treatment, our results indicate that this agent may interfere with liver and brain mitochondrial function although the degree of toxicity would be dependent on predisposing conditions as the general metabolic condition of the patient. The data from the present manuscript indicate that further studies are thus necessary to correctly evaluate the toxicity of HRT on the different organs and determine the risk/benefit for each individual.