When we examined the associations among the pesticide concentrations, the correlations (Table 4) appeared to be sufficient to apply PCA methods. As shown in Table 1, geometric mean hormone concentrations varied by age and by body mass index. Among the 748 males in the study sample, the average age was 44.8 (SD 0.72) years and 73% were non-Hispanic white. After assessing the correlation among log transformed lipid-adjusted pesticide concentrations using Pearson correlation coefficients, we used PCA methods to estimate eigenvalues for each component using log transformed pesticide concentrations. Linear regression models were built for continuous log transformed sex steroid hormones (dependent variables) using a forward approach beginning with individual models of each lipid standardized pesticide concentration.
Consistent with the findings in the current study, most other studies in males have not found HCB to be related to testosterone (Hagmar, Bjork et al. 2001, Goncharov, Rej et al. 2009, Ferguson, Hauser et al. 2012, Freire, Koifman et al. 2014). Many of the pesticides were highly correlated, with the highest correlation coefficient of 0.88 observed between serum trans-nonachlor and its metabolite oxychlordane. Relative to those without, males with diabetes had higher levels of most of the pesticides except for HCB.
Other studies also suggest that lindane is anti-estrogenic and is able to disrupt the estrus cycle 68,69. When mixed together they may induce estrogenic responses at concentrations lower than those required when each compound is administered alone . Possible effects may be decreased production of GnRH by the hypothalamus (negative feedback system) and of LH and FSH by the pituitary gland. When an endocrine disruptor or one of its metabolites bind and activate the estrogen receptor, the endocrine disruptor will imitate the hormone 17β-estradiol.
Behind each Frontiers journal is an editorial board committed to upholding research integrity and scientific quality The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The original contributions presented in the study are included in the article/supplementary material.
WhileOakes et al. (2002)33, reported nosignificant difference in the serum concentration of testosterone in control animalswhen compared to treated animals, they noticed a severe reduction in testicularweight in some high dose animals with histology showing shrunken tubules with germcell depletion. Three, we found no relationships between 3-PBA, anon-specific metabolite of PYR insecticides, and testosterone levels. This is contrary to the study by Omoike et al. where theyreported a statistically significant negative relationship between DEP andtestosterone when DEP was modeled as either a continuous or categoricalvariable29. However, they reported potentialsuppression of testosterone levels during high season application by comparingtestosterone levels of these applicators during low- and highuse seasons16,17.
The pesticides hexachlorobenzene, mancozeb, and 3,3',4,4'-tetrachloroazoxybenzene may also cause cycle irregularities, such as a decrease in the number of estrus cycles and an increase in the duration of diestrus 96,98,116,117. The pesticides dimethoate, malathion, and sumithion gave similar results107,108 Atrazine, an antagonist of the estradiol receptor, can alter the estrus cyclicity in rats and caused lengthening of the estrus cycle and an increase in the number of days in estrus . Progesterone levels may be decreased by exposure to methoxychlor as well, especially during the estrus phase of the estrus cycle in rats 99,100. Diestrus is the luteal phase of the estrus cycle when the female is not receptive to the male and the progesterone levels are high.
Garry et al. reported no direct relationship between urinary2,4-D and testosterone levels among select applicators in the UnitedStates16,17. After controlling forcovariates, regression results revealed dose-dependent, negative relationshipsbetween urinary 2,4-D (modeled as either a continuous or categorical variable) andtotal testosterone. These location-specific exposure patternscan be explained by different crop production. On the other hand, farmers fromInthaknin were exposed more to chlorophenoxy herbicides (i.e., 2,4-D and alachlor)compared to Pong Yaeng’ farmers.

Gender: Female

Social links