Soy but not bisphenol A (BPA) or the phytoestrogen genistin alters developmental weight gain and food intake in pregnant rats and their offspring

Abstract

Endocrine disrupting compounds (EDCs) are hypothesized to promote obesity and early puberty but their interactive effects with hormonally active diets are poorly understood. Here we assessed individual and combinatorial effects of soy diet or the isoflavone genistein (GEN; administered as the aglycone genistin GIN) with bisphenol A (BPA) on body weight, ingestive behavior and female puberal onset in Wistar rats. Soy-fed dams gained less weight during pregnancy and, although they consumed more than dams on a soy-free diet during lactation, did not become heavier. Their offspring (both sexes), however, became significantly heavier (more pronounced in males) pre-weaning. Soy also enhanced food intake and accelerated female pubertal onset in the offspring. Notably, pubertal onset was also advanced in females placed on soy diet at weaning. Males exposed to BPA plus soy diet, but not BPA alone, had lighter testes. BPA had no independent effects.

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“…Alternatively, lower levels of TBBA found in the urine of lactating dams could be a result of simple dilution, as both gestating and lactating dams were allowed water ad libitum. In fact, there is evidence that lactating Sprague Dawley rats drink, on average, more water than their gestating counterparts (Cao et al, 2015;Slone et al, 2012). This is also supported by the high variability in urinary TBBA levels, indicating differential water intake (Fig.…”

Interaction of bisphenol A (BPA) and soy phytoestrogens on sexually dimorphic sociosexual behaviors in male and female rats

“…Complete study design details are described in a prior study in which we used the same animals (Cao et al, 2015). Briefly, 54 pairs of Wistar rats were obtained and their offspring tested for these experiments.…”

“…The soy diet was a custom diet (Harlan Laboratories, Madison, WI) with maximum similarity to Teklad 2020 with isoflavone levels ~400 mg/kg diet. Effects on growth, body weight, age at puberty and other developmental parameters for these animals are detailed in a prior publication (Cao et al, 2015). …”

“…BPA (Sigma-Aldrich, St. Louis, MO) was administered via drinking water, as described previously (Cao et al, 2012), at 2 mg/L of water; to produce serum levels in the human range (<4 ng/ml serum) (Cao et al, 2015). GEN levels (dams and pups) in the soy-fed group were 3 – 31 ng/ml (Cao et al, 2015).…”

Comparison of endpoints relevant to toxicity assessments in 3 generations of CD-1 mice fed irradiated natural and purified ingredient diets with varying soy protein and isoflavone contents

“…Andreoli et al (2015) also reported that feeding adult male Wistar rats a low phytoestrogen diet induced obesity and impaired glucose metabolism. Conversely, exposure of Wistar rats to a soy meal-containing diet during development has been reported to result in increased adult body weight in males, but not females (Cao et al, 2015), while developmental exposure of Sprague-Dawley rats to genistein was reported to result in obese adult females, but not males (Strakovsky et al, 2014). Lifetime exposure of Sprague-Dawley rats to 500 ppm, but not 5 or 100 ppm, genistein reduced body weight gain in the F 1 and F 2 generation females and in the F 1 generation males (National Toxicology Program, 2008a).…”