p-tert-Octylphenol (OP) is a degradation product of alkylphenol ethoxylates. OP is an endocrine disruptor known to bind to the estrogen receptor; however, effects on males are controversial. The objective of this study was to evaluate the effects of chronic exposure to OP on male reproduction. Adult Sprague-Dawley rats were administered OP for 60 d, representing 1.5 cycles of spermatogenesis. Experimental groups included a vehicle control, and three doses of OP (25, 50, or 125 mg/kg body weight [bw]) administered daily by gavage. There was a significant decrease in body weight in the 125-mg/kg group after 60 d of treatment. Both testicular and epididymal weights and histology were not altered by treatment with OP at any of the doses administered. There were no marked differences in cauda epididymal sperm counts at any doses; however, total percent sperm motility was significantly lower in rats exposed to the intermediate dose (50 mg/kg bw). There was an increase in percent static sperm cells in all OP-treated groups, with the intermediate dose (50 mg/kg) displaying a significantly higher proportion of static cells relative to untreated controls. Caput epididymal sperm motility was unaltered by OP treatment. Gene expression profiles of testes from control and high-dose-exposed rats indicate that 14 genes were modulated by at least twofold, although these changes were not statistically significant. Taken together, results from this study indicate that OP treatment of adult rats does not appear to exert major effects on male reproductive endpoints at relevant environmental exposure doses.
There is general concern that persistent organic pollutants (POPs) found in the environment, wildlife, food, water, house dust, human tissues, and fluids may alter normal human physiologic activities (e.g., fetal development, immune and endocrine systems). Although the levels of some POPs [polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs)] in these matrices have decreased after their ban, others [polybrominated diphenyl ethers (PBDEs)] have increased in recent years.To determine the longitudinal trend of specific POPs in human fetal tissues for risk assessment purposes.We analyzed early to mid-gestation fetal liver (n = 52) and placental (n = 60) tissues, obtained after elective abortions during 1998-2006, for selected PBDEs, PCBs, and OCs using gas chromatography-mass spectroscopy.Total PBDEs in fetal liver increased over time (mean +/- SE: 1998, 284.4 +/- 229.8 ng/g lipid; 2006, 1,607.7 +/- 605.9; p < 0.03), whereas placental levels were generally lower, with no clear trend. Low levels of PCBs and OCs varied yearly, with no evident trend. The major analytes in 1998 were OCs (liver, 49%; placenta, 71%), whereas the major analytes in 2006 were PBDEs (liver, 89%; placenta, 98%). The 1998-2006 tissue PBDE congener profile is similar to that of DE-71, a commercial primarily pentabrominated diphenyl ether mixture manufactured in North America.Although commercial production of penta- and octa-brominated diphenyl ethers in North America was halted in 2004, their concentrations in fetal liver and placenta are now greater than the tissue burdens for the analyzed OCs and PCBs. Our findings also demonstrate that PBDEs accumulate within the fetal compartment at a very early stage in gestation.
Possible health benefits and potential adverse effects of dietary phytoestrogens are discussed. Moreover, data from a 16-week rat study to investigate the effects of the addition of graded levels (0, 50,100,200 and 400 mg/kg diet) of soybean isoflavones to a casein control diet on growth, plasma total cholesterol, plasma isoflavones and length of estrus cycle are reported. An isoflavones-rich extract (Novasoy) and a soy infant formula were used a source of dietary isoflavones. Initial analyses revealed a lower body weight in male rats fed the highest two levels of isoflavones. There was a dose-related increase in the levels of plasma isoflavones. The plasma data showed that the absorption of isoflavones from formula was lower than that from Novasoy. There was also a dose-related increase in the length of the estrus cycle in female rats. The cycle in rats fed the formula diet was , however, shorter than that in those fed the Novasoy diet providing the same amount of isoflavones. This suggested differences in the potency based on the source of isoflavones.
The aim of this study was to compare the development and metabolic activity of cultured murine and bovine embryos in 2 standard media (HAM F-10 and RPMI) in the presence or absence of bovine uterine flushings. Murine morulae (n = 653) and day 7 bovine embryos (n = 273) were cultured for 18 h or 36 h in either HAM F-10 or RPMI in the presence or absence of bovine uterine flushings. After culture, the development, quality, and metabolic activity (glucose utilization or methionine uptake and incorporation) of embryos was assessed. It was found that HAM F-10 (without uterine flushings) was a more suitable medium than RPMI for optimal development and metabolism of murine and bovine embryos. Poor quality and development, as well as decreased metabolism, were evident after culture of murine embryos in RPMI; in contrast, this medium had no adverse effects on bovine embryos in culture. Supplementation of HAM F-10 with bovine uterine flushings improved the growth of murine embryos and the protein synthesis (as measured by an increased methionine incorporation) for both murine and bovine embryos. However, supplementation with bovine uterine flushings could not overcome deficiencies of an inappropriate medium (RPMI) for murine embryos. Supplementation of a well-defined culture medium with uterine flushings increased metabolism of embryos in culture, and thus might help to increase pregnancy rates after transfer of such embryos to recipient cows.
Abstract During the luteal phase in the cow, a first-wave dominant follicle grows to reach ovulatory size, but then ceases to grow, becomes no longer dominant and enters a phase of slow regression. During this growth transition, the concentration of oestradiol has been shown to decrease in follicular fluid. The objective of this study was to determine if follicular fluid oestradiol concentrations are regulated by the activity of three major steroidogenic enzymes, namely P450-aromatase (P450-arom), 3β-hydroxysteroid dehydrogenase/Δ5–Δ4 isomerase (3β-HSD) and 17α-hydroxylase C-17,20 lyase cytochrome P450 enzyme (P450–17α) measured in granulosa and theca cells isolated from individual first-wave dominant follicles. Follicle growth and state of dominance was assessed by ultrasonography and follicles were classified as growing-dominant (GD, n =6), non-growing-dominant (NGD, n =8) or non-growing-non-dominant (NGND, n =6). Mean follicular fluid concentrations of oestradiol were higher in GD than in NGD or NGND follicles (511 ± 98 versus 136 ± 16 and 20 ± 11 nmol/l respectively). Oestradiol was not correlated with P450-arom in any of the three groups. In GD follicles, oestradiol was positively correlated with pregnenolone concentration but neither was correlated with granulosa or theca 3β-HSD activity or with theca P450–17α activity. In NGD follicles, oestradiol was negatively correlated with theca 3β-HSD activity and pregnenolone was negatively correlated with granulosa 3β-HSD activity. In NGND follicles, oestradiol was positively correlated, and pregnenolone was negatively correlated with theca 3β-HSD and P450–17α activities. These studies demonstrated that pregnenolone supply is the principal regulating factor of oestradiol output during follicle dominance and during the loss of dominance but that the levels of P450–17α and 3β-HSD activity become rate-limiting when the follicle is no longer dominant. Journal of Endocrinology (1996) 149, 233–242
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