Paraben esters: review of recent studies of endocrine toxicity, absorption, esterase and human exposure, and discussion of potential human health risks

This toxicology update reviews research over the past four years since publication in 2004 of the first measurement of intact esters of p-hydroxybenzoic acid (parabens) in human breast cancer tissues, and the suggestion that their presence in the human body might originate from topical application of bodycare cosmetics. The presence of intact paraben esters in human body tissues has now been confirmed by independent measurements in human urine, and the ability of parabens to penetrate human skin intact without breakdown by esterases and to be absorbed systemically has been demonstrated through studies not only in vitro but also in vivo using healthy human subjects. Using a wide variety of assay systems in vitro and in vivo, the oestrogen agonist properties of parabens together with their common metabolite (p-hydroxybenzoic acid) have been extensively documented, and, in addition, the parabens have now also been shown to possess androgen antagonist activity, to act as inhibitors of sulfotransferase enzymes and to possess genotoxic activity. With the continued use of parabens in the majority of bodycare cosmetics, there is a need to carry out detailed evaluation of the potential for parabens, together with other oestrogenic and genotoxic co-formulants of bodycare cosmetics, to increase female breast cancer incidence, to interfere with male reproductive functions and to influence development of malignant melanoma which has also recently been shown to be influenced by oestrogenic stimulation. Copyright (C) 2008 John Wiley & Sons, Ltd.

The phenology and potential for self-pollination of two Australian monoecious fig species

In this preliminary study, the reproductive phenology of two monoecious fig species, Ficus racemosa and F. rubiginosa, was examined in tropical Australia. Syconia (inflorescences) occurred on both species all year round, but pre-floral and interfloral syconia were much commoner than the wasp-receptive and wasp-emitting phases in both species. The temporal overlap of the wasp-receptive and wasp-emitting phases on a single tree indicated that self-pollination was possible in both species and that pollinators may sometimes persist through multiple generations on one tree. This sexual phase overlap was commoner in F. rubiginosa than in F racemosa. The two species also differed in their general within-tree asynchrony, with a higher diversity of phases on F. rubiginosa than on F. racemosa. The time from syconium initiation to ripening was very similar in F. rubiginosa (mean = 48.51 days) and F. racemosa (mean = 43.53 days). However, there was much more variation within and between trees for F. rubiginosa. In addition, the wasp-receptive phase was found to last up to 5 days (rnean = 4.38) in F. rubiginosa. Such longevity should contribute substantially to local pollinator population persistence. Future work should use genetic studies to determine whether self-pollination is common in these fig species.

Identification of potential mechanisms of toxicity after di-(2-ethylhexyl)-phthalate (DEHP) adult exposure in the liver using a systems biology approach

Phthalates are industrial additives widely used as plasticizers. In addition to deleterious effects on male genital development, population studies have documented correlations between phthalates exposure and impacts on reproductive tract development and on the metabolic syndrome in male adults. In this work we investigated potential mechanisms underlying the impact of DEHP on adult mouse liver in vivo. A parallel analysis of hepatic transcript and metabolic profiles from adult mice exposed to varying DEHP doses was performed. Hepatic genes modulated by DEHP are predominantly PPARalpha targets. However, the induction of prototypic cytochrome P450 genes strongly supports the activation of additional NR pathways, including Constitutive Androstane Receptor (CAR). Integration of transcriptomic and metabonomic profiles revealed a correlation between the impacts of DEHP on genes and metabolites related to heme synthesis and to the Rev-erbalpha pathway that senses endogenous heme level. We further confirmed the combined impact of DEHP on the hepatic expression of Alas1, a critical enzyme in heme synthesis and on the expression of Rev-erbalpha target genes involved in the cellular clock and in energy metabolism. This work shows that DEHP interferes with hepatic CAR and Rev-erbalpha pathways which are both involved in the control of metabolism. The identification of these new hepatic pathways targeted by DEHP could contribute to metabolic and endocrine disruption associated with phthalate exposure. Gene expression profiles performed on microdissected testis territories displayed a differential responsiveness to DEHP. Altogether, this suggests that impacts of DEHP on adult organs, including testis, could be documented and deserve further investigations.

Variance in male reproductive success and sexual size dimorphism in pinnipeds: testing an assumption of sexual selection theory

The theory of evolution by sexual selection for sexual size dimorphism (SSD) postulates that SSD primarily reflects the adaptation of males and females to their different reproductive roles. For example, competition among males for access to females increases male body size because larger males are better able to maintain dominant status than smaller males. Larger dominant males sire most offspring while smaller subordinate males are unsuccessful, leading to skew in reproductive success. Therefore, species with male-biased SSD are predicted to have greater variance in male reproductive success than those in which both sexes are similar in size. We tested this prediction among the Pinnipedia, a mammalian group with a great variation in SSD. From a literature review, we identified genetic estimates of male reproductive success for 10 pinniped taxa (eight unique species and two subspecies of a ninth species) that range from seals with similarly sized males and females to species in which males are more than four times as large as females. We found no support for a positive relationship between variance in reproductive success and SSD among pinnipeds after excluding the elephant seals Mirounga leonina and Mirounga angustirostris, which we discuss as distinctive cases. Several explanations for these results are presented, including the revival of one of Darwin's original ideas. Darwin proposed that natural selection may explain SSD based on differences in energetic requirements between sexes and the potential for sexual niche segregation. Males may develop larger bodies to exploit resources that remain unavailable to females due to the energetic constraints imposed on female mammals by gestation and lactation. The importance of this alternative explanation remains to be tested.

Weak polygyny in California sea lions and the potential for alternative mating tactics

Female aggregation and male territoriality are considered to be hallmarks of polygynous mating systems. The development of genetic parentage assignment has called into question the accuracy of behavioral traits in predicting true mating systems. In this study we use 14 microsatellite markers to explore the mating system of one of the most behaviorally polygynous species, the California sea lion (Zalophus californianus). We sampled a total of 158 female-pup pairs and 99 territorial males across two breeding rookeries (San Jorge and Los Islotes) in the Gulf of California, Mexico. Fathers could be identified for 30% of pups sampled at San Jorge across three breeding seasons and 15% of sampled pups at Los Islotes across two breeding seasons. Analysis of paternal relatedness between the pups for which no fathers were identified (sampled over four breeding seasons at San Jorge and two at Los Islotes) revealed that few pups were likely to share a father. Thirty-one percent of the sampled males on San Jorge and 15% of the sampled males on Los Islotes were assigned at least one paternity. With one exception, no male was identified as the father of more than two pups. Furthermore, at Los Islotes rookery there were significantly fewer pups assigned paternity than expected given the pool of sampled males (p<0.0001). Overall, we found considerably lower variation in male reproductive success than expected in a species that exhibits behavior associated with strongly polygynous mating. Low variation in male reproductive success may result from heightened mobility among receptive females in the Gulf of California, which reduces the ability of males to monopolize groups of females. Our results raise important questions regarding the adaptive role of territoriality and the potential for alternative mating tactics in this species.

Resource defense polygyny shifts to female defense polygyny over the course of the reproductive season of a Neotropical harvestman

Although studies classify the polygynous mating system of a given species into female defense polygyny (FDP) or resource defense polygyny (RDP), the boundary between these two categories is often slight. Males of some species may even shift between these two types of polygyny in response to temporal variation in social and environmental conditions. Here, we examine the mating system of the Neotropical harvestman Acutisoma proximum and, in order to assess if mate acquisition in males corresponds to FDP or RDP, we tested four contrasting predictions derived from the mating system theory. At the beginning of the reproductive season, males fight with other males for the possession of territories on the vegetation where females will later oviposit, as expected in RDP. Females present a marked preference for specific host plant species, and males establish their territories in areas where these host plants are specially abundant, which is also expected in RDP. Later in the reproductive season, males reduce their patrolling activity and focus on defending individual females that are ovipositing inside their territories, as what occurs in FDP. This is the first described case of an arachnid that exhibits a shift in mating system over the reproductive season, revealing that we should be cautious when defining the mating system of a species based on few observations concentrated in a brief period.

PERFORATING POTENTIAL OF LOLIGINID SPERMATOPHORES

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The periaqueductal gray and its potential role in maternal behavior inhibition in response to predatory threats

Animals faced with conflicting cues, such as predatory threat and a given rewarding stimulus, must make rapid decisions to engage in defensive versus other appetitive behaviors. The brain mechanisms mediating such responses are poorly understood. However, the periaqueductal gray (PAG) seems particularly suitable for accomplishing this task. The PAG is thought to have, at least, two distinct general roles on the organization of motivated responses, i.e., one on the execution of defensive and reproductive behaviors, and the other on the motivational drive underlying adaptive responses. We have presently examined how the PAG would be involved in mediating the behavioral choice between mutually incompatible behaviors, such as reproduction or defense, when dams are exposed to pups and cat odor. First, we established the behavioral protocol and observed that lactating rats, simultaneously exposed to pups and cat odor, inhibited maternal behavior and expressed clear defensive responses. We have further revealed that cat odor exposure up-regulated Fos expression in the dorsal PAG, and that NMDA cytotoxic lesions therein were able to restore maternal responses, and, at the same time, block defensive responsiveness to cat odor. Potential paths mediating the dorsal PAG influences on the inhibition of appetitive (i.e., retrieving behavior) and consummatory (i.e., nursing) maternal responses are discussed. Overall, we were able to confirm the dual role of the PAG, where, in the present case, the dorsal PAG, apart from organizing defensive responses, also appears to account for the behavioral inhibition of non-defensive responses. (C) 2010 Elsevier B.V. All rights reserved.

Reproductive indices in natural nests of giant Amazon river turtles Podocnemis expansa (Schweigger, 1812) (Testudines, Podocnemididae) in the Environmental Protection Area Meanders of the Araguaia river

Realizou-se a contagem dos ovos não eclodidos, dos filhotes vivos e mortos de Podocnemis expansa oriundos de 327 ninhos naturais, localizados nas praias da Área de Proteção Ambiental (APA) - Meandros do Rio Araguaia, onde se determinou a porcentagem de eclosão dos ovos (94,63%); não eclosão (5,37%); sobrevivência (94,24%) e mortalidade dos filhotes (5,76%), e a média de filhotes mortos durante os 15 dias no berçário (0,97%). A média do total de filhotes por ninho foi determinada pela soma do número de filhotes vivos e mortos divididos pelo total de ninhos, enquanto que a média do total de ovos por ninho foi determinada pela soma do número de filhotes vivos, mortos e ovos não eclodidos divididos pelo total de ninhos. Com isso, obtiveram-se os valores médios do número de filhotes vivos (88,98 ± 23,94); mortos (0,37 ± 0,93); ovos não eclodidos (5,07 ± 9,57), e total de ovos (94,42 ± 21,30). A eficiência reprodutiva da população selvagem de P. expansa pode ser afetada por muitos fatores ambientais, como temperatura, umidade e precipitação. Além disso, fatores influenciados pelo homem, como a presença de produtos químicos na água e a possibilidade de doenças infecciosas, também têm impacto significativo. Os dados dos índices reprodutivos obtidos neste estudo são indispensáveis para futuras investigações de anomalias de incubação.

Short- and long-term reproductive effects of prenatal and lactational growth restriction caused by maternal diabetes in male rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fertility-associated antigen on Nelore bull sperm and reproductive outcomes following first-service fixed-time AT of Nelore cows and heifers

The objective was to determine whether the presence of fertility-associated antigen (FAA) on sperm collected from Nelore (Bos indicus) bulls can be used to assess potential fertility of sperm for use at first-service fixed-time AI (TAI). Six Nelore bulls were selected based on FAA status (FAA-negative: N = 3; FAA-positive: N = 3) and the ability to produce neat semen with >= 70% morphologically normal sperm and 60% estimated progressive motility before cryopmservation. In Experiment 1, suckled multiparous Nelore cows (N = 835) were evaluated for body condition score (BCS) and received an intravaginal progesterone device (CIDR) and 2.0 mg of estradiol benzoate (Day 0). on Day 9 the CIDR was removed, 12.5 mg of PGF(2 alpha) and 0.5 mg of estradiol cypionate were administered, and calves were removed for 48 h. All cows received TAI on Day II (48 h after CIDR removal). Pregnancy per TAI (P/TAI) was not different between FAA-positive and FAA-negative bulls (41.5% vs. 39.3%, respectively). There was an effect of AI technician on P/TAI (36.0% vs. 43.9%; P < 0.05) and BCS tended to affect P/TAI (P = 0.09), as cows with BCS >= 2.75 were 1.4 times more likely to become pregnant compared with cows with BCS < 2.75. In Experiment 2, nulliparous Nelore heifers (N = 617) were evaluated for BCS and received a CIDR and estradiol benzoate (2.0 mg) on Day 0. on Day 7, all heifers received PGF(2 alpha) (12.5 mg). on Day 9, CIDR inserts were removed and all heifers received estradiol cypionate (0.6 mg) and 200 IU eCG. All heifers received TAI on Day 11 (48 h after CIDR removal). Pregnancy/TAI was different (P = 0.04) between FAA-positive and FAA-negative bulls (33.7% vs. 40.7%, respectively). Presence of FAA on sperm was unsuccessful in assessing the potential fertility of sperm for use in TAI. (C) 2012 Elsevier B.V. All rights reserved.

5alpha-reductase 2 inhibition impairs brain defeminization of male rats: Reproductive aspects

The present study was carried out to determine whether 5alpha-reductase 2 (5alpha-R2) metabolic pathway plays a key role in brain sexual differentiation. The inhibition of 5alpha-R2 by finasteride (20 mg/kg/day) from gestational day 19 to postnatal day 5 has long-term effects on sexual behavior and reproductive physiology detected only in adult life. Sexual maturation assessed by timing of preputial separation was unchanged. Finasteride-treated males were able to mate with untreated females which became pregnant but exhibited increased rate of pre-implantation loss. The subfertility observed was probably due to abnormally shaped sperm, since the sperm number was not altered. While plasma testosterone was enhanced, LH levels were not changed. The copulatory potential was not affected and all finasteride-treated rats presented male sexual behavior. Despite this, 53% of them showed homosexual behavior when pretreated with estradiol, suggesting an incomplete brain defeminization. These results indicate that 5alpha-R2 acts in brain sexual differentiation of male rats. Moreover, we suggest that 5alpha-R2 not only produces essential metabolites that act together with estradiol in brain sexual differentiation but also protects the brain from the damaging effects of estradiol excess. (c) 2005 Elsevier B.V. All rights reserved.

Sibutramine Effects on the Reproductive Performance of Pregnant Overweight and Non-Overweight rats

It is well established that sibutramine produces weight loss and is used frequently in women of childbearing age. However, the potential adverse consequences attributed to sibutramine use by women who may become pregnant is not known. It was thus of interest to determine the effects of sibutramine on the reproductive performance of pregnant rats. Overweight as well as non-overweight female Wistar rats were treated with sibutramine (6 mg/kg) orally, daily for 15 d and then mated with normal male rats. Pregnancy was confirmed and treatment continued with sibutramine until d 14 of pregnancy. on d 20 of pregnancy all rats were anesthetized for determination of various maternal and fetal parameters. There was a significant maternal weight reduction at the end of pregnancy in the non-overweight drug-treated group compared to the control (non-overweight, no drug). Sibutramine alone and overweight condition alone produced a significant increase in postimplantation loss and placental index. In the overweight with or without sibutramine groups a significant decrease in fetal weight was noted. Data suggest that sibutramine alone or the condition of excess weight in the absence of drugs produced impaired reproductive performance. However, treatment of overweight rats with sibutramine did not further exacerbate fetal loss compared to sibutramine alone or the effects noted with excess weight alone.

Functional and Morphological Reproductive Aspects in Male Rats Exposed to Di-n-Butyl Phthalate (DBP) in Utero and During Lactation

The potential adverse reproductive effects, with emphasis on the epididymis, of in utero and lactational exposure to 100 mg/kg/d di-n-butyl phthalate (DBP) in adult male rat offspring were investigated. The fetal testis histopathology was also determined. The selected endpoints included reproductive organ weights, sperm motility and morphology, sperm epididymal transit time, sperm quantity in the testis and epididymis, hormonal status, fetal testis and epididymal histopathology and stereology, and androgen receptor (AR), aquaporin 9 (AQP9), and Ki-67 immunoreactivities. Pregnant females were divided into two groups: control (C) and treated (T). The treated females received DBP (100 mg/kg/d, by gavage) from gestation day (GD) 12 to postnatal day (PND) 21, while control dams received the vehicle. Some pregnant dams were killed by decapitation on GD20, and testes from male fetuses were collected for histopathogy. Male rats from other dams were killed at PND 90. Fetal testes from treated group showed Leydig-cell clusters, presence of multinucleated germinative cells, and increase of the interstitial component. Testosterone levels and reproductive organ weights were similar between the treated and control adult groups. DBP treatment did not markedly affect relative proportions of epithelial, stromal, or luminal compartments in the epididymis; sperm counts in the testis and epididymis; sperm transit time; or sperm morphology and motility in adult rats. The AR and AQP9 immunoreactivities and proliferation index were similar for the two groups. These results showed that fetal testes were affected by DBP as evidenced by testicular histopathologic alterations, but reproductive parameters and epididymal structure/function were not significantly altered in the adult animals exposed to 100 mg/kg DBP in utero and during lactation.

Reproductive behavior of the swimming crab Arenaeus cribrarius (Lamarck, 1818) (Crustacea, Brachyura, Portunidae) in captivity

In this study, the reproductive behavior exhibited by Arenaeus cribrarius in captivity was described, and the duration of each behavioral stage was measured. Swimming crabs were trawled in Ubatuba, northern littoral of São Paulo State, Brazil, and maintained in aquaria. Water conditions and food items were provided according to this species' natural requirements in the wild. In the presence of premolt females, intermolt males exhibited a courtship display that became intensified when the potential mate was visually perceived. After mate selection, the male carried the female under itself (precopulatory position) for 29.8 +/- 5.1 d until the female molted. Afterwards, the male manipulated the recently molted female, and inverted her position under itself as to penetrate her with his first pair of pleopods (copulation), a process that took 17.1 +/- 4.6 h. After copulation the male continued to carry his soft-shelled mate for 29.7 +/- 5.8 d (postcopulatory position). The time elapsed between copulation and spawning was 57.8 +/- 3.8 d and the time interval between successive spawns 33.8 +/- 7.1 d. Total embryonic development took 13.5 +/- 2.1 d in temperature conditions of 25.0 +/- 2.0 degrees C. During the last 4.7 +/- 1.4 d embryos' eyes were already visible. The reproductive behavior pattern in A. cribrarius is very similar to those previously described in other portunids.