Effect of estrogens on apoptosis in the pituitary of viscachas (Lagostomus maximus maximus)

Estrogens, acting through their receptors (ERα and ERβ), regulate cell turnover in the pituitary gland, influencing cell proliferation and apoptosis across various species. However, their role in pituitary processes in seasonally reproducing animals remains poorly understood. This study aims to investigate the influence of estrogens, through the expression of their specific receptors, on the apoptosis of PD cells in relation to sexual maturity, the reproductive cycle, and pregnancy in a seasonal reproductive rodent (Lagostomus maximus maximus). ERα and caspase-3-cleaved (CASP3c) immunoreactive (-ir) cells were identified through immunohistochemistry. Apoptotic cells were detected using the TUNEL technique, with quantitative analysis facilitated by image analysis software, alongside measurement of serum estradiol levels using radioimmunoassay The immunostaining pattern for ERα included nuclear (ERαn) and cytoplasmic (ERαc) staining. In male viscachas, ERα expression significantly increases from immature to adult animals, correlating with the rise in serum estradiol levels and a decrease in the percentage of apoptotic cells. During the gonadal regression period in adult males, a decrease in the number of ER-ir cells and serum levels of estradiol corresponds with an increase in the number of apoptotic cells. In females, serum levels of estradiol peaked during mid-pregnancy, coinciding with a significant decrease in the number of apoptotic cells in the PD. Simultaneously, the percentage of ERαn-ir cells reaches its maximum value during late pregnancy, indicating the need to maintain the protective action of this gonadal hormone throughout the extensive pregnancy in these rodents. Regional ERα receptor expression and apoptotic cells appear to be associated with distinct PD cell populations and their hormonal responses. Finally, elevated estradiol levels coincide with diminished apoptotic cells in the male reproductive cycle and during pregnancy, suggesting an antiapoptotic role of estradiol in this species.

17-α-Ethinylestradiol modulates endocrine and behavioral responses to stress in zebrafish

The synthetic estrogen, 17-α-ethinylestradiol (EE2), present in contraceptive pills, is an endocrine-disrupting chemical (EDC) that can be found in the aquatic environment. We examined the impacts of EE2 on zebrafish behavioral and physiological responses through the novel tank test (NTT), which measures anxiety-like behavior; the mirror-induced aggression (MIA) test, which measures aggressiveness; and the social preference test (SPT), which measures social cohesion. The steroid hormone levels were also measured. Here, we show that exposure to EE2 impairs stress responses by regulating the levels of specific hormones and eliciting an anxiolytic response, increasing aggression, and reducing social preference in zebrafish. In nature, these changes in behavior compromise reproduction and anti-predator behaviors, which, in turn, affects species survival. The maintenance of an intact behavioral repertoire in zebrafish is essential for their survival. Thus, our results point to the danger of environmental contamination with EE2 as it may alter the dynamics of the prey-predator relationship.

Postprandial inflammatory responses after oral glucose, lipid and protein challenges: Influence of obesity, sex and polycystic ovary syndrome

BACKGROUND & AIMS

Most evidence linking the polycystic ovary syndrome (PCOS) with chronic low-grade inflammation has been obtained in the fasting state. We have studied the postprandial inflammatory response to oral glucose, lipid and protein challenges and the possible influences of obesity, sex and PCOS on these responses.

METHODS

On alternate days, we submitted 17 women with PCOS (9 non-obese, 8 obese), 17 control women (9 non-obese, 8 obese) and 19 control men (10 non-obese, 9 obese) to isocaloric (300 Kcal) oral macronutrient loads. We assayed serum for TNF-α, IL-6, IL-18, IL-10, pentraxin-3 and galectin-3 concentrations and leukocytes for expression of TNF, IL6, IL10 and their receptors TNFRSF1B, IL6R and IL10RA.

RESULTS

Circulating IL-6 levels decreased after glucose and protein ingestion but slightly increased after oral lipid intake. Leukocyte IL6 expression did not change after the ingestion of any macronutrient yet IL6R expression increased during all macronutrient challenges, the largest increase being observed after glucose ingestion. Serum TNF-α similarly decreased during either macronutrient load, whereas TNF expression increased after macronutrient ingestion, the highest increase observed after oral glucose. TNFRSF1B expression also increased after glucose intake but not after lipid or protein ingestion. No global effect of obesity or group on postprandial circulating IL-6, TNF-α, or IL6, IL6R, TNF and TNFRSF1B expression was found. Circulating IL-18 concentrations decreased during all oral challenges, whereas in case of galectin-3 and pentraxin-3 only the protein load caused a reduction in its concentrations. Of the genes studied here, IL10 showed the largest increase in expression throughout all the postprandial curves, particularly after glucose. Obesity blunted the increase in IL10 expression. IL10RA expression decreased after glucose ingestion but remained unchanged during lipid and protein loads.

CONCLUSIONS

Glucose ingestion, as opposed to lipid and protein intake, results into the largest increase in leukocyte gene expression of inflammatory mediators. The expression of the anti-inflammatory cytokine IL10 was the largest observed here, suggesting a compensatory mechanisms against postprandial inflammation that may be blunted in obesity. However, these responses did not translate into the circulating concentrations of these inflammatory mediators during the immediate postprandial phase.

Effects of atrazine on vitellogenesis, steroid levels and lipid peroxidation, in female red swamp crayfish Procambarus clarkii

Atrazine, a widely use herbicide, has been classified as a potential endocrine disruptor, especially for freshwater species. In this study, we tested the hypothesis that atrazine can affect reproduction in crayfish through dysregulation of vitellogenin expression and hormone synthesis. Adult female crayfish (Procambarus clarkii) were exposed during one month to atrazine at concentrations of either 1 or 5 mg/L. At the end of the exposure, ovaries, hepatopancreas, and hemolymph samples were harvested for analysis of vitellogenin expression and steroid hormone levels. Ovarian tissue was also sampled for both biochemical and histological analyses. Our results show that atrazine-exposed crayfish had a lower expression of vitellogenin in the ovary and hepatopancreas, as well as smaller oocytes, and reduced vitellogenin content in the ovary. Despite these effects, circulating levels of estradiol increased in females exposed to 5 mg/L of atrazine, showing that the inhibiting effect of atrazine on vitellogenin production was not related to a lower secretion of sexual steroids. Instead, some early stimulating effects of estradiol on vitellogenesis could have occurred, particularly in the hepatopancreas. On the other hand, atrazine caused a higher metabolic effort, in terms of lactate production, presumably triggered to provide the energy needed to face the unspecific stress produced by the herbicide. Lipid peroxidation was not affected by atrazine, but glutathione levels were significantly increased.

Reproductive and parental care physiology of Cichlasoma dimerus males

The South American cichlid fish Cichlasoma dimerus presents a high breeding frequency and biparental care of the eggs and larvae. The male parental care period was divided in four different phases according to the developmental degree of the offspring: pre-spawning activity (MP, day 0), guarding eggs (ME, one day after fertilization (1 DAF)), guarding hatched larvae (MHL, 3 DAF), and guarding swimming larvae (MSL, 8 DAF). The aim of this study was to characterize male reproductive physiology by measuring steroid hormone plasma levels and analyzing testes cellular composition. Males exhibiting pre-spawning activity showed 8.4 times higher 11-ketotestosterone and 5.63 times higher testosterone levels than MHL. No differences were observed in estradiol and cortisol levels among the different phases. The cellular composition of the testes varied during the reproductive and parental care periods. Testes of MP were composed of 50% of spermatozoa, whereas spermatogonia type B and spermatocytes were predominant in the subsequent parental phases. A morphometric analysis of Leydig cells nuclear area revealed that MP and ME's Leydig cells averaged 1.27 times larger than that those of MHL and MSL and was positively correlated with circulating 11-KT and T levels. Hence, C. dimerus males showed important changes in its hormonal profiles and testicular cellular composition throughout the reproductive and parental care period.