Sperm impairments in adult vesper mice (Calomys laucha) caused by in utero exposure to bisphenol A.

This study aimed to evaluate the effects of in utero administration of bisphenol A (BPA) on semen parameters of vesper mice. Sixty female Calomys laucha were divided into six groups and received by gavage during gestation the following substances: Water (negative control), Olive Oil (vehicle control), Diethylstilbestrol (DES - positive control - 6.5 µg kg(-1) bw) and BPA (40, 80 and 200 µg kg(-1) bw). Male offspring were euthanised at 70 days of age, and sperm parameters were analysed. BPA reduced normal sperm morphology (water = 96.1 ± 0.65; BPA200 = 96.8 ± 2.3%), sperm membrane integrity (water = 88.8 ± 1,65; BPA200 = 70.6 ± 4,15%), sperm motility (water = 87.5 ± 1.71; BPA200 = 51.3 ±9.9%) and in vitro penetration rates (water = 55.0 ± 7.14; BPA200 = 7.47 ±2.96%), but it did not affect body weight, anogenital distance, sperm DNA integrity and acrosome integrity. In conclusion, in utero exposure to BPA caused a reduction in sperm parameters of adult C. laucha. Natural mating studies should be conducted to verify the effects of BPA on fertility of the animals.

Influence of mineral, olive or sunflower oils on male reproductive parameters in vitro--the wild rodent Calomys laucha.

The aim of this study was to evaluate the influence of oils on male reproductive parameters in Calomys laucha. Twenty-four animals were distributed into four groups and given the following substances by gavage: water, mineral oil, olive oil and sunflower oil. After 10 days of gavage, the animals were euthanised and the semen was collected from them for assessing acrosome integrity and carrying out in vitro penetration (IVP) test. Acrosome was significantly reduced (P < 0.05) for the vehicles in relation to control. In vitro penetration was reduced in all vehicles in relation to control, but only sunflower oil had statistically lower levels of reduction (P < 0.05). Oily vehicles are able to influence in vitro reproductive tests negatively, interfering in reproductive toxicological studies.

Importance of cholinesterase kinetic parameters in environmental monitoring using estuarine fish.

The aim of the present study was to determine the kinetic parameters and cholinesterase (ChE) activity in two teleost fish, the white mouth croaker Micropogonias furnieri (Scianidae) and the Madamango sea catfish Cathorops spixii (Ariidae), to verify their suitability as sentinel species of aquatic pollution by anticholinergic compounds. Individuals of each species were captured in one reference and one polluted site in the Southern Brazilian coast. Brain tissue was used as enzyme source. Inhibition kinetic parameters indicated that ChE from C. spixii collected at the reference site showed more affinity (Ka) for eserine that from those collected at the polluted site. The opposite was observed for the carbamylation constants (Kc). Thus, similar inhibition constants (Ki) were observed. M. furnieri brain showed an extremely low sensitivity to in vitro inhibition by eserine, indicating that it is not a suitable biomarker to be employed in environmental monitoring of anticholinergic compounds. Results from the present study also point to the need for considering kinetic analysis when cholinesterase activity is employed as a biomarker.

Sex steroid imbalances in the muricid Stramonita haemastoma from TBT contaminated sites.

Imposex incidence, organotin tissue levels, and sex steroid (free and esterified testosterone and estradiol) levels were assessed in Stramonita haemastoma from Babitonga Bay (Santa Catarina State, Southern Brazil). The imposex levels showed a reduction when compared to a previous evaluation performed in the same area. In spite of that, the detected imposex incidence indicated the occurrence of tributyltin (TBT) inputs that were still able to produce endocrine disruption in local gastropods. In addition, a high level of organotins was observed in tissues of imposexed females. These females also showed a hormonal imbalance, especially in the total testosterone/total estradiol ratio. These findings obtained under realistic field conditions suggest that the steroid pathway could be responsible by the imposex induction after exposure to TBT. In this case, measurements of sex steroid levels can be an additional evidence for monitoring sites and impose affected gastropod populations.

Blood glucose changes in the blue crab Callinectes sapidus Rathbun on transfer from sea water to air.

Intertidal decapods regulate their blood glucose with a significant but transitory (60 min) increase upon exposure to atmospheric air, and this has been considered to be an adaptative response related to the almost complete lack of the Pasteur effect in facultative anaerobes. In these animals we would not observe an increase in substrate availability to cope with the small amount of energy furnished by anaerobic pathways but rather a general metabolic depression. However, this hypothesis has never been tested by conducting similar experiments with infralittoral species. For this reason, groups of five Callinectes sapidus were transferred from sea water to atmospheric air and their blood glucose levels were determined 15, 30, 60, 120 and 240 minutes afterwards. Glucose levels increased gradually from 16.41 +/- 4.45 mg/100 ml to 127.18 +/- 33.40 mg/100ml (mean +/- SEM). The linear relationship between time of exposure and glucose levels suggests that intertidal and infralittoral species present different mechanisms of blood glucose regulation.

Effects of food supplementation on litter size and oestradiol concentration during gestation and oestrous cycle of capybaras (Hydrochaeris hydrochaeris) in captivity.

The present study analysed the response of adult female capybaras (Hydrochaeris hydrochaeris) to different dietary supplementation in relation to litter size per parturition and oestradiol secretion profile during pregnancy and the oestrous cycle. All four experimental groups received 'camerum' grass (Pennisetum purpureum) and water ad libitum and three of the groups were also fed a protein, lipid or protein and lipid supplement. Litter size per parturition did not show any significant difference among treatment groups, but was significantly higher (P < 0.05) than in the control group. There was no significant difference in oestradiol concentrations among treatments and the control group, during each phase of the oestrous cycle or during gestation. The average oestradiol concentrations in dioestrous, oestrous and metoestrous phases were not significantly different from each other, but were significantly lower (P < 0.05) than the average oestradiol concentration in the pro-oestrous phase. In addition, average oestradiol concentrations increased after the second gestation month, but were significantly higher (P < 0.05) only after the fourth gestation month, achieving maximum value by the end of gestation. Dietary supplementation had no significant effect on hormonal concentrations during the oestrous cycle and gestational period. However, an increase in litter size per parturition was observed among female capybaras that received dietary supplementation.

Serum leptin concentration during the terrestrial phase of the Southern elephant seal Mirounga leonina (Carnivora: Phocidae).

This study aimed to verify the serum leptin concentration during the terrestrial phase of the Southern elephant seal (Mirounga leonina) on Elephant Island (South Shetlands, Antarctica). Sera from 25 adult Southern elephant seals were analyzed. Leptin concentration was determined using the 125I radioimmunoassay method. Total protein, triglycerides, and cholesterol concentration were measured by spectrophotometric methods. Seals were grouped by sex and their physiological status (reproducing or molting seals). In reproducing seals, serum concentrations of leptin, total protein, triglycerides, and cholesterol were, respectively, 9.33+/-1.97 ng/ml, 6.87+/-0.09 g/dl, 98.26+/-2.12 mg/dl, and 232.17+/-41.18 mg/dl in males and 5.30+/-1.36 ng/ml, 6.44+/-0.29 g/dl, 109.01+/-3.34 mg/dl, and 219.20+/-26.65 in females (mean+/-1 SD). In molting seals, these values were 2.35+/-1.51 ng/ml, 7.42+/-0.25 mg/dl, 321.10+/-20.01 mg/dl, and 244.66+/-22.24 mg/dl in males and 2.94+/-1.89 ng/ml, 7.88+/-0.46 mg/dl, 197.54 mg/dl, and 224.55+/-16.70 mg/dl in females. In both males and females, there were no significant differences (P>0.05) in total protein and cholesterol concentration between reproducing and molting seals. However, both males and females showed higher leptin concentration (P<0.05) and lower triglyceride concentration (P<0.05) in the reproductive period than in the molt period. In the reproductive period, it was expected that the Southern elephant seal shows an inhibited hunger sensation, mobilizes stored energy, and stimulates the HPG axis. Results from the present study support this hypothesis and suggest that this strategy may be effected by the hormonal stimulation of leptin.

Blood glucose changes in the blue crab Callinectes sapidus Rathbun on transfer from sea water to air

Intertidal decapds regulate their blood glucose with a significant but transitory (60 min) increase upon exposure to atmospheric air, and this has been considered to be an adaptative response related to the almost complete lack of the Pasterur effect in facultative anaerobes. In these animals we would not observe an increase in substrate availability to cope with the small amount of energy furnished by anaerobic pathways but rather a general metabolic depression. However, this hypothesis has never been tested by conducting similar experiments with infralittoral species. For this reason, groups of five Callinectes sapidus were transferred from sea water to atmospheric air and their blood glucose levels were determined 15,30, 60, 120 and 240 minutes afterwards. Glucose levels increased gradually from 16.41 ñ 4.45 mg/100 ml to 127.18 ñ 33.40 mg/100 ml (x ñ SEM). The relationiship between time of exposure and glucose levels suggests that intertidal and infralittoral species presetn different mechanisms of blood glucose regulation