Problem: Gestational obesity and insulin resistance pose a significant threat to the future health of our population. Mothers and children of these metabolically maladaptive pregnancies experience extensive morbidity and mortality. This study characterized postprandial insulin sensitivity in female Sprague Dawley rats at 5-days and 15-days gestation. Based on these findings, a model of gestational obesity was developed using 35% sucrose supplementation (SS). The efficacy of a preventative and a therapeutic intervention at modulating sucrose-induced gestational insulin resistance in Sprague Dawley rats was elucidated. Methods: Insulin sensitivity in the post-prandial state includes insulin-dependent and Hepatic Insulin Sensitizing Substance (HISS)-dependent components, and can be characterized with the Rapid Insulin Sensitivity Test (RIST). HISS is a putative hepatic factor released in the fed-state that selectively increases glucose uptake in skeletal muscle, kidney and heart. In the first phase of this study, the effects of insulin were assessed in pregnant animals (5 and 15-days gestation) and their virgin controls. Groups of 15-day gestation and virgin animals had SS for 8-weeks (with a 2-week recovery), 10-weeks or 22-weeks. Half of all of the 10-week SS animals were treated with either SAMEC (given chronically, containing S-adenosyl-methionine, vitamin C and vitamin E) or BENAC (given once the night before the acute study, containing bethanechol chloride and n-acetyl-l-cysteine). Body weight, weight gained over the gestational period, fat pad mass, post-prandial glycemia, plasma insulin and triglyceride concentrations were measured in all groups. Results: 5-days gestation was associated with preserved direct insulin action and increased HISS-dependent insulin action. 15-days gestation was associated with a mixed insulin resistance: both direct and HISS-dependent insulin action were reduced. SS in these pregnant and virgin rats eliminated HISS-dependent insulin action, associated with hyperinsulinemia, hypertriglyceridemia and obesity. In the SS group given 8-weeks of sucrose (then a 2-week recovery), virgins spontaneously partially recovered HISSdependent insulin action. At 15-days gestation, recovery was complete with reductions in plasma insulin and triglyceride concentrations, and normalization of body weight and fat pad mass. 10-week SS resulted in complete absence of HISS-dependent insulin action, and produced a model of gestational obesity. Prolonged (22-week) SS did not result in hyperglycemia or elevation of plasma insulin concentration above 10-week SS. SAMEC in 10-week SS 15-day pregnant and virgin rats prevented the loss of HISS-dependent insulin action, and normalized plasma insulin and triglyceride concentrations. BENAC given to 10-week SS virgin and 15-day pregnant rats normalized overall insulin responses secondary to restoration of HISS-dependent insulin action. This was accompanied by a reduction (for virgins) and normalization (at 15-days gestation) of plasma insulin and triglyceride concentrations. In 15-day pregnant controls (no sucrose), BENAC increased the HISS-dependent insulin action significantly above baseline and reduced plasma triglycerides and insulin below control levels. Conclusions: These results suggest an explanation for the insulin resistance occurring in pregnancy, whereby HISS may facilitate metabolic adaptation. HISS may represent a pathophysiological missing link in the insulin resistant disorders of pregnancy. These findings substantiate a series of unexplored treatments (including BENAC and SAMEC) for the epidemic of gestational obesity and diabetes in mothers-to-be and the deleterious metabolic programming occurring in the next generation.

The existing research works, dealing with pre-copulatory behaviour in Pyrrhocoris apterus (L.), show that this behaviour follows a simple pattern of mating. The aim of this work is to extend knowledge regarding this type of behaviour. Results were obtained by processing the video footage to monitor the behaviour of individuals of the Central European population (the Czech Republic) as occurred in the respective copulatory zone. Changes were observed in the occurrence and mating activity of each sex depending on climatic conditions and time. Furthermore, the course of individual phases of the mating behaviour, based on mutual interactions and under the influence of external factors, was also observed. These results were supplemented by adding data gained from laboratory experiments, taking place at a temperature of 22 ± 4 řC and involving a long- day type photoperiodic reaction. Based on the results gained, it had been revealed that the climatic conditions significantly influenced the course of behaviour. Individuals of both sexes are physically active during the photo-phase when the intensity of this activity changes in the course of the circadian rhythm. Females display a higher sensitivity to any variation in climate. Males who are influenced by the presence of receptive females show greater locomotive...

The aim of the present thesis is to give a comparision on sex determination of phenotypically undifferentiated birds species focused on the Long-eared Owl (Asio otus). Compared to other species of owls is relatively a few researches on the Long-eared Owl and researches on sex differences have not led to the quantified results yet. Attention is focused on characteristics and mechanisms of birds coloration. This work includes the methods and results of colour perception and interpretation in sexual dimorphism. It focuses primarily on the differences in color of certain parts of the bird, such as the alula, secondary remiges and lower part of the wing. For those pieces is further evaluating color differences in sex and proposes solutions that could help in further researches on sex determination of the Long-eared Owl.