Metabolic Lateralization in the Hypothalamus of Male Rats Related to Reproductive and Satiety States.

The hypothalamus is the main regulatory center of many homeostatic processes, such as reproduction, food intake, and sleep-wake behavior. Recent findings show that there is a strongly interdependent side-linked localization of hypothalamic functions between the left and right hemispheres. The goal of the present study was to trace functional asymmetry of the hypothalamus related to the regulation of food intake and reproduction, in male rodents. Subjects were examined through measurements of mitochondrial metabolism ex vivo. Impact of gonadectomy and scheduled feeding was tested on the modulation of hypothalamic metabolic asymmetry. Results show that in male rats, functional lateralization of the hypothalamus can be attributed to the satiety state rather than to reproductive control. Fasting caused left-sided metabolic dominance, while satiety was linked to the right hemisphere; trends and direction in sided dominance gradually followed the changes in satiety state. Our findings revealed satiety state-dependent metabolic differences between the two hypothalamic hemispheres. It is therefore concluded that, at least in male rats, the hypothalamic hemispheres control the satiety state-related functions in an asymmetric manner.

Estrogen- and Satiety State-Dependent Metabolic Lateralization in the Hypothalamus of Female Rats.

Hypothalamus is the highest center and the main crossroad of numerous homeostatic regulatory pathways including reproduction and energy metabolism. Previous reports indicate that some of these functions may be driven by the synchronized but distinct functioning of the left and right hypothalamic sides. However, the nature of interplay between the hemispheres with regard to distinct hypothalamic functions is still unclear. Here we investigated the metabolic asymmetry between the left and right hypothalamic sides of ovariectomized female rats by measuring mitochondrial respiration rates, a parameter that reflects the intensity of cell and tissue metabolism. Ovariectomized (saline injected) and ovariectomized+estrogen injected animals were fed ad libitum or fasted to determine 1) the contribution of estrogen to metabolic asymmetry of hypothalamus; and 2) whether the hypothalamic asymmetry is modulated by the satiety state. Results show that estrogen-priming significantly increased both the proportion of animals with detected hypothalamic lateralization and the degree of metabolic difference between the hypothalamic sides causing a right-sided dominance during state 3 mitochondrial respiration (St3) in ad libitum fed animals. After 24 hours of fasting, lateralization in St3 values was clearly maintained; however, instead of the observed right-sided dominance that was detected in ad libitum fed animals here appeared in form of either right- or left-sidedness. In conclusion, our results revealed estrogen- and satiety state-dependent metabolic differences between the two hypothalamic hemispheres in female rats showing that the hypothalamic hemispheres drive the reproductive and satiety state related functions in an asymmetric manner.

Hypothalamic sidedness in mitochondrial metabolism: new perspectives.

Morphofunctional changes in hypothalamic neurons are highly energy dependent and rely on mitochondrial metabolism. Therefore, mitochondrial adenosine triphosphate production plays a permissive role in hypothalamic regulatory events. Here, we demonstrated that in the female rat hypothalamus, mitochondrial metabolism and tissue oxygenation show an asymmetric lateralization during the estrous cycle. This asymmetry was not detected in males. The observed sidedness suggests that estrous cycle-linked hypothalamic functions in females are based on hemispheric distinction. The novel concept of hypothalamic asymmetry necessitates the revision of hypothalamic neural circuits, synaptic reorganization, and the role of hypothalamic sides in the regulation of integrated homeostatic functions.

Expression of the neonatal Fc receptor (FcRn) in the bovine mammary gland.

In ruminants, protective immunoglobulins are transferred to the newborn via colostrum to mediate maternal immunity. There is a high selectivity in the transport of immunoglobulins from the maternal plasma across the mammary barrier into the colostrum, and only IgG1 is transferred in large amounts. We have recently analysed the expression of the neonatal Fc receptor (FcRn) in sheep mammary gland around parturition. Re-analysing this issue in bovine confirmed our previous data indicating that FcRn is homogeneously localized in the mammary gland acinar cells before parturition, however a remarkable difference was observed in the pattern after calving, where only the apical side of the cells was strongly stained. The presence of the FcRn in the acinar epithelial cells of the mammary gland and the obvious change in distribution before and after parturition indicate that FcRn plays an important role in the IgG transport during colostrum formation in ruminants.

Effect of precultivation conditions on colicin susceptibility in Escherichia coli.

The effect of 20 colicins and cloacin was studied after various precultivations. Nutrient agar supplemented with subinhibitory concentration of EDTA used for precultivation or elevating the growth-temperature of the inoculum from 37 degrees C to 42 degrees C increased the susceptibility of wild-type (smooth) Escherichia coli strains to the inhibitory action of some colicins. There were great differences among the colicins in respect to these effects. In case of rough mutants, their sensitivities did not change or eventually decrease after EDTA or heat pretreatment. The LPS pattern in SDS-PAGE of smooth cells grown in EDTA-containing nutrient medium changed in some degree towards the rough character. In case of precultivation at 42 degrees C this change was less considerable. It is supposed that both factors applied during precultivation have influence on colicin sensitivity by means of the change of receptor activity caused by LPS modification.

Antibiotic resistance and plasmid profiles of Escherichia coli and Klebsiella isolated from in-patients receiving prolonged antibiotic therapy.

Distribution by serogroup, phage type, colicin production, colicin type, sensitivity to antibiotics and plasmid characteristics of 74 Escherichia coli and 11 Klebsiella strains isolated from hospitalized patients receiving prolonged antibiotic therapy indicated that the infections were not associated with the hospital environment. Resistance was tested to 26 antibiotics, some of them being not generally used in therapy; 30 strains were resistant to 4 to 17 antibiotics. There was a significant difference in the antibiotic resistance of strains derived from patients with urinary-tract infections (UTI) and with leukaemia (LP). As compared to the UTI group, among E. coli strains in the LP group the frequency of multiple resistance was significantly higher, the MIC values were higher and R-plasmids were more frequent. Out of 30 multiple resistant E. coli strains 27 were R-plasmid carriers. Three different kinds of plasmid profile were shown in more than one strain (2 out of 10 UTI strains and 3 and 2 out of 10 LP strains). The rest of the isolates differed in plasmid profile from these and from one another; the presence of "epidemic plasmid" was not demonstrated. Plasmid epidemiological examinations may forecast the efficacy of an antibiotic or of a group of antibiotics.