Influence of Lactobacillus brevis 15 and Lactobacillus plantarum 13 on blood glucose and body weight in rats after high-fructose diet.

In recent years, many authors have investigated the possible antidiabetic effect of lactic acid bacteria. Lactobacillus species constitute a major part of the lactic acid bacteria group and have been found to exhibit beneficial effects on the development of diabetes and its complications. In the current study, we investigated the effects of newly characterised Bulgarian Lactobacillus strains, Lactobacillus brevis 15 and Lactobacillus plantarum 13, on blood glucose levels and body weight of rats fed a fructose-enriched diet. An experiment was conducted over a period of 8 weeks with 24 2-month-old Wistar rats randomly assigned to receive a standard diet (Con, control group), fructose-enriched diet (Fr group), standard diet with probiotics given twice a week (Pro group), and fructose-enriched diet with probiotics given twice a week (Pro+Fr group). At the end of the experimental period, a statistically significant increase in body weight was observed in all experimental groups (P<0.0001). The highest rise was seen in the fructose group (Fr, 169±19 g), followed by the Pro+Fr group (153±15 g), Pro group (149±13 g), and Con group (141±5 g). Moreover, the final blood glucose levels had risen significantly in the groups receiving fructose either without (Fr; P<0.0001) or with lactobacilli (Pro+Fr; P=0.002), while the rise was insignificant in the group of rats given probiotic supplementation only (Pro, P=0.071) and inexistent in the Con group (P=0.999). The highest elevation of blood glucose levels was observed in the Fr group (3.18 mmol/l), followed by the Pro+Fr group (2.00 mmol/l) whereas the Pro group showed the lowest levels (0.60 mmol/l). The results of our study suggest that the newly characterised Bulgarian Lactobacillus strains, L. brevis 15 and L. plantarum 13, could be considered as possible probiotics and might be able to prevent some metabolic disturbances.

Participation of extracellular Ca(2+) or ghrelin in peptide-mediated contraction of strips from rat urinary bladder.

Many neuropeptides, like angiotensins and vasopressin, are involved in the regulation of urinary bladder contractile activity. They activate the inositol-triphosphate signal pathway and increase intracellular calcium concentration. To determine the effect of ghrelin and extracellular calcium on the amplitude and force of angiotensin and vasopressin-mediated contractions of detrusor, we used strips from urinary bladder of Wistar rats. The obtained preparations were stimulated with Angiotensin II (Ang II) and arginine-vasopressin (AVP), independently and in combination with CaCl(2) or ghrelin. The simultaneous application of peptide and CaCl(2) increased the amplitude and the integral force (AUC) of muscle contraction for both neuropeptides. If ghrelin was applied to the preparation 30min prior to application of Ang II, it prevented the development of typical Ang II-mediated contraction. Ghrelin did not affect the amplitude of AVP-mediated contraction, but significantly lowered its integral force. Our experimental data indicate that the increase of calcium in the extracellular fluid possesses a synergistic effect on the neuropeptide-mediated contraction. The effects of ghrelin on Ang II- and AVP-mediated contractions allow us to express the assumption that the urinary bladder cells probably have ghrelin receptors which do not activate phospholipase C signal pathway.

[Plasma renin activity in tachistin-stimulated hypercalcemia and under the effect of chlorazine]. / Plazmena reninova aktivnost pri stimulirana chrez takhistin khiperkaltsiemiia i pri prilozhenie na khlorazin.

The aim of the present study was to elucidate the correlation between the Renin secretion and increased Plasma Calcium concentration and the role of Calmodulin in this process. Plasma Renin activity was determined radioimmunologically in 31 white rats, that were grouped as follows: group I - 7 controls loaded for 6 days perorally with 0.5 ml/200 g b.w. glycerin and injected i.m. for 6 days with 0.1 ml/200 g b.w. with 0.9% NaCl; group II - 8 rats, treated for 6 days with Tachistin 0.0025 mg/200 g b.w., dissolved in glycerin 0.5 ml/200 g b.w.; group III - 5 rats, treated with Tachistin 0.005 mg/200 g b.w. in the same manner; group IV - 5 rats injected i.m. with Chlorazin 0.5 mg/200 g b.w. for 6 days; group V - 6 rats, loaded with double dose Tachistin and with Chlorazin 0.5 mg/200 g b.w. for 6 days. Blood samples were taken intracardially on the seventh day from the beginning of the experiment and were analyzed with kits of Sorin-Biomedica-Italy. Our results suggest that the hypercalcemia induced by Tachistin caused a dose-dependent increase of PRA and Ca-Calmodulin complex is the dominant second messenger of Renin secretion.