[Investigation of the effects and mechanisms of berberine on a mouse model of polycystic ovary syndrome: based on intestinal flora analysis].

Objective: To examine the impact of berberine on polycystic ovary syndrome (PCOS) in mice, and to investigate the effects of berberine on the intestinal flora and the intestinal flora on PCOS. Methods: A mouse model of PCOS was established by administering dehydroepiandrosterone in combination with high fat diet, and the mouse model was given a berberine treatment. The study consisted of a blank control group (C group), a PCOS model group (M group) and a berberine treatment group (T group). During the experiment, the mice were closely monitored through timed body weight measurements and estrous cycle monitoring; intraperitoneal glucose tolerance test and insulin tolerance test were done. Upon completion of the pharmacological intervention, the wet weights of liver, ovary and fat deposits of mice were assessed and subjected to HE staining to confirm the success of PCOS modeling and the efficacy of berberine. Additionally, fecal samples were analyzed for intestinal flora through 16S rRNA analysis. Results: The PCOS model was established successfully, berberine alleviated the disturbance of estrous cycle in mice, and significantly alleviated fat accumulation and metabolic abnormalities of glucose in mice. The cross-sectional area of fat pad cells in T group was (2 858±146) µm², which was significantly lower than that in M group [(9 518±347) µm²], and the difference was statistically significant (P<0.001). The blood glucose levels in T group were significantly lower than those in M group (P<0.05). The composition and structure of intestinal flora in mice of M group with PCOS (compared with C group) and in mice of T group after berberine intervention (compared with M group) were significantly altered. However, alpha diversity did not change significantly among three groups (P>0.05). Conclusion: Berberine could alleviate PCOS by intervening in the alterations of gut microbiota.

[D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C antagonizes neuromedin C-stimulated amylase release by acini isolated from the rat pancreas.

Two novel neuromedin C analogs [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C and [Leu9-psi-CH2NH-Leu10]neuromedin C, were synthesized by rapid solid phase methods and examined for their abilities to inhibit neuromedin C-stimulated amylase release by isolated rat pancreatic acini. Both analogs significantly inhibited maximally stimulated amylase release by neuromedin C in a dose-dependent manner with maximal inhibition seen at concentrations of 100 and 300 microM of [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C and [Leu9-psi-CH2NH-Leu10]neuromedin C, respectively. The IC50 (concentration required to half-maximally inhibit neuromedin C-stimulated amylase release) was 1.5 microM for [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C compared to a 13.4 microM IC50 for [Leu9-psi-CH2NH-Leu10]neuromedin C. The [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C analog produced a parallel rightward shift in the neuromedin C dose-response curve and Schild plots of the inhibition data gave a slope of 0.969 +/- 0.121 and a pA2 (apparent affinity for the acinar cell receptor in terms of neuromedin C receptor-stimulated amylase release) of 100 nM. While [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C significantly inhibited both neuromedin B- and gastrin releasing peptide-stimulated amylase release, the analog did not inhibit amylase release in response to either cholecystokinin octapeptide, vasoactive intestinal peptide, substance P, carbamylcholine, the Ca2+ ionophore A23187, forskolin, or 8-bromo-cyclic AMP. The results demonstrate that [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C is a potent, specific, and competitive antagonist for neuromedin C and peptides of the gastrin releasing peptide family and may serve as a useful molecule for exploring the physiological role of these peptides.

Bovine pancreatic polypeptide as an antagonist of muscarinic cholinergic receptors.

In dispersed acini from rat pancreas, it was found that bovine pancreatic polypeptide (BPP) and its C-fragment hexapeptide amide (PP-6), at concentrations of 0.1 and 30 microM, respectively, could significantly inhibit amylase secretion stimulated by carbachol (P less than 0.01 or 0.05, respectively), and this inhibition by BPP was dose dependent. 45Ca outflux induced by carbachol was also inhibited by BPP or PP-6, but they had no effect on cholecystokinin octapeptide- (CCK-8) or A23187-stimulated 45Ca outflux. BPP was also capable of displacing the specific binding of [3H]quinuclidinyl benzilate to its receptors, and it possessed a higher affinity (ki 35 nM) than carbachol (Ki 1.8 microM) in binding with M-receptors. It is concluded from this study that BPP acts as an antagonist of muscarinic cholinergic receptors in rat pancreatic acini. In addition, BPP inhibited the potentiation of amylase secretion caused by the combination of carbachol plus secretin or vasoactive intestinal peptide. This may be a possible explanation of the inhibitory effect of BPP on secretin-induced pancreatic enzyme secretion shown in vivo, since pancreatic enzyme secretion stimulated by secretin under experimental conditions may be the result of potentiation of enzyme release produced by the peptide in combination with a cholinergic stimulant.