Effect of chenodeoxycholic acid on the alterations of biliary lipid secretion induced by ethynylestradiol in the rat.

The role of chenodeoxycholic acid (CDCA) in modifying the biliary secretory alterations induced by ethynylestradiol (EE) was evaluated in male Sprague-Dawley rats. Bile flow and bile acid output were both decreased in rats given EE either alone or with CDCA (EE + CDCA) whereas cholesterol output showed a significant decrease only in animals given the combined treatment. The output of phospholipids remained unchanged in all groups. As a result the lithogenic index was significantly decreased in EE + CDCA-treated rats. In urine, the total bile acid excretion was significantly increased in EE + CDCA-treated animals. The data indicate that in the rat, biliary secretory failure induced by EE is not modified by CDCA, but that CDCA may prevent the increase of biliary cholesterol saturation caused by EE.     

Effect of chenodeoxycholic acid on the alterations of biliary lipid secretion induced by ethynylestradiol in the rat

The role of chenodeoxycholic acid (CDCA) in modifying the biliary secretory alterations induced by ethynylestradiol (EE) was evaluated in male Sprague-Dawley rats. Bile flow and bile acid output were both decreased in rats given EE either alone or with CDCA (EE + CDCA) whereas cholesterol output showed a significant decrease only in animals given the combined treatment. The output of phospholipids remained unchanged in all groups. As a result the lithogenic index was significantly decreased in EE + CDCA-treated rats. In urine, the total bile acid excretion was significantly increased in EE + CDCA-treated animals. The data indicate that in the rat, biliary secretory failure induced by EE is not modified by CDCA, but that CDCA may prevent the increase of biliary cholesterol saturation caused by EE.     

Effect of prooxidants on insulin secretion by the isolated rat pancreas

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 116, No 8, pp. 165–167, August, 1993     

Effects of insulin on hepatic lipid synthesis in alloxan diabetic rats.

In vitro hepatic synthesis of lipids starting from 1-(14)C-acetate was studied in rats made diabetic by subcutaneous alloxan administration (175 mg/kg b.w.). A second group of diabetic rats was treated with lente insulin. In the alloxan-treated rats, a decrese was observed in hepatic incorporation of 1-(14)C-acetate into phospholipids, triglycerides and esterified cholesterol; there was an increased incorporation into nonesterified fatty acids (NEFA) and free cholesterol. Insulin administration restored lipid synthesis values to normal. On histologic examination, an intranuclear glycogenesis was observed in the hepatocytes of the alloxan-treated rats, along with severe hepatic necrosis; the latter however, only in rats sacrified on the 3rd day. Hepatic steatosis with small, medium and large droplets was present in the insulin-treated rats; signs of cellular degeneration were less evident.     

Comparative effects of cimetidine on biliary lipid secretion in fasted and fed rats.

The effect of cimetidine on biliary lipid secretion has been investigated in fasted and fed rats with biliary drainage for 4 h after a single intraperitoneal administration at a dose of 120 mg/kg body weight. Bile flow, bile acids, cholesterol and phospholipids in bile have been determined. In intact rats similarly treated, serum bile acids, cholesterol and phospholipids have been determined. Biochemical and morphological studies have been conducted on the liver tissue in both experiments. Bile flow and bile acid secretion were not affected by cimetidine in fasted rats, but, 15 min after administration of the drug, fed rats showed an increase of the molar percentage of cholic acid together with a decrease of deoxycholic acid, a decreased secretion of cholesterol and an increased secretion of phospholipids. The values of these biliary lipids were in the range observed in fasted animals, so that the drug appeared to ''mimic'' the effect of fasting. These findings could be related to altered vascular properties of the gastro-intestinal wall induced by cimetidine, leading to interference with intestinal postprandial hyperaemia and capillary permeability, so that there appears to be a conversion of bile composition from a digestive to an interdigestive pattern.     

Biliary lipid secretion in the regenerating liver of the rat.

The effect of two-thirds hepatectomy on biliary lipid secretion was studied in fasted rats. Bile acids, cholesterol and phospholipids were determined in the bile of rats with biliary drainage. Bile acid and phospholipid concentrations were not significantly modified during liver regeneration but there was a significant decrease in cholesterol concentrations in bile at 12 h after hepatectomy, with a gradual return to normal values. The molar percentage of cholesterol and the calculated lithogenic index of bile were also significantly decreased by 12 h. The biliary secretion of bile acids and phospholipids, expressed per gram of liver, showed a tendency to increase regeneration, but cholesterol secretion was significantly decreased from 12 to 48 h following liver resection. Some possibilities to explain the uncoupling between cholesterol secretion and bile acid secretion are discussed.     

Effect of barbiturates on selective secretion of rat salivary glands after administration of anions

Secretion of labeled anions and their metabolites in the saliva of adult Wistar rats was studied. The salivary glands are characterized by high selectivity of secretion of materials. After subcutaneous injection of [¹⁴C]acetate, [³²P]orthophosphate, [³⁵S]thiocyanate, and [¹³¹I]iodide, in control animals under physiological conditions¹⁴C is concentrated in the mixed saliva 2.5–6 times more than in the blood, the³²P level in the saliva is 1/5–1/20 of the blood level, and the¹³¹I and³⁵S indices occupy an intermediate position between those of¹⁴C and³²P. Penetration of labeled anions and their metabolites into mixed saliva from the blood was considerably altered in rats receiving barbital sodium (medinal): the relative activity of¹⁴C,³⁵S, and¹³¹I in the saliva compared with the blood was lower in these rats than in the control animals, but the relative activity of³²P in the saliva compared with the blood was higher than in the control rats.Department of Biochemistry, N. A. Semashko Moscow Medical Stomatologic Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR S. V. Anichkov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 6, pp. 693–696, June, 1978.     

Effect of insulin on human chorionic gonadotrophin secretion by placental explants

The effect of physiological concentrations of insulin (5–50µU/ml) was tested on human chorionic gonadotrophin (HCG)secretion by first trimester (7–9 weeks) and term placentalexplants using both static and dynamic culture models. In staticcultures, insulin exerted a significant biphasic inhibitoryeffect (80% at 5 µU/ml and 40% at 50 µU/ml) on HCGsecretion by placental explants. At approximate fasting plasmalevels, 25 µU/ml insulin added to superfused explantsfor 8 min also had a rapid inhibitory effect. A delayed inhibitoryeffect on HCG pulsatility was also observed using 25 µU/mlinsulin, with a 2-fold decrease in HCG pulse amplitude and a4-fold decrease in the area under the curve following overnightpre-incubation (P < 0.01). Insulin had no effect in staticcultures at term. The effect of insulin-like growth factor (IGF-I)and fibroblast growth factor (bFGF) on HCG secretion in staticcultures was not statistically significant. In conclusion, physiologicalconcentrations of insulin inhibit HCG secretion in first trimesterplacenta in vitro. This effect is gestational age dependentand specific since it is not mimicked by IGF-I or bFGF. Thus,insulin may be an important modulator of trophoblastic HCG secretionduring early pregnancy.     

Biliary lipid secretion during the prereplicative phase of rat liver regeneration.

The prereplicative phase-related changes in spontaneous and taurocholate-induced biliary lipid secretion were studied in anaesthetized male Wistar rats (250 g). Rats underwent two-thirds hepatectomy 1, 6 or 12 h before starting to collect bile samples. As compared with non-hepatectomized rats, biliary lipid secretion was increased at 1 h after hepatectomy and then restored to values similar to the control group up to 12 h after hepatectomy. In separate experiments, taurocholate was infused (200 nmol/min/g calculated liver weight) through the jugular vein over 80 min. Both taurocholate-induced bile flow and bile acid output were similar in control and hepatectomized rats, regardless of the time of the prereplicative phase considered. By contrast, taurocholate-induced lecithin and cholesterol outputs were markedly modified. The former was lowered throughout the prereplicative phase, whereas the latter increased at 6 h and decreased at 12 h. In summary, these results indicate that shortly after hepatectomy bile acid-induced biliary lipid secretion is profoundly modified, probably due to changes in the plasma membrane involved in preparing the hepatocyte to enter the cell cycle.     

Comparative effects of cimetidine on biliary lipid secretion in fasted and fed rats

The effect of cimetidine on biliary lipid secretion has been investigated in fasted and fed rats with biliary drainage for 4 h after a single intraperitoneal administration at a dose of 120 mg/kg body weight. Bile flow, bile acids, cholesterol and phospholipids in bile have been determined. In intact rats similarly treated, serum bile acids, cholesterol and phospholipids have been determined. Biochemical and morphological studies have been conducted on the liver tissue in both experiments. Bile flow and bile acid secretion were not affected by cimetidine in fasted rats, but, 15 min after administration of the drug, fed rats showed an increase of the molar percentage of cholic acid together with a decrease of deoxycholic acid, a decreased secretion of cholesterol and an increased secretion of phospholipids. The values of these biliary lipids were in the range observed in fasted animals, so that the drug appeared to 'mimic' the effect of fasting. These findings could be related to altered vascular properties of the gastro-intestinal wall induced by cimetidine, leading to interference with intestinal postprandial hyperaemia and capillary permeability, so that there appears to be a conversion of bile composition from a digestive to an interdigestive pattern.     

局部应用胰岛素对糖尿病大鼠烫伤创面愈合的影响

目的研究局部应用胰岛素对糖尿病大鼠烫伤创面愈合的作用,初步探索相关机制。方法 60只Wistar大鼠经高脂饮食喂养和小剂量脲佐菌素（STZ）多次注射诱导糖尿病,5周后,造成背部皮肤20%TBSA深Ⅱ度烫伤。随机分为胰岛素治疗组和对照组（每组30只大鼠）,分别于创面下浸润注射0.2 U中性胰岛素和等体积0.9%氯化钠溶液。观察创面愈合速度及伤后第1、4和12天两组创面表皮角质形成细胞迁移、炎症细胞浸润以及胶原沉积情况。酶联免疫吸附测定法检测创面活化素A（Activin A）、单核细胞趋化蛋白-1（MCP-1）和血小板衍生因子A（PDGF-A）水平。结果胰岛素治疗组创面愈合时间明显缩短,血糖无明显变化。和对照组相比,胰岛素治疗组伤后第4天创面表皮迁移舌长度明显延长;伤后第12天创面胶原沉积增加;创面巨噬细胞浸润和消退的时间提前,巨噬细胞在创面表达特征与创面MCP-1表达趋势一致。伤后第1、4天胰岛素治疗组创面Activin A的表达分别（142.52±15.26）pg/mL和（271.46±49.73）pg/mL,较对照组创面的（52.36±33.18）pg/mL和（46.08±8.92）pg/mL明显增加（P=0.0057,0.0001）,PDGF-A于伤后第1、4天的表达分别为（52.12±9.00）pg/mL和（74.75±7.00）pg/mL较对照组的（47.35±8.21）pg/mL和（34.07±5.05）pg/mL也有明显增加（P=0.4080,0.0001）。结论局部应用胰岛素促进创面巨噬细胞的浸润和提早消退、促进表皮细胞的迁移和血管生成相关细胞因子表达和胶原组织沉积,从而促进糖尿病大鼠烫伤创面的愈合。