Clinical observations of metabolic changes occurring in renal transplant recipients receiving ketoconazole

Metabolism of cyclosporine is reduced by ketoconazole binding to the monooxygenase responsible for cyclosporine degradation. This isozyme of cytochrome P450, along with other similar monooxygenases, is involved in the regulation of the synthesis and degradation of important metabolic pathways of cholesterol. Monooxygenases throughout these pathways are inhibited by ketoconazole binding causing a decreased metabolism of calcitriol, bile acids, and steroid hormones, and can thereby potentiate altered lipid metabolism, bone metabolism, and weight status of transplant recipients. A group of renal transplant recipients taking ketoconazole (n=25) was compared with a matched cohort not receiving ketoconazole for metabolic changes during the first six months posttransplantation. Lower LDL cholesterol levels were seen in the ketoconazole group (109 +/- 8 mg/dl) than the no ketoconazole group (140 +/- 8 mg/dl) at one month but this difference was not sustained at six months. More bone loss occurred in the ketoconazole group as demonstrated by significant changes in bone density as well as a greater urinary appearance of bone collagen crosslink, deoxy-pyridinoline (29 +/- 4 nmol dpd/mmol creatinine and 18 +/- 4 at six months for the ketoconazole group versus the no ketoconazole group, respectively, P<0.05). Weight gain changes were different between the ketoconazole group and no ketoconazole group (6.4 +/- 1.4 kg versus 5.0 +/- 1.3 kg) at six months and an increased rate of weight gain over time in the ketoconazole group (0.02 kg/day at one month versus 0.05 kg/day at six months, P<0.007). Effectiveness of ketoconazole inhibition of cyclosporine is valuable, but inhibition of other metabolic pathways should be evaluated as well.

Altered concentrations of gastrin-releasing polypeptide and somatostatin in fundic and duodenal bulb mucosa of patients with duodenal ulcer disease

The concentrations of gastrin-releasing polypeptide, somatostatin (SS), and gastrin in extracts of endoscopically obtained biopsies from the fundus, antrum, and duodenum of patients with uncomplicated bile stones (controls) or duodenal ulcer disease were measured with specific radioimmunoassays. The validity of the tissue sampling was confirmed by characteristic and significant differences between gastrin concentrations at the different biopsy sites. Gastrin-releasing polypeptide levels were at their highest in the fundic and duodenal bulb compared to the antrum in controls (p less than 0.01), whereas no differences in gastrin-releasing polypeptide content of the different parts of the stomach were found in duodenal ulcer patients. Compared to controls gastrin-releasing polypeptide in duodenal ulcer patients was reduced in fundic and duodenal bulb mucosa (p less than 0.01). SS levels were highest (p less than 0.05) in the first part of duodenum in controls. Compared to controls duodenal ulcer patients had lower SS concentrations present in fundic (p less than 0.01) and highest SS concentrations present in duodenal bulb mucosa (p less than 0.01). There was no correlation between acid secretion and mucosal gastrin-releasing polypeptide or SS concentrations in any part of the stomach and duodenum.

Effect of neurotensin in the dumping syndrome

The possibility that the gut peptide, neurotensin, may contribute to the dumping syndrome was investigated in 17 patients with a long history of dumping after a Billroth II gastrectomy for duodenal ulcer. After a test meal plasma levels of neurotensin were higher than in normal subjects, but no correlation to the severity of symptoms was found. In eight of the patients with meal-provoked dumping symptoms, intravenous infusion of neurotensin in relevant doses produced neither symptoms nor changes in blood glucose, blood pressure, or pulse rate. The apparent plasma half-life of neurotensin (t1/2 = 2.3 min) did not differ from that previously found in normal subjects. The results indicate that it is unlikely that neurotensin alone has a pathogenetic role in the dumping syndrome in gastrectomized patients.