Comparison of pre- vs. postmeal administration of miglitol for 3 months in type 2 diabetic patients.

AIM: alpha-Glucosidase inhibitors (alphaGIs) primarily modify postprandial plasma glucose levels and should be taken just before meals. We previously demonstrated that a single administration of miglitol within 30 min after the start of a meal was equally effective as when administered just before a meal. We here compared pre- vs. postmeal administration of miglitol for 3 months in type 2 diabetic patients. METHODS: Thirty-one type 2 diabetic outpatients who had never been treated with insulin injections or alphaGIs were randomized to two groups: patients in group A were asked to take miglitol just before meals, while patients in group B were asked to take miglitol after meals. We measured 1,5-anhydroglucitol (1,5-AG) and HbA(1C) levels in these patients. RESULTS: The administration of miglitol after meals for a 3-month period decreased HbA(1C) and increased 1,5-AG levels to the same extent as when administered just before meals. The incidence of adverse effects seemed to be unrelated to the timing of the miglitol administration. CONCLUSIONS: Our results suggest that if patients have difficulty remembering to take miglitol just before meal, they should be instructed to take the medicine together with other medicine(s) after the meal; this instruction may improve the treatment compliance of diabetic patients.

cDNA cloning and expression of a novel cytochrome p450 (cyp4f12) from human small intestine.

A cDNA encoding a novel human CYP4F enzyme (designated CYP4F12) was cloned by PCR from a human small intestine cDNA library. RT-PCR analysis demonstrated that CYP4F12 is expressed in human small intestine and liver. This cDNA contains an entire coding region of a 524-amino-acid protein that is 81.7, 78.3, and 78.2% identical to CYP4F2, CYP4F3, and CYP4F8, respectively. When expressed in Saccharomyces cerevisiae, the P450 catalyzes leukotriene B(4) omega-hydroxylation and arachidonic acid omega-hydroxylation, typical reactions of CYP4F isoforms. Their activity levels are, however, much lower than those of CYP4F2. Interestingly, CYP4F12 catalyzes the hydroxylation of the antihistamine ebastine with significantly higher catalytic activity relative to CYP4F2 (385 vs 5 pmol/min/nmol P450). These results indicate that CYP4F12 has a different profile of substrate specificity from other CYP4F isoforms, enzymes responsible for metabolizing endogenous autacoids, therefore suggesting that it may play an important role in xenobiotic biotransformation in the human small intestine.