Dietary threonine restriction specifically reduces intestinal mucin synthesis in rats.

We determined whether the steady-state levels of intestinal mucins are more sensitive than total proteins to dietary threonine intake. For 14 d, male Sprague-Dawley rats (158 +/- 1 g, n = 32) were fed isonitrogenous diets (12.5% protein) containing 30% (group 30), 60% (group 60), 100% (control group), or 150% (group 150) of the theoretical threonine requirement for growth.

The chronic colitis developed by HLA-B27 transgenic rats is associated with altered in vivo mucin synthesis.

HLA-B27 transgenic rats spontaneously developing a chronic inflammation mainly involving the colon are recognized as a powerful animal model for IBD. We investigated the mucin production in 6-month-old HLA-B27 rats by measuring in vivo fractional synthesis rate (FSR) and expression of mucins. In the inflamed colon of HLA-B27 rats, the mucin FSR was stimulated by 75% compared to F-344 controls, while MUC2,3 mRNA expression was unchanged.

Metabolic effects of caffeine in humans: lipid oxidation or futile cycling?

Background: Caffeine ingestion stimulates both lipolysis and energy expenditure.

Objectives: Our objectives were to determine whether the lipolytic effect of caffeine is associated with increased lipid oxidation or futile cycling between triacylglycerol and free fatty acids (FFAs) and whether the effects of caffeine are mediated via the sympathetic nervous system.

Design: Respiratory exchange and [1-(13)C]palmitate were used to trace lipid oxidation and FFA turnover in 8 healthy, young men for 90 min before and 240 min after ingestion of placebo, caffeine (10 mg/kg), or caffeine during beta-adrenoceptor blockade.

Mucin production and composition is altered in dextran sulfate sodium-induced colitis in rats.

We evaluated the small and large intestinal mucin production in a rat model of human ulcerative colitis by measuring the in vivo fractional synthesis rate (FSR) and the expression of mucins. A chronic colitis was induced by oral administration of 5% dextran sulfate sodium (DSS) for 9 days followed by 2% DSS for 18 days. DSS-treated rats showed increased colonic MUC2,3 mRNA levels compared pair-fed controls.

Short-term dietary conjugated linoleic acid supplementation does not enhance the recovery of immunodepleted dexamethasone-treated rats.

Background: Conjugated linoleic acid (CLA) has been reported to decrease fat deposition, and increase lean body mass. This has been broadly inferred to mean that CLA alters protein turnover. However, data to test the effects of CLA on protein turnover are lacking.