What men really think about... family holidays
MedWorm Sponsored Message: Find out how you can get your message across here by sponsoring this MedWorm news feed.
Cobalamin deficiency results in an abnormal increase in l-methylmalonyl-co-enzyme-a mutase expression in rat liver and cos-7 cells.
| Related Articles |
Cobalamin deficiency results in an abnormal increase in l-methylmalonyl-co-enzyme-A mutase expression in rat liver and COS-7 cells.
Br J Nutr. 2008 Aug 19;:1-7
Authors: Nakao M, Hironaka S, Harada N, Adachi T, Bito T, Yabuta Y, Watanabe F, Miura T, Yamaji R, Inui H, Nakano Y
The aim of the present study was to examine the effects of cobalamin (Cbl) on the activity and expression of l-methylmalonyl-CoA mutase (MCM) in rat liver and cultured COS-7 cells. The MCM holoenzyme activity was less than 5 % of the total (holoenzyme+apoenzyme) activity in the liver although rats were fed a diet containing sufficient Cbl. When weanling rats were maintained on a Cbl-deficient diet, the holo-MCM activity became almost undetectable at the age of 10 weeks. In contrast, a marked increase in the total-MCM activity occurred under the Cbl-deficient conditions, and at the age of 20 weeks it was about 3-fold higher in the deficient rats than in the controls (108 (sd 14.5) v. 35 (sd 8.5) nmol/mg protein per min (n 5); P < 0.05). Western blot analysis confirmed that the MCM protein level increased significantly in the Cbl-deficient rats. However, the MCM mRNA level, determined by real-time PCR, was rather decreased. When COS-7 cells were cultured in a medium in which 10 % fetal bovine serum was the sole source of Cbl, holo-MCM activity was barely detected. The supplementation of Cbl resulted in a large increase in the holo-MCM activity in the cells, but the activity did not exceed 30 % of the total-MCM activity even in the presence of Cbl at 10 mumol/l. In contrast, the total-MCM activity was significantly decreased by the Cbl supplementation, indicating that Cbl deficiency results in an increase in the MCM protein level in COS-7 cells as well as in rat liver.
PMID: 18710602 [PubMed - as supplied by publisher]
(Source: The British Journal of Nutrition)Absorption, metabolism and excretion of flavanones from single portions of orange fruit and juice and effects of anthropometric variables and contraceptive pill use on flavanone excretion.
| Related Articles |
Absorption, metabolism and excretion of flavanones from single portions of orange fruit and juice and effects of anthropometric variables and contraceptive pill use on flavanone excretion.
Br J Nutr. 2008 Aug 19;:1-12
Authors: Brett GM, Hollands W, Needs PW, Teucher B, R Dainty J, Davis BD, Brodbelt JS, Kroon PA
Oranges are rich sources of flavonoids that are bioactive and may protect against age-related diseases. The absorption of orange flavanones may be affected by factors such as processing and subject anthropometric variables, and the bioactivity of the absorbed phytochemicals depends on how they are metabolised during absorption. In a randomised cross-over study, twenty subjects consumed a single portion of orange fruit (150 g) or juice (300 g) that contained the flavanones narirutin and hesperidin, and an additional 109 subjects across a broad age range (18-80 years) consumed the juice. Flavanone metabolites were measured in regularly collected samples of plasma and urine. After consumption of fruit or juice, flavanone conjugates, but not the aglycones, were detected in plasma and urine. The flavanone conjugates were shown to include the 7- and 4'-O-monoglucuronides of naringenin, the 7- and 3'-O-monoglucuronides of hesperetin, two hesperetin diglucuronides and a hesperetin sulfo-glucuronide, but no aglycones or rutinosides. Analysis of the plasma pharmacokinetic and urinary excretion data on a dose-adjusted basis indicated no difference in absorption or excretion of either flavanone between the fruit and juice matrices. In the extended urinary excretion dataset the individual variation was very large (range 0-59 % urinary yield). There was a small but significant (P < 0.05) decrease in the excretion of hesperetin (but not naringenin) with increasing age (P < 0.05), but the effects of sex, BMI and contraceptive pill use were shown not to be associated with the variation in flavanone excretion.
PMID: 18710603 [PubMed - as supplied by publisher]
(Source: The British Journal of Nutrition)