Regulation of ornithine decarboxylase synthesis effect of a nutritional deficiency of vitamin B6

Life Sciences ◽  
1974 ◽  
Vol 14 (5) ◽  
pp. 977-983 ◽  
Author(s):  
John A. Sturman ◽  
Leon T. Kremzner
1984 ◽  
Vol 217 (2) ◽  
pp. 573-580 ◽  
Author(s):  
Y Murakami ◽  
T Kameji ◽  
S Hayashi

When rat liver homogenate or its postmitochondrial supernatant was incubated with L-cysteine, but not D-cysteine, ornithine decarboxylase (ODC) lost more than half of its catalytic activity within 30 min and, at a slower rate, its immunoreactivity. The inactivation correlated with production of H2S during the incubation. These changes did not occur in liver homogenates from vitamin B6-deficient rats. A heat-stable inactivating factor was found in both dialysed cytosol and washed microsomes obtained from the postmitochondrial supernatant incubated with cysteine. The microsomal inactivating factor was solubilized into Tris/HCl buffer, pH 7.4, containing dithiothreitol. Its absorption spectrum in the visible region resembled that of Fe2+ X dithiothreitol in Tris/HCl buffer. On the other hand FeSO4 inactivated partially purified ODC in a similar manner to the present inactivating factor. During the incubation of postmitochondrial supernatant with cysteine, there was a marked increase in the contents of Fe2+ loosely bound to cytosolic and microsomal macromolecules. Furthermore, the content of such reactive iron in the inactivating factor preparations was enough to account for their inactivating activity. These data suggested that H2S produced from cysteine by some vitamin B6-dependent enzyme(s) converted cytosolic and microsomal iron into a reactive loosely bound form that inactivated ODC.


Author(s):  
V.J. Montpetit ◽  
S. Dancea ◽  
L. Tryphonas ◽  
D.F. Clapin

Very large doses of pyridoxine (vitamin B6) are neurotoxic in humans, selectively affecting the peripheral sensory nerves. We have undertaken a study of the morphological and biochemical aspects of pyridoxine neurotoxicity in an animal model system. Early morphological changes in dorsal root ganglia (DRG) associated with pyridoxine megadoses include proliferation of neurofilaments, ribosomes, rough endoplasmic reticulum, and Golgi complexes. We present in this report evidence of the formation of unique aggregates of microtubules and membranes in the proximal processes of DRG which are induced by high levels of pyridoxine.


2018 ◽  
Vol 88 (1-2) ◽  
pp. 80-89 ◽  
Author(s):  
Zahra Shakibay Novin ◽  
Saeed Ghavamzadeh ◽  
Alireza Mehdizadeh

Abstract. Branched chain amino acids (BCAA), with vitamin B6 have been reported to improve fat metabolism and muscle synthesis. We hypothesized that supplementation with BCAA and vitamin B6 would result in more weight loss and improve body composition and blood markers related to cardiovascular diseases. Our aim was to determine whether the mentioned supplementation would affect weight loss, body composition, and cardiovascular risk factors during weight loss intervention. To this end, we performed a placebo-controlled randomized clinical trial in 42 overweight and obese women (BMI = 25–34.9 kg/m2). Taking a four-week moderate deficit calorie diet (–500 kcal/day), participants were randomized to receive BCAA (6 g/day) with vitamin B6 (40 mg/day) or placebo. Body composition variables measured with the use of bioelectrical impedance analysis, homeostatic model assessment, and plasma insulin, Low density lipoprotein, High density lipoprotein, Total Cholesterol, Triglyceride, and fasting blood sugar were measured. The result indicated that, weight loss was not significantly affected by BCAA and vitamin B6 supplementation (–2.43 ± 1.02 kg) or placebo (–1.64 ± 1.48 kg). However, significant time × treatment interactions in waist to hip ratio (P = 0.005), left leg lean (P = 0.004) and right leg lean (P = 0.023) were observed. Overall, supplementation with BCAA and vitamin B6 could preserve legs lean and also attenuated waist to hip ratio.


2007 ◽  
Vol 37 (23) ◽  
pp. 30
Author(s):  
SHERRY BOSCHERT
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document