Different variations of tissue B-group vitamin concentrations in short- and long-term starved rats

Abstract

Prolonged starvation changes energy metabolism; therefore, the metabolic response to starvation is divided into three phases according to changes in glucose, lipid and protein utilisation. B-group vitamins are involved in energy metabolism via metabolism of carbohydrates, fatty acids and amino acids. To determine how changes in energy metabolism alter B-group vitamin concentrations during starvation, we measured the concentration of eight kinds of B-group vitamins daily in rat blood, urine and in nine tissues including cerebrum, heart, lung, stomach, kidney, liver, spleen, testis and skeletal muscle during 8 d of starvation. Vitamin B 1 , vitamin B 6 , pantothenic acid, folate and biotin concentrations in the blood reduced after 6 or 8 d of starvation, and other vitamins did not change. Urinary excretion was decreased during starvation for all B-group vitamins except pantothenic acid and biotin. Less variation in B-group vitamin concentrations was found in the cerebrum and spleen. Concentrations of vitamin B 1 , vitamin B 6 , nicotinamide and pantothenic acid increased in the liver. The skeletal muscle and stomach showed reduced concentrations of five vitamins including vitamin B 1 , vitamin B 2 , vitamin B 6 , pantothenic acid and folate. Concentrations of two or three vitamins decreased in the kidney, testis and heart, and these changes showed different patterns in each tissue and for each vitamin. The concentration of pantothenic acid rapidly decreased in the heart, stomach, kidney and testis, whereas concentrations of nicotinamide were stable in all tissues except the liver. Different variations in B-group vitamin concentrations in the tissues of starved rats were found. The present findings will lead to a suitable supplementation of vitamins for the prevention of the re-feeding syndrome.Key words: Starvation: Fasting: Energy metabolism Starvation produces a series of metabolic changes that lead to a reduction in body weight, alterations in body composition and metabolic gene expression (1,2) . In mammals and birds, three distinct levels of energy depletion have been established (3 -10) . The first phase (phase 1) is a rapid period of adaptation marked by an increase in mobilisation of fat stores and a lowering in protein utilisation. During the second phase (phase 2), which is a long period of thrift, most of the energy expenditure is derived from fats, and then fat stores are progressively exhausted, while body proteins are efficiently spared. The third phase (phase 3) is characterised by an increase in protein utilisation. In humans, the negative energy balance resulting from starvation can arise due to disease, eating or psychological disorders, or hunger strikes. Starvation and consequent re-feeding syndrome can lead to electrolyte disorders, especially hypophosphataemia, along with neurological, pulmonary, cardiac, neuromuscular and haematological complications (11) . To avoid the re-feeding syndrome, an additional load of vitamins has been suggested to correct the vitamin deficiencies (11) . ...

Tissue vitamin concentrations are maintained constant by changing the urinary excretion rate of vitamins in rats’ restricted food intake

“…Shibata et al 7) reported that mild food restriction reduced tryptophan-nicotinamide conversion, which helps to explain why death secondary to pellagra is pandemic during the "hungry season" which is defined as off-season of food production. In contrast, Shibata et al 1,2,6) reported that severe food restriction increased tryptophan-nicotinamide conversion because the availability of free-type tryptophan increases with body protein breakdown. Therefore, we proposed that a greater amount of preformed niacin should be ingested during mild food restriction.…”

“…1) We also investigated the effects of long-term (eight-day) starvation on the urinary excretion of B-group vitamins in rats and found that the amounts of all B-group vitamins in urine were decreased by longterm starvation but that the B-group vitamin concentrations in the liver remained almost unchanged. 2) Food restriction, namely energy restriction, is generally characterized by delayed growth and leads to changes in nutrient metabolism. Some reports have revealed the use of preferred phenomena for health maintenance by calorie restriction, such as longevity [3][4][5] and prevention of oocyte aging.…”

Pantothenic Acid Biosynthesis in the Parasite Toxoplasma gondii: a Target for Chemotherapy

“…Tissue levels of pantothenate in mammals are very low (rats, 109 Ϯ 7 nmol/g; human colon, 5.9 Ϯ 0.4 nmol/g) (48,49). Inhibitors of E. coli and M. tuberculosis pantothenate synthetase have been designed, and M. tuberculosis auxotrophic mutants with mutations in pantothenate biosynthetic enzymes are attenuated in animals (50).…”

Excess Vitamin Intake before Starvation does not Affect Body Mass, Organ Mass, or Blood Variables but Affects Urinary Excretion of Riboflavin in Starving Rats

“…Our group reported that urinary excretion levels of water-soluble vitamins reflect recent 1-week intakes of these vitamins 1–4. In addition, we reported that fasting and starvation alters urinary excretion levels of water-soluble vitamins in humans and rats 5,6. The most striking phenomena were the sharp decrease in urinary excretion of vitamin B 1 in humans and rats,5,6 increased urinary excretion of vitamin B 2 in humans,5 and decreased urinary excretion of vitamin B 2 in rats 5,6.…”

“…In addition, we reported that fasting and starvation alters urinary excretion levels of water-soluble vitamins in humans and rats 5,6. The most striking phenomena were the sharp decrease in urinary excretion of vitamin B 1 in humans and rats,5,6 increased urinary excretion of vitamin B 2 in humans,5 and decreased urinary excretion of vitamin B 2 in rats 5,6. These findings showed that urinary excretion levels of water-soluble vitamins do not always reflect intake or nutritional status during fasting and starvation, particularly in terms of vitamins B 1 and B 2 .…”