FURTHER STUDIES ON CARBOHYDRATE METABOLISM IN THE VITAMIN-B6-DEPRIVED RAT

1955 ◽  
Vol 33 (1) ◽  
pp. 161-166
Author(s):  
John R. Beaton

Earlier studies in this laboratory demonstrated abnormalities in carbohydrate metabolism in the vitamin-B6-deprived rat. The results of further studies are reported in this communication. Following three weeks of vitamin B6 restriction, rats have significantly elevated levels of inorganic phosphorus and glutathione in blood and liver. These elevations in blood inorganic phosphorus and glutathione levels have been similarly demonstrated after only one week of vitamin B6 deprivation. Contrary to changes in liver glycogen levels, muscle glycogen levels are not altered by vitamin B6 deprivation in the rat. Insulin administration had a slightly more pronounced effect on blood sugar levels in vitamin-B6-deprived than in pair-fed control rats. Alloxan administration elevated blood sugar levels of deprived rats to a slightly greater extent than the levels of controls. In accord with the earlier studies, disturbances of carbohydrate metabolism can be readily demonstrated in vitamin-B6-deprived rats.

1955 ◽  
Vol 33 (2) ◽  
pp. 161-166 ◽  
Author(s):  
John R. Beaton

Earlier studies in this laboratory demonstrated abnormalities in carbohydrate metabolism in the vitamin-B6-deprived rat. The results of further studies are reported in this communication. Following three weeks of vitamin B6 restriction, rats have significantly elevated levels of inorganic phosphorus and glutathione in blood and liver. These elevations in blood inorganic phosphorus and glutathione levels have been similarly demonstrated after only one week of vitamin B6 deprivation. Contrary to changes in liver glycogen levels, muscle glycogen levels are not altered by vitamin B6 deprivation in the rat. Insulin administration had a slightly more pronounced effect on blood sugar levels in vitamin-B6-deprived than in pair-fed control rats. Alloxan administration elevated blood sugar levels of deprived rats to a slightly greater extent than the levels of controls. In accord with the earlier studies, disturbances of carbohydrate metabolism can be readily demonstrated in vitamin-B6-deprived rats.


1957 ◽  
Vol 190 (2) ◽  
pp. 239-242
Author(s):  
B. N. Spirtos ◽  
R. G. Stuelke ◽  
N. S. Halmi

Rats fed 10 gm of a commercial diet for 4–5 weeks and fasted for 24 hours showed less rise in liver glycogen and blood sugar levels in response to the injection of epinephrine than did ad libitum-fed-fasted rats. Gastrocnemius glycogen levels were found to be higher in underfed-fasted animals and fell to the same extent as in ad libitum fed-fasted animals when epinephrine was given. Blood lactate concentrations, however, rose less markedly in the underfed-fasted group. This may have been at least partly responsible for the diminished rise in hepatic glycogen and blood sugar.


1954 ◽  
Vol 32 (6) ◽  
pp. 684-688 ◽  
Author(s):  
J. R. Beaton ◽  
M. E. Goodwin

The results of in vivo and in vitro studies on carbohydrate metabolism in the vitamin-B6-deprived rat are reported. All comparisons were made with pair-fed control animals. Within five days of vitamin B6 restriction, rats have significantly lowered fasting levels of blood sugar and liver glycogen. These abnormalities are more marked after 21 days of deprivation and are accompanied by significantly lowered fasting blood levels of pyruvic acid and lactic acid. The activity of lactic acid dehydrogenase, one enzyme involved in carbohydrate metabolism, was measured in vitro and found to be significantly depressed in the vitamin-B6-deprived rat. The conclusion is drawn that an abnormal metabolism of carbohydrate occurs in rats deprived of vitamin B6. This abnormality is evident early in the deprivation period.


1954 ◽  
Vol 32 (1) ◽  
pp. 684-688
Author(s):  
J. R. Beaton ◽  
M. E. Goodwin

The results of in vivo and in vitro studies on carbohydrate metabolism in the vitamin-B6-deprived rat are reported. All comparisons were made with pair-fed control animals. Within five days of vitamin B6 restriction, rats have significantly lowered fasting levels of blood sugar and liver glycogen. These abnormalities are more marked after 21 days of deprivation and are accompanied by significantly lowered fasting blood levels of pyruvic acid and lactic acid. The activity of lactic acid dehydrogenase, one enzyme involved in carbohydrate metabolism, was measured in vitro and found to be significantly depressed in the vitamin-B6-deprived rat. The conclusion is drawn that an abnormal metabolism of carbohydrate occurs in rats deprived of vitamin B6. This abnormality is evident early in the deprivation period.


1955 ◽  
Vol 33 (1) ◽  
pp. 562-567
Author(s):  
John R. Beaton

Following earlier studies on carbohydrate metabolism in the vitamin-B6-deprived rat, in vitro investigations have been carried out. In all cases, comparisons were made between tissues from vitamin-B6-deprived and pair-fed control animals so that differences in the amount of food consumed would not affect the interpretation of experimental results. No significant difference was found in glucose utilization by muscle nor in liver cytochrome oxidase activity. Liver aldolase activity was significantly decreased and the activity of plasma alkaline phosphatase was significantly increased in the vitamin-B6-deprived rats. In vitamin-B6-deprived female rats, but not male rats, liver catalase activity was significantly increased. These results are discussed in the light of earlier observations indicating disturbances in carbohydrate metabolism in the vitamin-B6-deprived rat.


1956 ◽  
Vol 187 (3) ◽  
pp. 432-436 ◽  
Author(s):  
N. S. Halmi ◽  
B. N. Spirtos

A) Rats fed 10 gm of ground Rockland diet/day for 4–6 weeks and then fasted for 24 hours showed an enhanced insulin sensitivity as compared with ad libitum-fed rats that were fasted for the same length of time. The fasting blood sugar and liver glycogen concentrations were significantly higher in underfed animals. B) Underfed rats were fasted 24 hours, then fed 5 gm/ 100 gm body weight and tested 8 hours later. These rats exhibited a) no greater insulin sensitivity, b) lower blood sugar levels and c) a smaller rise in liver glycogen concentration than similarly treated ad libitum-fed animals. Intestinal absorption of glucose was not diminished in the undernourished rats. C) Cortisone treatment (0.5 mg/100 gm body wt/day for 5 days) abolished the insulin sensitivity of underfed rats without altering the hepatic glycogen concentration. Somatotrophin (0.5 mg Armour standard equivalent/100 gm body wt/day for 5 days) did not improve their insulin tolerance. After functional evisceration, the blood sugar fall (if expressed as percentage of the initial level) was significantly slower in underfed than in ad libitum-fed rats. However, the decline of the blood sugar level appeared to be more markedly enhanced by insulin in the underfed animals.


1975 ◽  
Vol 32 (6) ◽  
pp. 753-760 ◽  
Author(s):  
D. J. McLeay ◽  
D. A. Brown

In the static study (no exercise), liver glycogen stores were unchanged during 12-h exposure to 0.8 of the 96-h LC50; longer exposures caused a progressive decrease to levels one fifth those of controls at 72 h. Plasma glucose levels in fish held in 0.8 LC50 effluent for 3–96 h were elevated; at 96 h, glucose had increased threefold. Mean values for plasma lactate were elevated significantly at 3, 6, 24, 72, and 96 h.In the exercise (swimming one body length per second)–rest study, muscle glycogen levels decreased 53–78% during exercise in water or effluent (0.7 LC50) for 4–12 h, and did not recover during 12-h rest in water. Muscle glycogen for fish exercised for 12 h in effluent and then rested for 4 or 12 h in effluent was lower compared to values for fish exercised in effluent and then rested in water. There was no difference in liver glycogen levels offish exercised in effluent or water for 4–12 h. Values of liver glycogen for fish exercised in effluent for 12 h and then rested for 4, 8, or 12 h in effluent decreased 60–70% compared to fish exercised in water for 12 h and then rested in water and by 55–65% from fish exercised in effluent for 12 h and rested in water for 4–12 h. Plasma glucose levels were elevated one- to fourfold during exercise in water or effluent. Fish resting in water for 4, 8, or 12 h following exercise in water had relatively stable glucose levels; whereas for fish exercised and then rested in effluent the glucose levels increased twofold during resting. Plasma lactate levels were elevated five- to sixfold during exercise in water or effluent for 4–12 h, declining to values 1–2 times those of stock fish within 4-h rest. Plasma lactate levels for fish exercised in effluent and then rested in effluent or water were continually higher than those for fish exercised and rested in water.It was concluded that measurement of carbohydrate metabolites, particularly blood sugar levels, in unexercised fish could prove useful as a rapid method for measuring toxicity of pulpmill effluents and other pollutants.


1925 ◽  
Vol 19 (4) ◽  
pp. 633-637 ◽  
Author(s):  
Philip Eggleton ◽  
Louis Gross
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