Effects of exercise, detraining, starvation, and refeeding on lipogenic capacity of Osborne-Mendel rat

1988 ◽  
Vol 254 (4) ◽  
pp. R648-R654
Author(s):  
P. Lowney ◽  
V. M. Lee ◽  
R. J. Hansen ◽  
J. S. Stern
Keyword(s):  
Enzyme Activity ◽  
Plasma Glucose ◽  
Liver Lipid ◽  
Liver Triglyceride ◽  
Phosphogluconate Dehydrogenase ◽  
Hepatic Glucose ◽  
Liver Triglycerides ◽  
Lipid Stores ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Final Speed

Both starvation and refeeding and exercise and detraining are procedures that result in lowered lipid stores followed by their refilling. Rats subjected to these procedures were evaluated for their ability to produce hepatic biosynthetic reducing equivalents. Five-week-old male Osborne-Mendel rats were exercised on a motorized treadmill for 6 wk (final speed 27 m/min, 60 min/day, 6 day/wk) or kept sedentary. Exercised and sedentary rats were starved for 48 h or fed ad libitum. After treatments, some rats in each group were killed. Remaining exercised animals were detrained or detrained and refed. Remaining sedentary rats were refed. Activities of hepatic glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and malic enzyme were evaluated. Plasma glucose, triglyceride, insulin, liver triglyceride, and body composition were determined. Results indicate that changes in lipids stores associated with starvation and refeeding and exercise and detraining are not associated with similar changes in enzyme activity. Starvation resulted in lowered plasma glucose, triglyceride, and insulin. Starvation and all exercise treatments resulted in lowered carcass fat. Exercised rats who were starved for 48 h and then detrained and refed for 72 h had the greatest liver weights and percent liver triglycerides. This was not associated with similar changes in enzyme activity. Increased liver lipid and decreased carcass fat may indicate a redistribution of lipid stores in these animals.

THE INFLUENCE OF ADRENALECTOMY UPON THE ACTIVITY OF THE HEXOSEMONOPHOSPHATE SHUNT IN THE LIVERS AND MAMMARY GLANDS OF LACTATING RATS

1960 ◽  
Vol 38 (1) ◽  
pp. 1265-1273 ◽  
Author(s):  
J. S. Willmer
Keyword(s):  
Enzyme Activity ◽  
Considerable Increase ◽  
Mammary Glands ◽  
Mammary Tissue ◽  
Hepatic Tissue ◽  
Phosphogluconate Dehydrogenase ◽  
Growth Changes ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Adrenalectomized Rats ◽  
Hepatic Level

The development of the hexosemonophosphate shunt in mammary tissue and liver of lactating rats has been studied. A sixfold increase in mammary glucose-6-phosphate dehydrogenase levels between parturition and weaning was accompanied by a considerable increase in 6-phosphogluconate dehydrogenase activity. The hepatic level of the former enzyme was also elevated 11-fold during this period. Adrenalectomy at parturition, or on the 3rd, 6th, 9th, or 14th days of lactation, depressed the activity of this pathway in mammary gland, a lowered level being observed in all cases after operation. A slight increase in enzyme activity was found in hepatic tissue in the immediate postoperative period; this was succeeded by a decrease.These results are discussed in relation to the growth changes observed in groups of unoperated and adrenalectomized rats.

The induction by exogenous hormones of enzymes metabolising glucose 6-phosphate in the mammary gland of the pseudopregnant rabbit

1969 ◽  
Vol 36 (1) ◽  
pp. 47-52 ◽  
Author(s):  
R. J. Heitzman
Keyword(s):  
Enzyme Activity ◽  
Mammary Gland ◽  
Enzyme Activities ◽  
Synergistic Action ◽  
Phosphate Metabolism ◽  
Exogenous Hormones ◽  
Phosphogluconate Dehydrogenase ◽  
Intraductal Injection ◽  
Glucose 6 Phosphate Dehydrogenase

SummaryA study was made of the effects of the hormones, prolactin and cortisol acetate, on the activities in the mammary gland of the pseudopregnant rabbit of the enzymes concerned with lactose biosynthesis and glucose 6-phosphate metabolism, namely: UDP-glucose pyrophosphorylase, UDP-glucose-4'-epimerase, phosphofructokinase, phosphoglucomutase, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Significant increases in enzyme activities were observed in rabbits examined 3 or 4 days after receiving a mammary intraductal injection of prolactin. The activities were not significantly increased at examination 2 days after injection of prolactin. Rabbits receiving cortisol acetate each day for 3 days also showed no significant increases in mammary enzyme activity. However, when prolactin and cortisol acetate were given simultaneously over a period of 3 days, increased enzyme activities were found suggesting synergistic action of the hormones.

THE INFLUENCE OF ADRENALECTOMY UPON THE ACTIVITY OF THE HEXOSEMONOPHOSPHATE SHUNT IN THE LIVERS AND MAMMARY GLANDS OF LACTATING RATS

1960 ◽  
Vol 38 (11) ◽  
pp. 1265-1273 ◽  
Author(s):  
J. S. Willmer
Keyword(s):  
Enzyme Activity ◽  
Considerable Increase ◽  
Mammary Glands ◽  
Mammary Tissue ◽  
Hepatic Tissue ◽  
Phosphogluconate Dehydrogenase ◽  
Growth Changes ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Adrenalectomized Rats ◽  
Hepatic Level

The development of the hexosemonophosphate shunt in mammary tissue and liver of lactating rats has been studied. A sixfold increase in mammary glucose-6-phosphate dehydrogenase levels between parturition and weaning was accompanied by a considerable increase in 6-phosphogluconate dehydrogenase activity. The hepatic level of the former enzyme was also elevated 11-fold during this period. Adrenalectomy at parturition, or on the 3rd, 6th, 9th, or 14th days of lactation, depressed the activity of this pathway in mammary gland, a lowered level being observed in all cases after operation. A slight increase in enzyme activity was found in hepatic tissue in the immediate postoperative period; this was succeeded by a decrease.These results are discussed in relation to the growth changes observed in groups of unoperated and adrenalectomized rats.

scholarly journals Kinetic Behaviour of Glucose 6-Phosphate Dehydrogenase and 6-Phosphogluconate Dehydrogenase in Different Tissues of Rainbow Trout (Oncorhynchus mykiss) Exposed to Non-Lethal Concentrations of Cadmium

2009 ◽  
Vol 78 (1) ◽  
pp. 179-185 ◽  
Author(s):  
Olcay Hisar ◽  
Adem Yavuz Sönmez ◽  
Şükrü Beydemir ◽  
Şükriye Aras Hisar ◽  
Telat Yanik ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Dose Response ◽  
Enzyme Activities ◽  
Response Pattern ◽  
Base Line ◽  
Phosphogluconate Dehydrogenase ◽  
Liver And Kidney ◽  
Glucose 6 Phosphate Dehydrogenase

The effects of cadmium (Cd) on the enzymatic activities of glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) were investigated in the gill, liver and kidney tissues of rainbow trout (Oncorhynchus mykiss). Three test groups of fish were subjected to increasing concentrations (1, 3 and 5 mg/l) of cadmium (Cd) in vivo, respectively. The G6PD and 6PGD activities in the gill, liver, and kidney tissues of each group of fish were measured on days 1, 3, 5 and 7. G6PD and 6PGD enzyme activities, measured in gill, liver and kidney homogenates, were stimulated by various concentrations (1, 3, and 5 mg/l) of cadmium. Although the dose-response pattern of G6PD enzyme activities in liver and kidney tissue was very similar, that in gill was different from both other tissues. The enzyme activity of G6PD enzyme was significantly stimulated after three days (Day 3) in liver and kidney tissues at a dose of 1 mg/l Cd (p < 0.05), whereas it was stimulated on the first day of experiment (Day 1) in gill, liver and kidney tissues at doses of 3 and 5 mg/l Cd (p < 0.05). However, the activity of 6PGD was stimulated after three days (Day 3) in the liver at a dose of 1 mg/l Cd (p < 0.05) and on the first day in gill, liver and kidney tissues at doses of 3 and 5 mg/l Cd (p < 0.05). The stimulation effect of the 5 mg/l dose of Cd on G6PD and 6PGD enzyme activities was significantly diminished after seven days (Day 7) in all tissues (p < 0.05). In contrast to the dose-response pattern at the dose of 5 mg/l Cd, G6PD and 6PGD enzyme activities were stimulated significantly (p < 0.05) in liver and kidney tissues at the doses of 3 and 1 mg/l Cd. The stimulation effect of cadmium on the three tissues studied was also calculated; for both of the enzymes (G6PD and 6PGD), the enzyme activity levels were stimulated by approximately 60% and 38% in gills, 68% and 44% in liver, and 67% and 41% in kidneys, respectively, over the base-line enzyme activity of the control groups during the sevenday experimental period. These findings indicate that tissue G6PD and 6PGD enzymes function to protect against cadmium toxicity.

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