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R W Hanson

Publications and source records attributed to R W Hanson.

188 records · Page 11Linked to original sources
PubMed1966

Factors influencing the utilization of ketone bodies by mouse adipose tissue.

Factors influencing the utilization of ketone bodies by mouse adipose tissue in vitro were studied. Epididymal fat pads can oxidize DL-Beta-hydroxybutyrate-3-(14)C and acetoacetate-3-(14)C to (14)CO(2) as well as convert these compounds to fatty acid-(14)C. An increased output of (14)CO(2) from Beta-hydroxybutyrate-3-(14)C was noted in response to glucose plus insulin, succinate, oxaloacetate, L-asparate, and L-malate. Fatty acid synthesis from Beta-hydroxybutyrate was enhanced by glucose plus insulin, L-aspartate, L-malate, oxaloacetate, and citrate. Nicotinamide stimulated the oxidation of Beta-hydroxybutyrate but not of acetoacetate to CO(2), and did not affect fatty acid synthesis from either ketone body. Nicotinamide increased NAD(+) and NADP(+) levels in epididymal fat pads without affecting the concentration of NADH and NADPH. "Superlipogenesis" caused by fasting the mice for 48 hr and re-feeding them for 24 hr sharply enhanced CO(2) output and lipogenesis from Beta-hydroxybutyrate. The activities of glucose-6-phosphate dehydrogenase, 6-phosphogluconic dehydrogenase, NADP-malic dehydrogenase, and citrate cleavage enzyme from mouse adipose tissue were increased during "superlipogenesis." Free fatty acid release by epididymal fat pads in vitro was slightly increased by Beta-hydroxybutyrate. The relationship of ketone body metabolism and lipogenesis in adipose tissue is discussed.

Acetoacetates↗
PubMed1966

Adaptive changes in enzyme activity and metabolic pathways in adipose tissue from meal-fed rats.

A number of metabolic factors and the activity of a number of enzymes were determined in meal-fed (animals fed a single daily 2 hr meal) and nibbling (ad libitum-fed) rats. The dependency of the observed adaptive changes on the ingestion of carbohydrate was studied by feeding diets high in carbohydrate or fat. Glucose-6-phosphate dehydrogenase and NADP-malic dehydrogenase were more active in adipose tissue from high carbohydrate meal-fed rats than in tissue from ad libitum-fed rats. The activity in adipose tissue of isocitric dehydrogenase, 6-phosphogluconate dehydrogenase, and NAD-malic dehydrogenase did not increase significantly in response to meal-feeding the high carbohydrate diet. No increase in lipogenesis or enzyme activity could be demonstrated in adipose tissue from rats meal-fed a high fat diet. Lipase activity of adipose tissue was increased by high carbohydrate meal-feeding and decreased by feeding a high fat diet. The in vitro uptake of palmitate-1-(14)C by adipose tissue was depressed by a high fat diet and enhanced in rats meal-fed a high carbohydrate diet. Diaphragm or slices of liver from high fat-fed rats oxidized palmitate-1-(14)C more rapidly than did tissue from ad libitum-fed animals. Evidence is presented for the quantitative importance of citrate as a source of extramitochondrial acetyl CoA in adipose tissue of meal-eating and ad libitum-fed rats. The relationship of extramitochondrially formed citrate to the NAD-malic dehydrogenase-malic enzyme system in adipose tissue is discussed.

Acetates↗
PubMedDate not supplied

Regulation of phosphoenolpyruvate carboxykinase (GTP) gene transcription.

Transcription of the gene for phosphoenolpyruvate carboxykinase is regulated by several hormones which control the level of glucose synthesis in vertebrate animals. A 490 bp segment located at the 5' end of the structural gene contains the necessary regulatory elements to account for the pattern of transcriptional regulation characteristic of the phosphoenolpyruvate carboxykinase gene. Multiple cis binding sites within the promoter and nuclear binding proteins have been identified and shown to play a role in the regulation of gene transcription. The interaction of these transcription factors with each other and with the phosphoenolpyruvate carboxykinase promoter is central to the regulated expression of this gene. The key role of cAMP and insulin in controlling the level of gene transcription will be discussed and related to the function of transcription factors currently known to regulate the tissue specific expression of the phosphoenolpyruvate carboxykinase gene.

Animals↗
PubMedDate not supplied

Regulation of phosphoenolpyruvate carboxykinase (GTP) synthesis in the kidney.

Phosphoenolpyruvate carboxykinase activity increases in the kidney after glucocorticoid administration and in acidosis. In both cases, a selective stimulation of the synthesis of phosphoenolpyurvate carboxykinase can account for the augmentation of the enzyme level. Using an assay based on the translation of phosphoenolpyruvate carboxykinase mRNA in a heterologous cell-free protein synthesizing system, we show that the glucocorticoids and acidosis, acting by independent mechanisms, cause an increase in the level of functional mRNA coding for the enzyme of sufficient magnitude to explain the increase in the rate of enzyme synthesis.

Acidosis, Renal Tubular↗