Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.1.1.32 (phosphoenolpyruvate carboxykinase)
 4,204 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Metabolic balance studies were carried out to determine the interrelationships of thyroid hormone-induced lipogenesis, lipolysis, and energy balance in the free-living rat. Intraperitoneal doses of 15 micrograms triiodothyronine (T3)/100 g body wt per d caused an increase in caloric intake from 26.5 +/- 1.7 (mean +/- SEM) kcal/100 g per d to 38.1 +/- 1.5 kcal/100 g per d. Food intake, however, rose only after 4-6 d of treatment and was maximal by the 8th day. In contrast, total body basal oxygen consumption rose by 24 h and reached a maximum by 4 d. Since total urinary nitrogen excretion and hepatic phosphoenolpyruvate carboxykinase mRNA did not rise, gluconeogenesis from protein sources did not supply the needed substrate for the early increase in calorigenesis. Total body fat stores fell approximately 50% by the 6th day of treatment and could account for the entire increase in caloric expenditure during the initial period of T3 treatment. Total body lipogenesis increased within 1 d and reached a plateau 4-5 d after the start of T3 treatment. 15-19% of the increased caloric intake was channeled through lipogenesis, assuming glucose to be the sole substrate for lipogenesis. The metabolic cost of the increased lipogenesis, however, accounted for only 3-4% of the T3-induced increase in calorigenesis. These results suggest that fatty acids derived from adipose tissue are the primary source of substrate for thyroid hormone-induced calorigenesis and that the early increase in lipogenesis serves simply to maintain fat stores. Since the mRNAs coding for lipogenic enzymes rise many hours before oxygen consumption and lipolysis, these results suggest that T3 acts at least in part by an early coordinate induction of the genes responsible for these processes.
 ...
PMID:Functional relationship of thyroid hormone-induced lipogenesis, lipolysis, and thermogenesis in the rat. 198 90

Elevated liver fat content occurs in high-yielding dairy cows during the transition from pregnancy to lactation after fat mobilization and may affect hepatic glucose metabolism, but the degree of liver fat storage is highly variable. Therefore, we studied metabolic and endocrine changes and hepatic glucose metabolism in cows that markedly differ in liver fat content. Multiparous cows from the same herd with high (HFL; n = 10) and low (LFL; n = 10) liver fat contents (mean of d 1, 10, and 21 after calving for each cow, respectively) were studied from 60 d before expected calving to 56 d in milk. Cows were fed ad libitum and all cows received the same diets. Liver samples were taken on d 1, 10, and 21 after calving; mean fat content (+/-SEM) in liver of HFL cows was 174 +/- 9.6 mg/g, whereas mean liver fat content in LFL cows was 77 +/- 3.3 mg/g. Blood samples were taken 20 and 7 d before expected calving and 0, 7, 14, 28, and 56 d after calving to measure plasma concentrations of nonesterified fatty acids, beta-hydroxybutyrate, glucose, insulin, glucagon, insulin-like growth factor-I, and leptin. In liver, glycogen content as well as mRNA levels of phosphoenolpyruvate carboxykinase, pyruvate carboxylase, glucose-6-phosphatase, and glucose transporter were measured by quantitative real-time PCR. Back fat thickness decreased and dry matter intake increased with onset of lactation, and back fat thickness was higher but dry matter intake was lower in HFL than in LFL. Energy-corrected milk yield did not differ between groups, but milk fat content was higher and lactose content was lower in HFL than LFL at the beginning of lactation. Energy balance was more negative in HFL than in LFL. Plasma nonesterified fatty acids and beta-hydroxybutyrate concentrations increased and plasma glucose concentration tended to decrease more in HFL than LFL with onset of lactation. Glucagon to insulin ratios increased more in HFL than LFL with onset of lactation. Hepatic glycogen content was higher in LFL than HFL, whereas mRNA levels of glucose-6-phosphatase and pyruvate carboxylase were higher in HFL than in LFL, and cytosolic phosphoenolpyruvate carboxykinase mRNA level increased similarly after parturition in both groups. In conclusion, an elevated liver fat content was related to greater fat mobilization and reduced feed intake and was associated with effects on hepatic glucose metabolism. As environment and feeding management were the same, individual cow factors were responsible for differences in energy metabolism during the transition period.
 ...
PMID:Performance and metabolic and endocrine changes with emphasis on glucose metabolism in high-yielding dairy cows with high and low fat content in liver after calving. 1930 36