Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.3.1 (citrate synthase)
 4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sixteen prepubertal Friesian heifers were used to examine the effect of bovine growth hormone (GH) and ovariectomy (OVX) at 2.5 mo of age (2 x 2 factorial design) on growth, carcass quality, and fiber types, capillarization, and metabolic potentials of the longissimus muscle, and serum concentrations of estradiol-17beta (E2beta), insulin, GH, IGF-I, and IGF-binding proteins (IGFBP). Treatment with GH (15 mg/d) started at 147 +/- 3 kg BW and lasted for 15 wk. Heifers were fed a mixed roughage-based diet. Growth hormone increased ADG (P < .001), improved gain:feed (P < .007), and had a small but positive influence on lean accretion. Growth hormone reduced fat thickness (P < .009), carcass fat trim (P < .009) and i.m. fat (P < .09). Ovariectomy did not affect performance but increased dressing percentage (P < .03), full rib weight (P < .003), and fat thickness (P < .04). Ovariectomy reduced E2beta (P < .001) and insulin (P < .02), and increased the 32-kDa IGFBP (IGFBP-2) (P < .09). Growth hormone treatment increased GH, IGF-I, the 28-kDa IGFBP, and the 40- to 43-kDa IGFBP (IGFBP-3) (P < .004 or P < .001). Neither GH nor ovariectomy affected the proportion and relative area of the individual muscle fiber types, but GH tended to increase type I fiber area (P < .10). Number of capillaries per fiber increased in OVX GH-treated heifers (GH x OVX interaction, P < .02). Activities of citrate synthetase were higher in GH-treated (P < .05) and OVX (P < .02) heifers, indicating increased oxidative capacity of the longissimus muscle. The effects of GH on performance and carcass fattening were in accordance with the observed hormonal changes. When slaughter occurs before puberty, ovariectomy has no effect on performance, only few effects on carcass quality, and small effects on hormone concentrations.
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PMID:Effects of growth hormone and ovariectomy on performance, serum hormones, insulin-like growth factor-binding proteins, and muscle fiber properties of prepubertal Friesian heifers. 865 31

The purpose of this study was to investigate variations in hepatic regulation of metabolism during the dry period, after parturition, and in early lactation in dairy cows. For this evaluation, cows were divided into 2 groups based on the plasma concentration of beta-hydroxybutyric acid (BHBA) in wk 4 postpartum (PP; group HB, BHBA >0.75 mmol/L; group LB, BHBA <0.75 mmol/L, respectively). Liver biopsies were obtained from 28 cows at drying off (mean 59 +/- 8 d antepartum), on d 1, and in wk 4 and 14 PP. Blood samples were collected every 2 wk during this entire period. Liver samples were analyzed for mRNA abundance of genes related to carbohydrate metabolism (pyruvate carboxylase, PC; phosphoenolpyruvate carboxykinase, PEPCK; citrate synthase, CS), fatty acid biosynthesis (ATP citrate lyase, ACLY) and oxidation (acyl-CoA synthetase long-chain, ACSL; carnitine palmitoyltransferase 1A, CPT 1A; carnitine palmitoyltransferase 2, CPT 2; acyl-coenzyme A dehydrogenase very long chain, ACADVL), cholesterol biosynthesis (3-hydroxy-3-methylglutaryl-coenzyme A synthase 1, HMGCS1), ketogenesis (3-hydroxy-3-methylglutaryl-coenzyme A synthase 2, HMGCS2), and of genes encoding the transcription factors peroxisome proliferator-activated receptor alpha (PPARalpha), peroxisome proliferator-activated receptor gamma (PPARgamma), and sterol regulatory element binding factor 1 (SREBF1). Blood plasma was assayed for concentrations of glucose, BHBA, nonesterified fatty acids, cholesterol, triglycerides, insulin, insulin-like growth factor-I, and thyroid hormones. In both groups, plasma parameters followed a pattern usually observed in dairy cows. However, changes were moderate and the energy balance in cows turned positive in wk 7 PP for both groups. Additionally, the energy balance and milk yield were similar for both groups after parturition onwards. Significant group effects were found at drying off, when plasma concentrations of triglycerides were higher in LB than in HB, and in wk 4 PP, when plasma concentrations of glucose and IGF-I were lower in HB than in LB. Similarly, moderate changes in mRNA expression of hepatic genes between the different time points were observed, although HB cows showed more adaptive performance than LB cows based on changes in mRNA expression of PEPCKc, PEPCKm, CS, CPT 1A, CPT 2, and PPARalpha. Part of the variation measured in this study was explained by parity. Significant Spearman rank correlation coefficients between the variables were not similar at each time point and were not similar between the groups at each time point, suggesting that metabolic regulation differs between cows. In conclusion, metabolic regulation in dairy cows is a dynamic system, and differs obviously between cows at different metabolic stages related to parturition.
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PMID:Variation in hepatic regulation of metabolism during the dry period and in early lactation in dairy cows. 1938 50