Cytochrome P450-catalyzed enzyme activity in cell culture was investigated as a bioassay for 2,3,7,8-tetrachlorodibenzop-dioxin (TCDD) equivalents in environmental mixtures of polychlorinated dibenzo-p-dioxin (PCDD), dibenzofuran (PCDF), and biphenyl (PCB) congeners. A problem with the use of enzyme induction is that certain congeners are unable to induce P4501A enzyme activity to the same maxi...

We studied the kinetics of corticotropin (ACTH) induction of mitochondrial cytochromes P450scc and P450c11 and their electron transport proteins, adrenodoxin and adrenodoxin reductase, in bovine adrenal cortex cells in primary culture. The mRNA levels of these enzymes increase and reach a peak within 3-12 h after ACTH addition. The protein levels of adrenodoxin reductase and P450scc show an inc...

The induction of tryptophan pyrrolase in chick liver by hydrocortisone was studied in copper- and magnesium-deficient chicks. Magnesium deficiency did not influence the induction of the enzyme, whereas copper deficiency significantly decreased it. These results suggest that tryptophan pyrrolase of chick liver, like that in Pseudomonas, is a copper-containing enzyme.

background: intracytoplasmic sperm injection (icsi) is an advanced technique employed in assisted reproductive clinics for treatment of infertile couples. the reproductive endocrinologists try their level best to identify factors that enhance success rate after icsi. objective: to compare estradiol progesterone ratio on ovulation induction day amongst pregnancy outcome groups following icsi. ma...

Induction of coumarin 7-hydroxylation, catalyzed by CYP2A5 in mice and CYP2A6 in humans by various known in vivo murine inducers and modifiers, was compared in human and mouse hepatocytes in culture. Phenobarbital and rifampicin were efficient inducers (up to 10-fold induction) after 48-h treatment in murine cultured hepatocytes, whereas the enzyme activity in human hepatocytes was much more re...

Enzyme induction in Escherichia coli is stimulated by certain 5-amino-2,4-bis(substitutedamino)pyrimidines (Kunkee, 1960a). Other 2,4diaminopyrimidines have been reported to be antagonists of folic acid (Hitchings et al., 1952; Doctor, 1956). Since there are indications that the stimulation of enzyme induction involves nucleic acid metabolism (Kunkee, 1960b) and since folic acid is involved in ...

In fasting-refeeding experiments glucagon was found to inhibit the induction of rat liver glucose-6-P dehydrogenase. The kinetics of induction in the presence of glucagon indicated that the hormone decreased the rate of enzyme synthesis without altering the rate of enzyme degradation. Immunochemical titration of the amount of glucose-6-P dehydrogenase protein present in control and glucagon tre...

In fasting-refeeding experiments glucagon was found to inhibit the induction of rat liver glucose-&P dehydrogenase. The kinetics of induction in the presence of glucagon indicated that the hormone decreased the rate of enzyme synthesis without altering the rate of enzyme degradation. Immunochemical titration of the amount of glucose-6-P dehydrogenase protein present in control and glucagon trea...

the µ (mu) opioid receptors, which mediate the effects of morphine, are widely distributed in brain. the purpose of this study was to design a simple expression system for rat µ-receptor in escherichia coli (bl21). in this laboratory study, rat µ-receptor cdna was isolated from pcdna3 vector using xba1 and hind3 restriction enzymes. pet-15b was digested by nco1 restriction enzyme. µ-receptor cd...

The lipogenic capacity of rat liver is increased in animals fed a high carbohydrate, fat-free diet or by the administration of 2,2',5'-triiodo-L-thyronine. Underlying this change is a generalized induction of the enzymes involved in lipogenesis, including glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and malic enzyme, which together serve to generate the additional NADPH ...