Enzyme Activities In Mice Research Articles

Serum enzyme activities in mice fed a high level of ascorbic acid

Serum enzyme activities were compared in Swiss albino male mice receiving either untreated drinking water or drinking water containing 250 mg L-ascorbic acid per 100 ml. Mice on the ascorbate regimen consumed approximately 12 mg ascorbic acid per day. After four weeks, mice receiving the supplementary ascorbic acid had higher mean serum lactate dehydrogenase activity than those receiving untreated water. Supplementary ascorbic acid appeared not to influence serum amylase, lipase, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, acid phosphatase, or alkaline phosphatase activities.

Changes in the Activities of Enzymes, Especially Lactate Dehydrogenase, in Endotoxin‐Poisoned Mice

AbstractCarbohydrate metabolic disorders were investigated by means of enzyme activities in mice (ddYS) injected intraperitoneally with endotoxin from Salmonella typhimurium. The mice exhibited hyperglycemia 2 hr after administration of endotoxin and hypoglycemia at 18 hr. Activity of hepatic phosphorylase in the endotoxin‐poisoned mice at 2 hr was slightly higher than that in the control mice, whereas the level of this activity was not significantly different from that in the controls after 18 hr. Glucose‐6‐phosphatase activity in the poisoned mice increased by 2 hr after injection, but decreased by 18 hr.The blood lactate level in the poisoned mice transiently decreased until 3 hr after injection, but the mice exhibited a marked lactacidemia by 8–24 hr. The time course of lactate dehydrogenase (LDH) activity in various tissues was examined in mice injected with endotoxin. The activity of hepatic LDH declined to about two‐thirds of that of the control mice after 16 hr, and was restored to the normal level by 48 hr. LDH in the cardiac muscle was markedly activated (by about 37%) in the early period (3–6 hr) after administration of endotoxin, and this activity gradually declined. However, the activity of LDH in the skeletal muscle showed a tendency similar to the rise and fall of the levels of blood lactate, and was restored to the normal value at 72 hr after injection. On the other hand, the serum LDH activity in the poisoned mice increased about 1.75‐fold by 16 hr after injection. Mice injected with endotoxin exhibited a leakage of the isozymes LDH 3 and 5, but the origin of the leakage is uncertain. Similar elevation in the activities of transaminases (GPT and GOT) and malate dehydrogenase was found in the mouse serum at 16 hr after injection of endotoxin.

Endotoxic glycolipid as a potent depressor of the hepatic drug-metabolizing enzyme systems in mice.

Inhibitory effects of the endotoxic glycolipid from Salmonella minnesota R595 on hepatic drug-metabolizing enzyme activities in mice were investigated, and the depressor activity of the glycolipid in the enzyme systems was confirmed. Among degradation products of lipopolysaccharides tested, lipid A preparations derived from the mild acetic acid hydrolysates of lipopolysaccharides were the most active, but the lipid A fractions prepared from the hydrolysates with 1 N-HCl were almost inactive. A degraded polysaccharide fraction from E. coli lipopolysaccharide was inactive. The activities of the glycolipid and the lipid A preparation were markedly reduced by treatment with alkaline-hydroxylamine, mild alkali or hydrazine. The data showed that the lipid A moiety of the glycolipid may be responsible for the inhibitory activity on the hepatic drug-metabolizing enzyme systems.

Drug interactions. I. Effects of repeated administration of combined analgesic on its pharmacological activity and on hepatic drug-metabolizing enzyme activities in mice.

In order to elucidate the interactions of the components of an aminopyrine (28.9 mg)-phenacetin (57.8 mg)-phenobarbital (13.3 mg) preparation on repeated administration (100 mg/kg of body weight) to mice, the analgesic activity of the preparation, the hepatic drug-metabolizing enzyme activities and the plasma concentrations of phenobarbital, phenacetin and acetaminophen in mice dosed repeatedly for 7 days were estimated in comparison with a single dose group. The analgesic activity was significantly decreased and the liver drug-metabolizing enzyme activities were markedly enhanced after the repeated treatment as compared with the results obtained following a single dose. The plasma levels of phenacetin were markedly lower at both 45 and 90 min in the repeated dose group, while the levels of acetaminophen and its glucuronide were higher in mice dosed repeatedly than in the single dose group 45 min after intraperitoneal injection, but lower after 90 min. The plasma concentrations of phenobarbital 45 and 90 min after the combined drug were not significantly different in the single and repeated dose groups. When the induction rate of the drug-metabolizing enzymes by the combined drug was compared with that by phenobarbital alone, there was a clear-cut correlation (r=0.986 for repeated dosing and r=0.985 for a single dose). This strongly suggests that phenobarbital in the combined analgesic induced metabolic inactivation of the other component drugs without significant enhancement of its own metabolism, while aminopyrine and phenacetin had no such effect.

Catecholamines: Strain differences in biosynthetic enzyme activity in mice

In five strains of inbred mice, activities of phenylethanolamine N -methyl transferase and tyrosine hydroxylase and amounts of norepinephrine and epinephrine in the adrenal gland vary markedly. Tyrosine hydroxylase activity in the brain also varies widely. The fact that these measures vary independently of each other suggests that several genetic factors are involved. The finding of genetic differences affecting catecholamine synthesis has implications for the study of catecholamine regulatory mechanisms and the relationship between catecholamines and behavior.

Influence of gonadectomy, sex hormones and other factors, on the activity of certain glycosidases in the rat and mouse.

SUMMARY 1. The rise with age in the α-mannosidase, β-galactosidase, β-N-acetylglucosaminidase and βglucuronidase activities in the epididymis of mice and rats has been examined. Enzyme activities in both species reached a maximum at an age of 12–14 weeks. 2. Ovariectomy caused a considerable drop in all uterine enzyme activities in mice. Administration of oestrone to such mice restored the activities to intact levels. 3. Castration of both mice and rats greatly reduced the enzyme activities in the epididymis. Prolonged injection of testosterone raised all the activities, although not to intact levels. 4. Injections of menthol, chloroform and carbon tetrachloride caused changes in enzyme activity analogous to those already observed with β-glucuronidase, although there were quantitative differences in the response of each enzyme. 5. A study of the effects of partial hepatectomy, and to a lesser extent, injection of carbon tetrachloride on the glycosidase activities in ovariectomized mice provides evidence for the action of extraovarian oestrogen. 6. Changes in enzyme activities of the epididymis were seen after partial hepatectomy or injection of carbon tetrachloride in castrated male mice. 7. The qualitative behaviour of all four enzymes in response to the action of extrinsic agents suggests that they exert similar functions in the body, and that these may well lie in the field of mucopolysaccharide catabolism.