Effects of Dietary Amino Acids on Brain Amino Acids and Transmitter Amines in Rats with a Portacaval Shunt

The etiologic relationship between disturbances in metabolism of amino acids and amines and hepatic coma was investigated by examining the effects of diets containing various mixtures of amino acids on brain amine metabolism in rats with a portacaval shunt, using a method for simultaneous analysis of amino acids and amines. Rats with a portacaval shunt were fed on four different amino acid compositions with increased amounts of various amino acids suspected to be etiologically related to hepatic coma, such as methionine, phenylalanine, tyrosine, and tryptophan. The animals were killed 4 weeks after operation. During the experimental period, these animals did not become comatose, but exhibited various behavioral abnormalities. Marked increase in the plasma and brain levels of the augmented amino acids, especially methionine and tyrosine, were observed in rats with a portacaval shunt. Brain noradrenaline, dopamine, and serotonin levels were significantly decreased when the brain tyrosine level was increased. These results indicate that in rats with a portacaval shunt the dietary levels of amino acids greatly influence the brain levels of both amino acids and transmitter amines.     

Lignans of Larix leptolepis

Five lignans have been isolated from wood of Larix leptolepis. They are identified as 1-(4-hydroxy-3-methoxyphenyl)-2-4-[2-formyl-(E)-vinyl]-2-methoxyphenoxy-propane- 1,3-diol, 1-(4-hydroxy-3-methoxyphenyl)-2-2-methoxy-4-[1-(E)-propen-3-ol]-phenoxy- propane-1,3-diol, 1-(4-hydroxy-3-methoxyphenyl)-2-(4-formyl-2-methoxyphenoxy)-propane-1,3-diol, 1,2-bis-(4-hydroxy-3-methoxyphenyl)-propane-1,3-diol and a trilignol, leptolepisol C.     

Induction of L-lysine-2-oxoglutarate reductase by glucagon and glucocorticoid in developing and adult rats in vivo and in vitro studies

L-Lysine-2-oxoglutarate reductase (EC 1.5.1.8, NADP⁺) in the liver of adult rats increased 4–5-times when the animals were treated with alloxan. In diabetic rats injection of insulin or adrenalectomy prevented the increase in enzyme activity. The activity of the similar enzyme in kidney was not changed by these treatments. The enzyme activity in primary cultured adult rat hepatocytes was also induced by addition of dexamethasone and glucagon together, and glucagon could be replaced by dibutyryl cyclic AMP. Insulin inhibited the induction. The hormonal induction was also inhibited by actinomycin D and by cycloheximide. During development of rats, fetal liver showed very low activity, but the activity appeared on day 1 after birth and then increased rapidly, reaching the adult level by day 5. The activity of the kidney enzyme increased more slowly and reached the adult level 1 month after birth. Intra-uterine injection of glucagon caused precocious induction of the liver enzyme in fetuses. These results indicate that the activity of L-lysine-2-oxoglutarate reductase in the adult liver and in part in neonatal liver also, is controlled by both glucagon and glucocorticoid.     

Continuous culture of reuber hepatoma cells in serum-free,arginine-, glutamine-and tyrosine-deprived chemically defined medium

Summary The rat hepatoma cell line, H4-II-E, was grown serially over a I-year period and about 30 passages in arginine-, glutamine-, and tyrosine-deprived and ornithine-supplemented Eagle's mininum essential medium with no supplements other than biotin. The adapted cel line, R-Y121B, proliferates in the above mentioned medium with a doubling time of about 4 days and maintains hepatic “marker” enzymes such as tyrosine aminotransferase, phenylalanine hydroxylase, and all the enzymes of the urea cycle. This work was supported in part by Grant-in-Aid for Cancer Research 301050 and Science Research Grant 337013 from the Ministry of Education, Science and Culture, Japan.     

Reaction of some D-glucobioses with 2,2-dimethoxypropane

Laminarabiose, cellobiose, and gentiobiose were acetonated with 2,2-dimethoxy-propane under various conditions. Two isopropylidene acetals in which the reducing D-glucose residue had the furanoid form were obtained from laminarabiose, and two, in which the reducing D-glucose residue formed the acyclic dimethyl acetal, from cellobiose. Gentiobiose gave both types of isopropylidene compound.     

Metabolites of mating pheromone,rhodotorucine A, by a cells of Rhodosporidiumtoruloides

Rhodotorucine $\text{A}$ which induces mating tube formation of $\text{a}$ cells in $\text{Rhodosporidium}\text{toruloides}$ is metabolized rapidly by $\text{a}$ cells. By use of labeled rhodotorucine $\text{A}$, the degradation was found to be proteolytic. Two peptide fragments Tyr-Pro-Glu-Ile-Ser-Trp-Thr-Arg and Asn-Gly-Cys(S-farnesyl) were identified as the metabolites. Proteolysis of the pheromone mainly occurred on the cell surface. Culture filtrate of $\text{a}$ cells at log phase did not metabolize rhodotorucine $\text{A}$.     

Phosphorus-31 relaxation times of 2,3-diphosphoglycerate in intact human erythrocytes

The reciprocals of the spin-lattice relaxation times (T₁s) of the 2-P and 3-P nuclei of 2,3-diphosphoglycerate (DPG) increased linearly as percent DPG bound was raised in model hemoglobin solutions. The 2-P T₁ was slightly greater in intact erythrocytes than in model solutions under similar experimental conditions. The change in the 3-P T₁ with cellular deoxygenation was anomalous indicating that this nucleus should not be used to estimate DPG binding inside intact erythrocytes.