摘要:

Summary.This paper reports the results of growth tests on young white rats on diets adequate in other respects but containing varying concentrations of L‐ and D‐methionine.The following results were obtained:The concentration required for maintenance of the body‐weight was 0.10 % L‐methionine and 0.12 % D‐methionine in the diet.The effect of the D‐methionine on the growth was merely 76–84 per cent, of that of the L‐methionine.Maximal growth was obtained at a concentration of 0.25–1% L‐methionine and of 0.5C–.2% D‐methionine in the diet. D‐methionine seems to be less toxic than L‐methionine. A toxic effect on the growth (stagnation in weight) resulted at a concentration of 3.5% L‐methionine and of 5.4% D‐methionine in the diet.In default of methionine in the diet the animals had a poor appetite, which immediately improved on the addition of L‐ or D‐methionine. A maximal appetite was obtained with 0.125–1% L‐methionine or 0.125–4% D‐methionine. With higher concent

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1950.tb00676.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary.The submaxillary gland was perfused with eserinized plasma and the perfusate tested for acetylcholine on cat's blood pressure. Small amounts of acetylcholine could always be detected in the venous outflow; during stimulation of the chorda tympani there was an increase in acetylcholine content. When the perfusion fluid contained curare (Intocostrin 10‐4), stimulation of the chorda was also accompanied by an increase in acetylcholine content of the perfusate but only to about a third or a fourth of the value obtained on stimulation without curare. The average output of acetylcholine in ten experiments on cats (two minutes stimulation, 20 shocks/sec.) was 0.144 μg without and 0.050 μg with curare. It is suggested that the acetylcholine obtained in the latter case originated from the parasympathetic nerve endings in the submaxillary ganglion, since it is very unlikely that with this concentration of curare transmission occurs across the ganglion even in the presence of eserine. This assumption is further supported by pharmacological evidence and by the fact that the chorda tympani contains acetylcholine in relatively high concentration.This work was originally planned in discussions with Professor F. C. MACINTOSH, when one of us (N.E.) had the advantage of working with him at the National Institute for Medical Kesearch in London. The authors are greatly indebted to him for these discussions and for his kindness in looking over the manuscript.The investigation has been aided by a grant to one of us (N.E.) from the Swedish Medical Eesearch Coun

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1950.tb00677.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary.It is shown that saccharin and other sweetening agents may produce a slight fall of the blood‐sugar value; the phenomenon is not a constant one, it occurs more frequently after washing the mouth with the solution than after drinking it. No reaction was observed after administration of saccharin by duodenal tube. It is supposed that the reaction is released via the gustatory nerve

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1950.tb00678.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary.Following the administration of alloxan to untreated and to insulin‐treated, alloxan‐diabetic animals, only slight fluctuations of the blood sugar curve are observed as compared to those seen after administration of alloxan to the intact animals. In perfusion of cat's liver, only a faint influence of alloxan on the glycogenolysis is observed; on the other hand, a massive injury of the liver tissue is seen. The results confirm the supposition of the presence of intact beta cells as a necessary condition for the occurrence of the typical phases of the blood sugar curve after the administration of allo

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1950.tb00679.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary.When frogs in water are transferred from room temperature to low temperatures,e.g.2–3° C, the body water increases rapidly in amount until a new equilibrium is established within some few days. Further weight increase,e.g.increase in body water may occur at a low rate. This slow working part of the water retention goes parallel to a salt accumulation brought about by active uptake of NaCl through the skin from the surrounding water.Injected water is also rapidly eliminated by the kidneys in frogs living at low temperatures. Salt administered in form of hypertonic solution of NaCl is, however, not eliminated by the kidneys. The water and salt accumulation demonstrated in frogs at low temperatures is therefore probably caused by an inability of the kidney to excrete the salt taken up through the skin, the resulting hypertonicity of the blood being counteracted by retention of some of the water entering through the sk

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1950.tb00680.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1950.tb00681.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary.1It is shown that a number of substances besides glucose and ethyl alcohol (see table II) are able to make starving yeast absorb potassium (40 substances were examined and 15 caused K absorption).2All these substances with two exceptions (mannose and fructose) either form or are ether‐ or toluenesoluble and more or less volatile acids.3Common to all the substances is their ability to make the oxygen consumption rise considerably.4There seems to be a pH regulation in yeast cells, so that the cells will lose potassium if pH of the cells rises too much.5The K absorption will in most cases be appropriate as organic acids are formed from naturally occurring substances and the extracellular low pH will make the acids free and the acids will be bound in the cells as only the free acids are easily permeating.As to the mechanism of the K absorption the experiments give no information.But glycogen formation and acid formation during the absorption does not seem to be necessary, as it has been supposed.6A method is stated which makes it possible by toluene extraction in the author's extraction vessels, using WIDMARK'S principle of extraction to estimate the amount and nature of one of the lower fatty acids produced during an experiment. The amount is compared with changes of the amount of ethersoluble acids and volatile acids.7By this method it is shown that acetic acid is formed from ethyl alcohol and acetaldehyde, propionic acid from propyl alcohol and propylaldehyde, and butyric acid from butyl alcohol. The acid formation from the aldehydes is slower than from the alcohols, possibly the aldehydes are toxic.After addition of glucose one or more ether‐ and toluenesoluble acids are formed. After 15 minutes they have disappeared. The nature of the acids is discus

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1950.tb00682.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary.Experiments were carried out in which blood was trapped in the legs by means of pneumatic cuffs immediately after 10 minutes of heavy work (1,340 mkg per minute) and not released until 15 minutes after cessation of work.The effect of this auto‐transfusion of “work blood” was a pronounced increase in the pulmonary ventilation, which prior to the release had returned to a value not much above the resting value. Control experiments showed that this increase only to a minor degree was caused by the concomitant transitory changes in alveolar CO2pressure and arterial blood pressure. Breathing of pure oxygen diminished the increase in ventilation caused by the auto‐transfusion considerably.The results from these experiments, therefore, are in good agreement with the conclusion arrived at in earlier experiments, viz. that the blood during heavy work contains specific substances produced under anaerobic conditions in the working muscles and with a pronounced stimulatory effect on the vent

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1950.tb00683.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1950.tb00684.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary.It has been shown earlier that at low plasma‐thiosulphate concentrations the thiosulphate clearance of adult cats may be up to twice as high as the creatinine clearance, but that with an increasing plasma‐thiosulphate concentration this difference approximates 0. The most probable explanation is that the tubuli of adult cats can secrete thiosulphate. As no such difference has been observed in man, dog or rabbit, and as it is possible that the difference is due to differences in diet, tests were made on five kittens, two to eight weeks old, which had Received nothing but milk. Conditions were found to be exactly the same for both kittens and adult c

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1950.tb00685.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY