The methods of determining most of the intermediate metabolites of glycolysis are established, but there are certain discrepancies in the results which include the large differences in the concentrations of pyruvate and fructose diphosphate observed in extracts of rat liver (compare Hohorst, Kreutz & Bucher, 1959, with Threlfall & Stoner, 1961. The most likely source of the differences appears to be the sampling procedure and in this paper the effects of a number of procedures on the content of several intermediate metabolites of glycolysis are described.
METHODSRat&. Black and white, hooded, male rats weighing 100-250 g were used for most experiments, but 40 g rats were used for freezing whole. The animals were fed on Medical Research Council diet no. 41b, which contains approximately 58% carbohydrate, 16% protein, 2-5 % oil, 4.7 % ash and 11-8 % water.Means of producing unconsciou8fen8 Ether anaesthesia. Rapid anaesthesia associated with minimal disturbance of the rat was achieved as follows. A layer of cotton-wool about 2 cm thick was placed inside a 1-5 1.desiccator at 23-25' C, and a wire gauze was superimposed. Ether was poured on to the gauze and cotton-wool until the latter was saturated. The rat was then put on to the gauze and the lid of the desiccator was adjusted so that there was about 2 mm overlap through which vapour could escape. Air entered through a perforated rubber bung which replaced the stopcock. After inhaling the mixture of ether and air for 60-75 sec the animal became unconscious. It was then transferred in the desiccator to a room maintained at 40 C and, after a total time of anaesthesia of 75-120 sec, it was removed and the appropriate tissue excised (see below). About 70 % of the rats appeared undisturbed during the induction of anaesthesia, 25 % moved about more than normal and 5-10 % struggled violently. In certain experiments oxygen or nitrogen was admitted through a glass tube inserted through an additional hole in the stopper to the level of the wire gauze.Nembutal (pentobarbitone) anaesthesia. Doses of 1-6 mg were injected intraperitoneally. Anaesthesia was sufficiently deep to remove tissue after 10-15 min.
Plasma calcium, phosphorus, alkaline phosphatase, total protein, and albumin were measured during pregnancy in a group of Asian women living in the south of England and in a control group. The Asian women had slightly lower mean plasma calcium concentrations than the control group. Exposure of Asian women to sunshine appeared to be low, and it was inferred that they probably had little endogenous synthesis of cholecalciferol as a result. Both Asian and control subjects ingested similarly low amounts of vitamin D. The Asian women consumed greater amounts of phytate and vegetable fibres than the controls, and it is suggested that these substances may reduce absorption of insoluble lipids (including cholecalciferol) and calcium in a setting where the dietary intake and endogenous synthesis of vitamin D are already borderline for the subject's requirements.
SUMMARY
1. The urinary sodium output in adrenalectomized rats maintained on DCA and cortisone varies closely with the intake of sodium, in spite of a constant level of hormone administration.
2. There was evidence of lack of control of body sodium and potassium at both high and low extremes of sodium intake used.
3. It is argued that the results presented are evidence of (a) extra-adrenocortical control of sodium metabolism, and (b) increased adrenocortical secretion following sudden changes in dietary sodium.
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