Abstract
Since extensive experimentation has failed to reveal a reaction of the normal animal to cortical hormone administration, it has become increasingly clear that for the time being, adrenalectomized animals must be used for standardization purposes. There is no known criterion for determining accurately the degree of insufficiency from which an adrenalectomized animal is suffering, and consequently standardization cannot be based on the return of an animal suffering from adrenal insufficiency to a normal physiological condition. We have, therefore, accepted the other alternative, that is the maintenance of normal physiological condition in the adrenalectomized animal. During recent metabolic studies on bilaterally adrenalectomized dogs, permitted to go into adrenal insufficiency by the withdrawal of daily injections of cortical hormone, it was noted that the earliest indication from normality is a rise in the blood non-protein and in the urea nitrogen. 1 We have utilized this observation as a basis for biological assay of the extracts.
Adult dogs, 6 to 10 kg. body weight are selected, free of infection and worm infestation. They are adrenalectomized in 2 stages, and the success of the operation is established after complete healing of the wounds by production of insufficiency symptoms by withdrawal of extract. The dogs are then placed in separate cages and given 0.5 cc. extract per kilo in 2 equally divided doses daily, morning and evening, subcutaneously until it is demonstrated that the blood non-protein-nitrogen (or urea) is at a normal and constant level, that the weight is maintained, the food properly eaten, and the clinical condition in every respect normal. The ration given is constant and consists of 80 calories per kilo per day of Bal-Ra dog ration with 1 cc. cod liver oil 3 times weekly and 1 gm. vitavose per kilo 3 times weekly on alternate days.
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