PREPARATION OF ADRENOTROPIC EXTRACTS AND THEIR ASSAY ON TWO-DAY CHICKS11

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Abstract
A method for assaying adrenotrophic preps. on 2-day chicks is described. Chicks are injected subcut. daily for 5 days. The total amt. of a pituitary prep. required to increase wt. of the adrenal by 25% when injs. are thrice daily, or one-half the amt. required for a 25% increase when injs. are only once daily, was selected as the unit of adrenotrophic or corticotrophic activity. In chicks, as in rats, adrenal wt. increases in proportion to the 1st power of the dosage. Potent preps. induce both hypertrophy and hyperplasia of cortical cells. Numerous rats and pigeons and over 800 chicks were used in these tests. When administered by inj. at nearly lethal dosage levels the following substances caused little or no enlargement of the adrenals of these chicks: thyroxin, insulin, estrone, dihydroestrone, testosterone, desoxycorticosterone, formaldehyde, ammonia, casein, Zn and CuSO4 KCl. Thyroidectomy did not alter the degree of the adrenal response even when pituitary fractions with high thyrotrophic content were used. Hy-pophysectomy did not prevent adrenal enlargement although it decreased the degree of the response. A method of preparing highly potent adrenotrophic fractions essentially free from prolactin, thyrotrophin and gonadotrophin is presented. The method is based on solubility in 65% ethanol and at pH 3.5 in water with subsequent division of the pH 3.5 extract into soluble and insoluble fractions by dialysis. The possible identity of this principle with still other pituitary principles is considered.