THE KETOGENIC ACTIVITY OF CORTICOTROPIN, A PRESUMED EXTRA-ADRENAL ACTION1

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Abstract
The ketogenic response to protein ACTH, oxyeel-adsorbed ACTH, Corticotropin A, mixtures of purified corticotropin peptides, pepsin and chymotrypsin digestion products of β-corticotropin, β-MSH and commercial vasopressin has been tested in intact rats, according to techniques previously described. It has already been shown that corticotropin induces ketosis in adrenalectomized rats and hence the response studied is presumed to be an extra-adrenal one. Oxycel corticotropin, Corticotropin A and various mixtures of corticotropin peptides (α1 – α2 and γ-pool corticotropin, American Cyanamid Company) exhibited high ketogenic activity whereas a protein ACTH (Armour), three products of pepsin digestion and one of chymotrypsin digestion and fraction δ-1 of the American Cyanamid Company had markedly decreased activity. The ketogenic active corticotropins also were known to have ascorbic acid depleting and MSH activities, as did the peptides from pepsin digestion. The chymotrypsin peptide was devoid of biological activity. Treatment of ketogenic active peptides by boiling in 0.1N NaOH resulted in loss of ascorbic acid depleting and ketogenic activities but not MSH activity whereas mild alkali treatment had no effect on these activities.