Failure to Cure or Prevent Graying of Rats with p-Amino Benzoic Acid. ∗

Abstract

Ansbacher 1 has reported that p-amino benzoic acid would cure the characteristic graying of areas of the pelage of rats maintained on a vitamin B deficient diet supplemented with thiamin hydrochloride, riboflavin, pyridoxin hydrochloride, calcium pantothenate, nicotinic acid, inositol and choline chloride. On the appearance of this paper a considerable number of characteristically grayed rats were available to us for experimentation. They had been raised on a somewhat different ration than that employed by Ansbacher, for they received a vitamin B deficient diet supplemented with only three substances, to wit: thiamin hydrochloride, riboflavin and pyridoxin hydrochloride. They were divided into four groups as follows:

(1) Controls: Animals continued on the same diet and supplements which had produced the graying.

(2) Animals receiving daily, in addition to the 3 supplements mentioned, 100 μg pantothenic acid.

(3) Animals receiving daily, in addition to the 3 supplements mentioned, 3 mg of p-amino benzoic acid.

(4) Animals receiving daily, in addition to the 3 supplements mentioned, both 100 μg of pantothenic acid and 3 mg of p-amino benzoic acid.

After 25-30 days on the diet, a marked darkening of the fur amounting practically to a cure (only “stippling” remaining) was noted in the group supplemented with calcium pantothenate alone and with calcium pantothenate plus p-amino benzoic acid. The animals receiving p-amino benzoic acid alone were not altered in appearance and were indistinguishable from the controls. There was an evident stimulus to growth as well as cure of the graying in the animals supplemented with the calcium pantothenate alone or the pantothenate and p-amino benzoic acid. The p-amino benzoic acid alone, which had no influence on the graying, also evoked no growth response.

In spite of the negative curative efforts just enumerated, there remained the possibility that graying could be produced with the exact Ansbacher diet regardless of the fact that it was supplemented with 500 μg of calcium pantothenate daily and that such graying could be prevented or cured with p-amino benzoic acid.