Depletion of pituitary corticotrophin by reserpine and by a nitrogen mustard.

A single intraperitoneal injection of reserpine (2.5 mg./kg.) into rats produced a fall in the corticotrophin concentration of the pituitary to 30% of the resting value; recovery was not far from complete at 40 hr. A single injection of a nitrogen mustard caused an even greater loss of pituitary corticotrophin; 24 hr. after the injection the concentration was 10% of the resting value. There is no reason to assume that the effect of reserpine is due to an interference with storage of ACTH in the tissue and is not simply due to the fact that the drug acts as a stressing agent. The shape of the curve representing the fall in pituitary ACTH during the early phases of a sudden stress may be very similar to that of the fall in adrenal ascorbic acid produced by the released ACTH. This suggests that, under these circumstances, resynthesis is slow and the diminishing stores of ACTH in the pituitary reflect mainly the release of the hormone.