Science: Simulated ACTH

For years hundreds of chemists have been trying to solve one of organic chemistry’s toughest problems: artificial synthesization of a compound with all the biological (and hence medical) properties of ACTH (adrenocorticotropic hormone). Last week the University of Pittsburgh announced that a research team headed by Dr. Klaus Hofmann, 49, had turned the trick.

The big difficulty was that the ACTH molecule is a protein, a long chain of amino acid groups linked together in a special sequence like a phrase in telegraphic code. If the code is not reproduced properly, synthetic ACTH will not do the magical things in the human body that natural ACTH does. Natural ACTH has 39 amino acid groups. Dr. Hofmann’s synthetic copy has only 23, but this part of the chain seems to function biologically as well as the whole—somewhat as if a coded message were pruned of unnecessary words before being sent.

ACTH is produced by the pea-sized pituitary gland at the base of the brain. It seems to be a hormone’s hormone; when the blood carries it to the adrenal glands on the kidneys, it stimulates the production of many other hormones that regulate vital functions of the body, including proper utilization of foods. The natural substance is extremely expensive because only minute amounts can be extracted from the pituitary glands of slaughtered animals. Dr. Hofmann does not promise that his success will lead to cheap synthetic ACTH manufactured in large quantities for medical use, but it is certainly a step in that direction.