American Scientists Study Human Growth Mystery

Press, Volume XCVIII, Issue 29004, 19 September 1959, Page 10

American Scientists Study Human Growth Mystery

WASHINGTON. Biochemists at the University of Michigan medical centre are exploring one of nature’s bestkept secrets—the mystery of human growth. They have produced evidence indicating that growth is closely related to an “amino-acid hunger” of individual body cells. Dr. Halvor N. Christensen, chairman of the University of Michigan Department of Biological Chemistry, recently summarised the findings of his 10year research project at a meeting in Cambridge, Massachusetts, of the American Chemical Society and the American Association of Clinical Chemists. Amino acids, he says, can serve a two-fold purpose. They are the chemical building blocks

of living protoplasm and also may be used as fuel for the body. At any given moment, their use seems to be governed by the presence of certain hormones. At times these enter the cells in great quantities and then growth tends to take place. The researchers have probed into the mechanism that transmits these nutrients through the cell membrane.

Curiously, the Michigan researchers found that the direction of this transport goes from a weak solution (the blood) into a concentrated one (the cell body). This is a biological oddity which, says Dr. Christensen, "is like water flowing up hill.” He explains the activity as an “amino acid hunger.” The researchers suspect that a form

of vitamin B-6 propels the amino molecules into the rich interior of the cell.

“When a person matures and his growth potential drops off, this amino acid hunger decreases.” Dr. Christensen reports. “Then a smaller number of amino acid molecules ' are used for •growth and more are converted into energy for running the body.”

This changing mechanism may be the thing that makes us stop growing at a certain period in life, he says, and may also help to explain cancer. A cancer, eell retains its amino acid hunger and grows vigorously, to the detriment of other parts of the body.