California scientists using the latest techniques in genetic engineering have synthesized human growth hormone, a discovery that could lead to production of the chemical that enables dwarfed children to reach normal height.
The synthesized hormone also might prove valuable in healing burns, wounds, bleeding ulcers and broken bones and in combating bone deterioration, or osteoporosis, in the aging.
Small-scale studies have indicated that human growth hormone -- somatotropin -- might promote cell growth and healing in all these conditions.
But the hormone can be obtaned now only in minute amount from the pea-sized pituitary glands of cadavers. The supply is so small that almost all of it must be used to help children who are failing to grow because of pituitary deficiency.
Treatment of some of the children must be delayed for several years, meaning they may never reach full growth potential, because of the short supply.
"That's one reason we think this development is so exciting," Dr. John Baxter of the University of California at San Francisco said in an interview yesterday.
Synthesis of the hormone by a group under Drs. Baxter and Howard Goodman, and including Drs. Joseph Martial and Robert Hallewell, was disclosed by the university.
A report on a similar synthesis of Genentech Inc. of Palo Alto was made yesterday by Drs. David Goeddell and Peter Seeburg at a biochemistry conference at Johns Hopkins University.
Persons who have an inborn deficiency of growth hormone have been known commonly as "pituitary dwarfs," through doctors prefer the term "growth hormone deficiency" to describe the condition from which they suffer.
Such persons rarely grow taller than three to four and a half feet, but have bodies and limbs of normal proportion. There is an unrelated shortlimbed form of dwarfism caused by bone disease.
If treatment starts early enough a pituitary-def ificient child may expect to reach normal height. Doctors sometimes halt treatment when height reaches about five feet, however, so they can treat other children in need of the scarce substance.
"A child may need treatment anywhere from once a day to once a week," explained Dr. Claude Migeon, head of pediatric endocrinology at Johns Hopkins. "And it takes just about one pituitary gland to produce enough material for one injection."
There are still many steps ahead before medically useful material can be produced. These include extracting and purifying the new symthetic hormone, and testing it in animals before testing it in humans.
But doctors and scientists at the University of California and Johns Hopkins agreed there is a good chance that a child may be treated with this man-made hormone in two years.