the blood and passing it into the urine for excre-
tion from the body. Though the modern method
employs laboratory equipment that measures the
amount of glucose present in the urine, the
ancient physician relied on a far less sophisticated
approach: An unfortunate assistant tasted the
patient’s urine, with sweetness confirming the
diagnosis. More innovative or perhaps simply less
influential healers had their patients urinate on
the ground, then watched to see whether ants
swarmed to the site. When ants were attracted to
the urine, the diagnosis was “honey urine dis-
ease,” known today as diabetes.
The diagnosis unfortunately offered little hope
for treatment. Ancient healers knew honey urine
was a harbinger of death but they did not under-
stand the accountable disease mechanisms. Not
until the early 20th century did the scientists
Frederick Banting (1891–1941), Charles Best
(1899–1978), and John James Rickard Macleod
(1876–1935) discover insulin and correlate it to
pancreatic function and diabetes. Their research
ultimately demonstrated that regular injections of
a purified solution prepared with ground pancre-
atic tissue from pigs or cows, which provided
insulin, restored glucose metabolism in people
who had diabetes.
The work earned the trio the 1923 Nobel Prize in
Physiology or Medicine. More significant, it gave
the prospect of normal life to countless people oth-
erwise consigned to near-certain death. And it
threw open the door to expanded knowledge of the
role of the body’s chemical messengers in health
and in illness. Modern researchers hope to build on
this knowledge to find a cure for diabetes, a disor-
der that despite treatment remains the leading
cause of RENAL FAILUREand blindness and a signifi-
cant cause of CARDIOVASCULAR DISEASE(CVD).
Breakthrough Research and Treatment Advances
The 20th century saw the field of endocrinology
grow from the introduction of the term hormonein
1902 to amazing breakthroughs in understanding
of, and treatments for disorders of, endocrine
function and neuroendocrine interactions.
Researchers now know of nearly 100 hormones
the body produces and have developed synthetic
hormones to replace or supplement the body’s
natural hormones as treatments for conditions
such as diabetes, hypothyroidism, and osteoporo-
sis. People who have insulin-dependent diabetes
now take injections of insulin products genetically
engineered in the laboratory to emulate human
insulin’s precise molecular structure, no longer
dependent on purified extracts from animal tis-
sues. Research exploring ISLET CELL TRANSPLANTATION
shows promise for being among the therapies that
might someday allow doctors to cure diabetes.
Researchers entered other frontiers of
endocrine understanding as well. In 1935 scien-
tists finally isolated and named testosterone, the
male sex hormone. Shortly after came the discov-
ery of estrogen, the female sex hormone. A quar-
ter century later researchers had turned this
knowledge into significant advances on both ends
of the fertility spectrum, with the debut of the oral
contraceptive (birth control pill) in 1960 and the
birth of the first “test tube baby” in 1978. Both
discoveries manipulate the hormones responsible
for OVULATION, CONCEPTION, and pregnancy.
Researchers also have come to recognize that hor-
mones drive most primary cancers of the BREAST,
uterus, PROSTATE GLAND, and testicles. New thera-
pies use pharmaceutical interventions (synthetic
hormones and chemicals that mimic the structure
and action of hormones) to treat or prevent these
cancers.The Endocrine System 103