Melatonin in humans—where we are 40 years after its discovery by Michal Karasek
Key
words: pineal gland, melatonin
Abstract
Although the pineal gland was
well known for more than 2000 years and has been documented
since Galen (130–200 AD), for many centuries different
theories concerning its function were presented. The organ was
believed to be a sphincter (ancient Greeks), the point at which
the soul preeminently controls the body (Descartes, 1596–1650),
a rudimentary organ (up to the 19th
century), and a gland having endocrine function. Endocrine function
of the pineal was postulated already at the end of 19th
century and the beginning of the 20th
century with the notion of antigonadotropic pineal influence,
and the functional cooperation between the pineal and hypothalamo-hypophysial
axis, but no secretory substance responsible for the gland function
was known. In 1958 Lerner and coworkers succeeded in isolating
from bovine pineal glands the compound termed melatonin because
of its blanching effect on melanophores. This discovery constituted
the milestone for further pineal research. Since then the knowledge
of the structure and function of the pineal gland has tremendously
increased, especially during the last two decades. However,
it should be stressed that many problems in pineal research
still must be solved. In this paper, the recent knowledge on
the role of melatonin in humans is briefly presented.
