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sexta-feira, 11 de novembro de 2011
terça-feira, 8 de novembro de 2011
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domingo, 6 de novembro de 2011
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quinta-feira, 3 de novembro de 2011
A Hormone Ensures its Future
Publications and Media Relations Department, Rehovot, Israel 76100 Tel: 972-8-934-3852 / 56 Fax: 972-8-934-4132
http://wis-wander.weizmann.ac.il news@weizmann.ac.il November 2011
Much of the body’s chemistry is
controlled by the brain – from
blood pressure to appetite to food
metabolism. In a study published
recently in Developmental Cell, a team
of scientists led by Dr. Gil Levkowitz
of the Weizmann Institute has revealed
the exact structure of one crucial brain
area in which biochemical commands
are passed from the brain cells to the
bloodstream and from there to the
body. In the process, they discovered a
surprising new role for the “hormone
of love,” showing that it helps to direct
the development of this brain structure.
The area in question, the neurohypophysis,
is an interface between
nerve fibers and blood vessels located
at the base of the brain. Here, some
of the major brain-body interactions
take place: Hormones released from
nerves into the blood vessels regulate
a series of vital body processes,
including the balance of fluids and
uterine contractions in childbirth.
Although the neurohypophysis
has been studied for more than a
century, the scientists in the Weizmann
Institute-led study developed new
genetic tools that enabled them to
examine the exact three-dimensional
arrangement of this brain structure
and clarify the cellular and molecular
processes leading to its formation.
Since the human neurohypophysis is
exceedingly complex, the scientists
performed the research on live
embryos of zebrafish. These fully
transparent embryos offer a unique
model for studying the vertebrate
brain, lending themselves to genetic
manipulation with relative ease and
enabling researchers to observe the
actual formation of a neurohypophysis
under a microscope.
The study revealed a surprising
new function for the hormonal
messenger oxytocin, dubbed the
“hormone of love” because, in addition
to controlling appetite and such female
reproductive behaviors as breastfeeding,
it is also involved in mother-child
and mate bonding. The scientists
showed that oxytocin, one of the two
major hormones secreted in the adult
neurohypophysis, is involved in the
development of this brain area already
in the embryo. At this stage, the
oxytocin governs the formation of new
blood vessels. “The messenger helps
to build the road for transmitting its
own future messages,” says Levkowitz.
Developmental Cell highlighted the
study’s findings in a preview headlined,
“The Hormone of Love Attracts
a Partner for Life.”
These findings provide an
important advance in basic research
because they shed light on fundamental
brain processes, but in the future they
might also be relevant to the treatment
of disease. Since the neurohypophysis
is one of only a few portions of the
brain able to regenerate after injury, an
understanding of how it is formed may
one day help achieve such regeneration
in other parts of the central nervous
system.
The research was conducted in
Levkowitz’s lab in the Molecular Cell
Biology Department by Ph.D. student
Amos Gutnick together with Dr. Janna
Blechman. The Weizmann scientists
worked in collaboration with Dr. Jan
Kaslin of Monash University, Australia;
Drs. Lukas Herwig, Heinz-Georg
Belting and Markus Affolter of the
University of Basel, Switzerland; and
Dr. Joshua L. Bonkowsky of the
University of Utah, United States. ❙
Dr. Gil Levkowitz’s research is
supported by the Dekker Foundation;
the Kirk Center for Childhood Cancer
and Immunological Disorders; and
the Irwin Green Alzheimer’s Research
Fund. Dr. Levkowitz is the incumbent
of the Tauro Career Development
Chair in Biomedic