Endocrinology Welcome

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EndocrinologyWelcome A little bit about
me Expectations for the course May be the one of
hardest class you take at LSU Will prepare you
for MCAT GRE Post graduate studies I dont give
GRADES. YOU earn your grades

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W Change in LSU policies Can only drop one
class per year

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Look at Syllabus

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Endocrinology Exams-Fill in the blank, short
answer and essay Not mere regurgitation Today-
Introduction and photos Responsible for lecture
material Attend class

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• Quiz from last year
• What is endocrinology.
• Name one endocrine organ

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Endocrinology is the study of chemical
communication systems that provide the means to
control a huge number of physiologic processes.
Hormone producing cells Hormones Receptors

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How is it that humans and animals maintain quite
constant blood concentrations of glucose
throughout their lives despite wildly varying
frequencies of meals? If your blood glucose
concentration drops much below 1 mg per ml, your
neurons will begin to misbehave, leading
ultimately to coma and death. Yet skipping
breakfast is rarely life-threatening.
The answer ??
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Two systems control all physiologic processes
The nervous system - point-to-point control
through nerves. electrical in nature and
fast.The endocrine system broadcasts hormonal
messages Cell need a receptor for the hormone in
order to respond. Act together to regulate
physiology.
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Endocrinology is the study of hormones, their
receptors and the intracellular signaling
pathways they invoke. Be familiar with the
locations of the endocrine organs Hypothalamus P
ituitary Gland Thyroid Gland Parathyroid
Gland Adrenal Gland Testes
Ovaries Adipose Tissue Pine
al Gland
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Think outside the OLD BOX- In addition to the
classical endocrine organs, many other cells in
the body secrete hormones. Myocytes
Adipose Tissue Liver Neurons
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If the term hormone is defined broadly to include
all secreted chemical messengers, then virtually
all cells can be considered part of the endocrine
system.
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All pathophysiologic events are influenced by
the endocrine milieu All "large" physiologic
effects are mediated by multiple hormones acting
in concert There are many hormones known and
little doubt that others remain to be discovered.
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The BASICS
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Hormones, Receptors and Target Cells Hormones
are chemical messengers secreted into blood or
extracellular fluid by one cell that affect the
functioning of other cells. However, a given
hormone usually affects only a limited number of
cells, which are called target cells.
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In other words, a particular cell is a target
cell for a hormone if it contains functional
receptors for that hormone, and cells which do
not have such a receptor cannot be influenced
directly by that hormone. Reception of a radio
broadcast provides a good analogy.
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Hormone receptors are found either exposed on
the surface of the cell or within the cell,
depending on the type of hormone.
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DEFINED ON DISTANCE A traditional part of the
definition of hormones described them as being
secreted into blood and affecting cells at
distant sites. However, many of the hormones
known to act in that manner have been shown to
also affect neighboring cells or even have
effects on the same cells that secrete the
hormone.
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Endocrine Paracrine Autocrine Know some
examples of each Insulin??
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Two important terms are used to refer to
molecules that bind to the hormone-binding sites
of receptors Agonists are molecules that bind
the receptor and induce all the post-receptor
events that lead to a biologic effect. Natural
hormones are themselves agonists and, in some
cases, more than one distinct hormone binds to
the same receptor.
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Antagonists are molecules that bind the receptor
and block binding of the agonist, but fail to
trigger intracellular signalling
events. Hormone antagonists are widely used as
drugs.
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Hormones are inevitably named shortly after
their discovery, when understanding was
rudimentary. They are often named for the first
physiologic effect observed or for their major
site of synthesis.
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Endocrinology-some history First published
experiment by Berthold in 1849 Now great
expanding area of research Only recognized in
last 10 years that Adipose Tissue (FAT) is an
endocrine hormone.

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Berthold experiment Results Transplanted
testis were functional, so not dependent on
direct innervations for activity Also discovered
compensatory hypertrophy- increase in size of an
organ to compensate functionally for loss of
other organ Castrated animals-testis larger than
controls

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Berthold experiment What was going on? Various
possibilities Extracts from testes could
functionally replace testes in castrated
animal Testosterone purified in 1935

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Review Endocrinology Hormones can be defined
on how they act over certain distances. Hormones
have receptors-cell surface or inside
cells Agonist and Antagonist Berthold
Experiments

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Read Course description and syllabus Look at
course web site Be familiar with terms we talked
about today Hormone Receptor Endocrine,
paracrine, autocrine Come and get your photo
taken-MANDATORY