Download Hormone

Principles of Endocrinology
Department of Endocrinology
First Affiliated Hospital
Sun Yet-sen University
Cao Xiaopei
Principles of Endocrinology

Glands

Hormones
Endocrine

hormones from specialized cells in
glands or tissue are secrected and
transported in the blood to a
distant site of action(classic
“endocrine” effect), or act directly
upon nearby cells which is called
“paracrine” activity.
Exocrine

products from glands are
secrected externally or into a
lumen, such as the
gastrointestinal tract.
Endocrine System
Elements of endocrine system:
 Endocrine organs
 APUD system
 Hormonal secrentory cells
Major endocrine organs and common endocrine problems
Other endocrine sites
Islet：insulin（βcell）、glucagon（αcell）
somatostatin、VIP…
Mucosa in GI tract：
gastrin、cholecystokinin、secretin、VIP…
Kidney: 1,25-(OH)2D3, Renin，EP，PG…
Lung：APUD…
Heart：natriuretic peptide…
Endothelial cell：endothelin…
Hormone
Chemical messengers produced by a
variety of specialized secretory cells
Chemical signals secreted into the
blood stream that act on distant
tissues, usually in a regulatory
fashion
Sources of Hormones
Hormone secretory cells
(found around human body)
 Endocrine glands
 Tissues or cells of endocrine function:
neurosecretory cells in hypothalamus,
hormone secretory cells/organ cells with
endocrine function in GI tract, kidney,
heart, lung, etc
Hormones involved in Hypothalamus-Pituitary axis and their function
Classification of Hormone





Amino acid derivatives: dopamine,
catecholamines, thyroid hormone(TH)
Small neuropeptides: gonadotropin-releasing
hormone(GnRH), thyrotropin-releasing
hormone(TRH), somatostatin, vasoprssin
Large proteins: insulin, luteinizing hormone(LH),
parathyroid hormone(PTH)
Steroid hormones: cortisol, estrogen
Vitamin derivatives: retinoid(VitA), vitamin D, a
variety of peptide growth factors
Synthesis, Storage and Release of
Hormones
Peptide hormones:
Neural or endocrine stimulation → transcription
from DNA → mRNA → peptide product →
posttranslational protein processing →
intracellular sorting, membrane integration →
storage or secretion.
Synthesis and Processing of Insulin
Synthesis, Storage and Release of
Hormones
Steroid hormone:
Synthesis of most steroid hormones is based
on modifications of the precursor and
cholesterol.
Multiple regulated enzymatic steps are
required for the synthesis of testosterone,
estradiol, cortisol and vitamin D .
Patterns of secretion
Hormone secretion is continuous(e.g.
thyroid hormone) or intermittent(e.g.
LH,FSH).
Biological rhythms ------ Circadian
Circadian means changes over the 24
hours of the day-night cycle and is best
shown for the pituitary-adrenal axis.
Plasma cortisol levels during a 24-hour period
Hormonal and follicular changes during
the normal menstrual cycle
The menstrual
cycle is the best
example of a
longer and more
complex (28-day)
biological rhythm.
Patterns of secretion
Clinical significance of recognising
rhythms of hormonal secretion:
1.
Testing the hormone concentration
2.
Hormonal replacement therapy
Patterns of secretion
Other regulatory factors
 Stress
 Sleep
 Feeding and fasting
Plasma Transport of Hormones
Hormone
Binding protein(s)
Thyroxine (T4)
Thyroxine-binding globulin (TBG)
Thyroxine-binding prealbumin (TBPA)
Albumin
Triiodothyronine (T3)
(less bound than T4)
Thyroxine-binding globulin (TBG)
Albumin
Testosterone, estradiol
Sex hormone-binding globulin (SHBG)
Insulin-like growth
factor-I (IGF-l)
IGF-binding proteins (mainly IGF-BP3)
Cortisol
Cortisol-binding globulin (CBG)
Hormones ,their receptors and pathways
Degradation of Hormones
Hormone transport and degradation
dictate the rapidity with which a hormonal
signal decays. Some hormonal signals are
evanescent (e.g.somatostatin), whereas
others are longer lived (e.g. TSH)
Most hormones are deactivated in live,
kidney or peripheral tissues. Thus it must
be noted that hepatic insufficiency or
renal insufficiency may result in prolonged
half life of some hormones
Functions of Hormones
Metabolism
organ function
growth
development
reproduction
Maintainance of homostasis of internal
enviroment
Feedback
Hypothalamus Pituitary-target gland axis
Hypothalamus Pituitary thyroid axis
Hypothalamus Pituitary adrenal axis
Hypothalamus Pituitary gonad axis
Endocrine and metabolism
Insulin vs glucose
PTH vs calcium
ADH vs plasma osmotic pressure
Hypothalamus Pituitary thyroid axis
Hypothalamus Pituitary adrenals axis
Hypothalamus Pituitary gonad axis
Insulin and blood glucose
Classification of endocrine disease
1. primary endocrine disorder
2. secondary to other disease
3. ectopic endocrine disorder
4. due to receptor dysfunction
5. heredity abnormal hormones
6. iatrogenic
Diagnosis
Clinical picture
history、symptom、sign
Lab findings
evidence of metabolic disturbance:
target tissue or/and organs function
evidence of inappropriate hormone：
hormones or their metabolite of
endocrine function test
immunology
Diagnosis
Imageology
X ray，CT，B ultrasound ，isotope
Histology and cytology
Cytogenetics
Typical features in endocrine disease
dwarfism
acromegaly
gigantism
Typical features in endocrine disease
Addison disease
hyperthyroidism
Cushing syndrome
Cretinism
Principal of diagnosis



functional Cushing’s symdrome
pathology adrenal hyperplasia
etiology
pituitary microadenoma
complications diabetes
diabetic nephropathy
concurrent disease hypertension
cataract
prophylaxis and treatment
prophylaxis：
endemic goiter
Iodine deficiencyiodine
replacement
Treatment：
hyperfunctioning
medicine、surgery、radiation
hypofunction
hormones replacement and transplantation
symptomatic and supporting therapy
Thank you for your attention!