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Introduction to endocrinology. Department of endocrinology and metabolism. Homeostasis .  Cells (pancreas) Insulin Blood glucose. liver, muscle, adipose tissue, et al. insulin receptor. meal. Time(min). The endocrine system. Endocrine glands APUD cells

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Introduction to endocrinology

Introduction to endocrinology

Department of endocrinology and metabolism


Homeostasis
Homeostasis

 Cells (pancreas)

Insulin

Blood glucose

liver, muscle, adipose tissue, et al

insulin receptor

meal

Time(min)


The endocrine system
The endocrine system

Endocrine glands

APUD cells

cells not belong to endocrine glands

Hormone

Regulate specific function

Receptor (target organs )


The endocrine system1
The endocrine system

Endocrine glands

APUD cells

cells not belong to endocrine glands

Hormone

Regulate specific function

Receptor (target organs )



Synthesis and degradation
Synthesis and Degradation

Hormone synthesis and degradation employs the same machinery used to produce, modify or degrade these compounds.

Hormone release

In many cases, hormones are released by the endocrine gland in a less active or inactive form,as prohormone.


Hormone transport
Hormone transport

  • Hormones circulate both free and bound to plasma proteins.

    eg. FT4VsTT4

    TT4 = FT4 + FT4combine to TG


freehormone

  • Is the fraction available for binding to receptors and therefore represents the active hormone.

  • Dictates the magnitude of feedback inhibition that controls hormone release.

  • Is the fraction that is cleared from the circulation .

  • Correlates best with clinical states of hormone excess and deficiency.


Hormone combined to plasma protein
HORMONE -combined to plasma protein

  • The binding of hormones to plasma proteins is through noncovalent interactions and tends to increase the half life of the hormone in the circulation.


The endocrine system2
The endocrine system

Endocrine glands

APUD cells

cells not belong to endocrine glands

Hormone

Regulate specific function

Receptor (target organs )


Mechanism of hormone action receptor
Mechanism of hormone action RECEPTOR

  • The actions of hormone are mediated by binding of the hormone to receptor molecules.

  • Hormones are allosteric effectors that alter the conformation of the receptors to which they bind.

  • The receptors are cellular proteins that have bifunctional properties of both recognition and signal activation.


Receptor
RECEPTOR

1. Nuclear receptors

2. Cell surface receptors


Nuclear receptors
Nuclear receptors

  • Superfamily - Steroid hormone,

    Vitamin D, thyroid hormone, retinoids

  • Nuclear receptors are ligand-regulated transcription factors that control gene expression by binding to target genes usually in the region near their promoters.


Nuclear receptors1
Nuclear receptors

  • Nuclear receptor superfamily have generally similar structures and functions, but there are subclasses that differ in the details of their actions - especially in their interaction with other proteins - and function in the unliganded state.


Receptor1
RECEPTOR

2. Cell surface receptors

a)Seven-transmembrane domain

b)Single-transmembrane domain

  • Growth factor receptor

  • Cytokine receptor

  • Guanyl cyclase-linked receptors


Catecholamine

ACTH

Glucagon

TSH

LH

PTH

Coupled to the “G proteins.”

Effectors: adenylyl cyclase and phospholipase C

Regulate the production of second messenger, cAMP



Growth hormone

Cytokine

interferons



Regulation of th e endocrine system
Regulation of the endocrine system

synthesis secretion transport degradation

Hormone

Quantity

Activity

Receptor (target organs )


Neuro-system

Endocrine system

Immune system


spontaneous rhythms

pulsatile

ultradian(< 24h) circadian (24h) infradian (> 24h)

CNS input

Immunal input

Other input

hypothalamus

releasing hormone

pituitary

tropic hormone

thyroid

adrenal cortex ovaries

Peripheral glands

hormone

Hormone-transport protein

receptor

Cascade

Target cell

Target cell

effect


Blood flow of kidney-input

renin

angiotensin

Aldosterone

ACTH

Urine K+ excretion

Serum K+


Disorders of the endocrine system
Disorders of the endocrine system

  • Excess of hormone

  • Deficiency of hormone

  • Resistance to hormone

  • Administration of exogenous hormone or medication


Approach to the patient with endocrine disease
Approach to the patient with endocrine disease

  • History & physical examination

  • Laboratory studies

  • Screening for endocrine diseases

  • Function diagnosis

  • Pathology diagnosis

  • Etiology adiagnosis


History physical examination

Amenorrhea or oligomenorrhea

Anemia

Anorexia

Conspitation

Depression

hair change

Hypothermia

Lipido change

Polynuria

Skin changes

Weakness and fatigue

Weight gain

Weight loss

Nervousness

Diarrhea

History & physical examination


Laboratory studies
Laboratory studies

  • Laboratory evaluations are critical both for making and confirming endocrine diagnose.


Laboratory studies1
Laboratory studies

  • Measure the level of hormone

total vs. free

Plasma vs. urine

  • The effect of hormone

  • The sequelae of the process


spontaneous rhythms

pulsatile

ultradian(< 24h) circadian (24h) infradian (> 24h)

CNS input

Immunal input

Other input

hypothalamus

releasing hormone

pituitary

tropic hormone

thyroid

adrenal cortex ovaries

Peripheral glands

hormone

Hormone-transport protein

receptor

Cascade

Target cell

Target cell

effect


Laboratory studies2
Laboratory studies

  • Basal level

  • Stimulation test

  • Inhibitory test

  • Imaging studies

  • Biopsy procedures


spontaneous rhythms

pulsatile

ultradian(< 24h) circadian (24h) infradian (> 24h)

CNS input

Immunal input

Other input

hypothalamus

releasing hormone

pituitary

tropic hormone

thyroid

adrenal cortex ovaries

Peripheral glands

hormone

Hormone-transport protein

receptor

Cascade

Target cell

Target cell

effect


spontaneous rhythms

CNS input

Immunal input

Other input

hypothalamus

Diurnal rhythms

disappear

CRH

pituitary

ACTH

Glucocorticoid-secreting adrenal adenomas

Low dose Dex test

large dose Dex test

glucocorticoid

receptor

Cascade

Target cell

Target cell

effect


Diagnosis:

1.Urine K+ excretion

Blood flow of kidney-input

Serum K+

S K+ <3.5mM, urine K+ excretion>30mM/24h

renin

S K+ <3.0mM, urine K+ excretion>25mM/24h

angiotensin

Serum K+

2.Aldosterone 

Serum, urine excretion

Aldosterone

ACTH

Urine K+ excretion

basal

3.renin 

stimulated

Serum K+


Clinical interpretation of lab tests
Clinical interpretation of lab tests

  • Any results must be interpreted in light of clinical knowledge of the patients

  • Basal levels of hormones or peripheral effects of hormones must be interpreted in light of the way the hormone is released and controlled.

  • Hormone levels must in many cases be interpreted conjuctionally (PTH vs. Ca, Renin vs. aldosterone)


Clinical interpretation of lab tests1
Clinical interpretation of lab tests

  • Occasionally, urinary measurements are superior to plasma tests for assaying the integrated release of hormone.

  • Provocative tests are sometime necessary.

  • Imaging studies may help with the diagnosis,specially with respect to the source of hormone hypersecretion.


Screening is important for some endocrine diseases
Screening is important for some endocrine diseases

  • Hypertension

  • Hypothyroidism

  • Diabetes


Approach to the patient with endocrine disease1
Approach to the patient with endocrine disease

  • History & physical examination

  • Laboratory studies

  • Screening for endocrine diseases

  • Function diagnosis

  • Pathology diagnosis

  • Etiology adiagnosis

  • immunologic examination

  • genetic examination

  • Chemical examination


HRT

etiology


Treatment of endocrine diseases
Treatment of endocrine diseases

For hormone Deficiencystates:

  • Hormones available

  • Hypothyroidism- thyroxin

  • Adrenal insufficiency-hydrocortisone

  • Menopause- estrogen- containing preparations

  • Hormones unavailable

  • PTH: Vit D & Ca


Surgery

Radiation

drug

HRT

etiology


Treatment of endocrine diseases1
Treatment of endocrine diseases

For hormone Excessstates:

  • Treatment is ordinarily directed at the cause of the excess,usually a tumor or autoimmune condition.

  • Hormone production may also be blocked by pharmacological means.

  • In many cases, it’s necessary to control squeal of hormone excess by alternative means.


The endocrine system3
The endocrine system

Endocrine glands

APUD cells

cells not belong to endocrine glands

Hormone

Regulate specific function

Receptor (target organs )


Disorders of the endocrine system1
Disorders of the endocrine system

  • Excess of hormone

  • Deficiency of hormone

  • Resistance to hormone

  • Administration of exogenous hormone or medication


Approach to the patient with endocrine disease2
Approach to the patient with endocrine disease

  • History & physical examination

  • Laboratory studies

  • Screening for endocrine diseases

  • Function diagnosis

  • Pathology diagnosis

  • Etiology adiagnosis

  • immunologic examination

  • genetic examination

  • Chemical examination


Surgery

Radiation

drug



Precipitating factors:

Infection, diet,surgery,trauma,pregnancy

DKA

Insulin-antagonistic hormone

ID

IR

Utilization is reduced

hyperglycemia

Mobilization of energy from lipid and protein

Osmotic diuresis

Ketone production

polyuria

Ketone accumulation

Pletion of intravascular volume

acidosis

Disturbance of electrocytes


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