Pengantar Endokrinologi

Pengantar Pengantar EndokrinologiEndokrinologi

Pengantar Pengantar EndokrinologiEndokrinologi

Pugud SamodroPugud SamodroBag/SMF Ilmu Penyakit Dalam FKIK Unsoed/RSUD Bag/SMF Ilmu Penyakit Dalam FKIK Unsoed/RSUD

Prof Margono SoekarjoProf Margono SoekarjoPurwokertoPurwokerto

• ENDOKRINOLOGICab. Ilmu kedokteran yang pelajari fungsi kelenjar buntu dalam keadaan fisiologis dan patologis.

• HORMONZat yang dihasilkan oleh kelenjar buntu yang dapat pengaruhi sel/jaringan/organ tubuh melalui reseptor khusus

• RESEPTOR KHUSUSReseptor yang terletak pada sel yang jadi sasaran (membran sel/intra sel)

No cell lives in isolation Cells depend on signaling systems to

adapt to changing environmental conditions

Why are signals important?

• Controlling e.g., metabolism, differentiation, cell division

• Development of immunity and Eradication of pathogens

• Prevent excessive growth• Elimination of superfluous cells by

inducing cell death

Components of SignallingWhat can be the Signal? External message to the cell

• Peptides / Proteins- Growth Factors• Amino acid derivatives - epinephrine,

histamine• Other small biomolecules - ATP• Steroids, prostaglandins• Gases - Nitric Oxide (NO)• Photons• Damaged DNA• Odorants, tastants

Signal = LigandLigand- A molecule that binds to a specific site on another molecule, usually a protein, ie receptor

modes of cell-cell signaling

Direct • cell-cell or cell-matrix

Secreted molecules. • Endocrine signaling. The signaling molecules are

hormones secreted by endocrine cells and carried through the circulation system to act on target cells at distant body sites.

• Paracrine signaling. The signaling molecules released by one cell act on neighboring target cells (neurotransmitters).

• Autocrine signaling. Cells respond to signaling molecules that they themselves produce (response of the immune system to foreign antigens and cancer cells).

Gap junction• Protein channels -

connexin• Direct flow to

neighbor– Electrical- ions

(charge)– Signal chemicals

Direct communication(Gap Junction & CAMs)

Contact dependent / Cell-Adhesion Molecules

•Need direct surface contact•Signal chemical

Means of cell to cell communication:

• Chemical : extra cellular signaling– Autocrine & Paracrine: local signaling– Endocrine system: distant, diffuse

target

• Electrical– Gap junction: local– Nervous system: fast, specific, distant

target

Autocrine & paracrine• Local

communication • Signal chemicals

diffuse to target• Example: Cytokines

– Autocrine–receptor on same cell

– Paracrine–neighboring cells

Long distance communication : hormones

• Signal Chemicals• Made in

endocrine cells• Transported via

blood• Receptors on

target cells

oct08 12

Long distance communication: neuronal

• Neurons– Electrical signal down axon– Signal molecule (neurotransmitter)

to target cell

Long distance communication : neurohormones

– Chemical and electrical signals down axon

– Hormone transported via blood to target

pembawa

Kelenjar

* globulin (>>)

* prealbumin * albumin

H H R

post reseptor

Generic Signal Transduction

• PENYAKIT ENDOKRIN Dapat terlihat jelas/ tertutup Mudah diobati bila diagnosis

tegak sebab terjadinya gangguan :

kelebihan atau kekurangan hormon terbentuknya hormon biologik inaktif

antibodi terhadap hormon gangguan reseptor sel (defect

reseptor/post reseptor) gangguan pada reseptor sel

blocking/antibodi terhadap reseptor yang bersifat simulasi

Efek berkurang : pabrik rusak pabrik membuat namun

kualitas menurun pembawanya kurang Reseptornya kurang Post reseptor kurang

Efek berlebih : produksi pabriknya berlebihan

Secara etiologik kelainan endokrin :1. Hipofungsi

- atrofi kelenjar/sebab umum, idiopatik- destruksi kelenjar (infeksi, trauma,

tumor)- kongenital

2. Hiperfungsi- hiperplasia- adenoma aktif- tumor ganas

SEKRESI HORMON

Hormon tidak keluar terus-menerus, ada pemicu :

1. Neuronal : catecholamine2. Biokimiawi : insulin terhadap glukosa3. Hormonal : respon terhadap releasing &

inhibiting hormon4. Kerusakan sel : tiroiditis5. Pengeluaran hormon secara :

- pulsatil : GnRH- siklik : cortisol