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Skeletal muscle
Adipose Tissue
Liver
Bone
Diurnal Rhythm of GH
0
+100%
-100%
VARIATION
12 midnight 6am 12 noon 6pm 12 midn
GH - Secreción Pulsatil
l ________ Regular Fed Day ______Fasting Day l Pulsos son regulados por GHRH, Ghrelina y Somatostatina l Feedback por IGF-l, Leptina y la GH misma l Hartman ML, Veldhuis JD, Thorner MO. Hormone Research 40: 37-47 1993.
EJERCICIO SUEÑO
HIPOGLICEMIA
HIPOTALAMO
PITUITARIA
HIGADO
BLOQUEA LA ENTRADA DE GLUCOSA EN
EL TEJIDO ADIPOSO
ESTIMULA LA SINTESIS DE PROTEINAS
AUMENTA LA GLUCONEOGENESIS
GHRH SOMATOSTATINA
GH
IGF´s
(-) (+)
(-) (-)
(+)
GHRELINA (+)
LOS AZUCARES PASAN MAS
RAPIDAMENTE A LA CIRCULACION
QUE LAS PROTEINAS
Blood concentrations of ghrelin are lowest shortly after consumption of a meal, then rise during the fast just prior to the next meal. The figure shows this pattern based on assays of plasma ghrelin in 10 humans during the course of a day.
Hipotálamo VentroMedial
Núcleo Para Ventricular Área Hipotalámica Lateral
Núcleo Tracto Solitario
Núcleo Motor Dorsal del Nervio Vago
Locus Coeruleus
GHRELINA PRODUCIDA EN
ESTOMAGO, CEREBRO (HIPOTALAMO), INTESTINO Y PANCREAS VIA OREXIGENICA (ESTIMULADORA DEL APETITO) DEL NUCLEO ARCUATO
Neuropeptide Y (NPY) and Agouti-Related Protein (AGRP) LEPTINA
PRODUCIDA EN TEJIDO ADIPOSO VIA ANOREXIGENICA Pro-opiomelanocortina (POMC) y Cocaine- and Amphetamine Regulated Transcript (CART)
NUCLEO VENTROMEDIAL = CENTRO DE LA SACIEDAD
Insulin
5HT
Receptors for ghrelin have been found on NPY neurones in the hypothalamic arcuate nucleus, a major brain area involved in the control of appetite. The NPY neurones are potent stimulators of appetite and upon activation by ghrelin they inhibit the POMC neurones by releasing the inhibitory neurotransmitter GABA which inhibits the release of alpha MSH, an inhibitor of appetite. Ghrelin also activates the release of AgRP which is an antagonist of the alpha MSH receptors MC3 and MC4, blocking alpha MSH from activating its receptor and inhibiting appetite
α2-‐AR, α2-‐adrenergic receptor; β3-‐AR, β3-‐adrenergic receptor; AC, adenyl cyclase; ACh, acetylcholine; cAMP, cyclic AMP; Ca++, calcium ions; DAG, diacylglycerol; DMV, dorsal motor nucleus of the vagus nerve; FFA, free faBy acids; Gi, inhibitory G protein; GK, glucokinase; GLP-‐1, glucagon-‐like pepFde 1; GLP-‐1R, GLP-‐1 receptor; Glu-‐6-‐PO4, glucose-‐6-‐phosphate; Glut4, glucose transporter 4; + HSL, hormone-‐sensiFve lipase; IML, intermediolateral cell column; IP3, inositol triphosphate; K , potassium ions; KATP, ATP-‐dependent potassium channel; LC, locus coeruleus; LHA, lateral hypothalamic area; LPL, lipoprotein lipase; M1 and M3, muscarinic receptors; MARCKS, myristoylated alanine-‐rich protein kinase C substrate; Na+, sodium ions; NE, norepinephrine; PIP2, phosphaFdylinositol pyrophosphate; PKA, protein kinase A; PKC, protein kinase C; PLC, phospholipase C; PVN, paraventricular nucleus; SNS, sympatheFc nervous system; SS5R, somatostaFn receptor type 5; SUR, sufonylurea receptor; TG, triglyceride; VCa, voltage-‐gated calcium channel; VMH, ventromedial hypothalamus.
β3-Adrenergic Receptor
White Adipose Tissue
Response to Leptin therapy in Congenital leptin deficiency
NPY CRH
POMC
GC
ACTH
HIPOTALAMO
HIPOFISIS
ADRENALES
PROTEOLISIS EN TEJIDOS PERIFERICOS (SUMINISTRO
DE SUSTRATOS GLUCONEOGENICOS)
AUMENTO DE LIPOLISIS ADIPOCITARIA, PERO EN
FORMA CRONICA
INHIBICION DE CAPTACION DE GLUCOSA
POR TEJIDOS PERIFERICOS
AUMENTO DE GLUCONEOGENESIS
GLUCAGON
OB INSULINA
ADIPOCITO
LEPTINA
Ob-R
STAT3 ENDOCANABINOIDES
Signal transducer & activator of transcription
ANANDAMIDE 2-ARACHIDONYL GLYCEROL
TRH SRIF GHRH
GH PRL
IGF
HIPOTALAMO
HIPOFISIS
HIGADO
TEJIDOS PERIFERICOS
?
TESTOSTRONA CORTISOL
AG. GRASOS
GHS
GH ↑ metabolismo de lípidos ↑ energía
R GH
Adipocito
Trigliceridos
Ac. grasos
Acetatos CoA
Acetil CoA
Ciclo de
Krebs
GH ↓ metabolismo de CHO
Glut
Glucosa Glucosa
Glicogeno
Ac. Grasos
Acetatos CoA
Acetil CoA
CO2 + ácido láctico + Energía
Ac. Piruvico
Glucosa 6-PO4
Glucosa 6-PO4
Ciclo de
Krebs
MAS IMPORTANTE
ESTE SUMINISTRO
Focal Adhesion Kinase cytoskeletal reorganization, cell migration, chemotaxis,
mitogenesis, and/or prevention of apoptosis and gene
transcription.
Suppressor of cytokine signalling
Gamma-interferon- activated sequence
(GAS)-like element (GLE)
GH [A]
[C]
JAK2 fosforilación
[B] Unión de GH ⇒ dimeriza-ción; JAK2/ TYK2 activación
[D]
TYK2 y fosforilación por JAK2
= receptor monomero = TYK2 = JAK
GH GH
P
GH
GH GH GH GH
P
P P
JAK = Janus-associated kinase TYK2 = Tyrosine kinase 2
[E] EFECTOS IGF-1 release (liver) lipolysis (adipose) a.a. uptake (muscle)
P P
[D] translocación
= receptor monomero = TYK2 = JAK
= STAT
[A]
P
P
P
STAT
GH
[B]
P
P
P
STAT
GH
P
P
P
STAT
GH
P
P
P
GH
[C] dimer formation
P P
Stat dimero
STAT STAT
STAT STAT
STAT STAT
STAT STAT
STAT
P P P
P P
P
P
P
STAT P STAT P STAT P STAT P
STAT P STAT P
Signal transducer & activator of transcription
NUCLEO
Interferon Gamma Activated Sequence
importin a/b and RanGDP
calcium release-activated Ca2+
INYECCION DE ARG
Mide la capacidad de la pituitaria para secretar GH
Inyecciones de GH tres veces por semana Tratmiento con GH
No hay aumento de GH en respuesta a la hipoglicemia
Panhipopituitarismo: deficiencia de las hormonas de la hipofisis anterior
Miércoles 6 de Febrero, 2007
PROTEINAS CORPORALES
AMINOACIDOS
Degradación Proteica (20-35 g/día de N)
CRECIMIENTO Reutilización para nueva síntesis proteica (15-25 g/día de N)
Alimentación AA con equilibrio ENERG/PROT CATABOLISMO
(5-7 g/día N)
" ASOCIADO A PROTEINA G
" ESTIMULA LA FORMACION DE AMPc
" EXPRESADO EN LA PITUITARIA
AMPc
AMP
ATP
Ca++/CaM
PK P GH
GHRH
SRIF
R
R
MEMBRANA
Higado
IGF-1 huesos y músculo
SRIF
↓cAMP
JAK
Células Somatotrofas secretan GH
HIPOTALAMO
GHRH
↑cAMP
Area Periventricular Arriba del quiasma optico
GH unida a GHBP
Nucleo Arcuato
Feedback negativo
Feedback negativo
Feedback positivo
⊕
Receptor β1 or β2
ATP AMPc
Gs β γ
αs β γ
Adenilato cyclasa
inactiva
γ β
GTP
Adenilato ciclasa Activa
Adenilato cyclasa inactiva
α2 receptor
Gi
γ αi
GTP αs
GTP
αi
GHRH SRIF
CELULAS SIMATOTROFAS
GTP
β β
CREB = Cyclic AMP Responsive Element Binding protein
Proteina Kinasa A Activa
É
GH secretion
ATP AMP ciclico
Adenilato ciclasa
ACTIVA
Aumento de la transcripción del gen de la GH
Sintesis de GH
NUCLEO
HO CREB ATP
PO CREB
PO OP OP PO
OP PO
L-‐692,429
FIG. 3. Fluorescent raFo imaging showing the effect of L-‐692,429 on cytoplasmic free Ca21 in a rat somatotroph. Images of a somatotroph at 340 nm and 380 nm are shown as a funcFon of Fme aUer addiFon of L-‐692,429. The concentraFon of L-‐692,429 selected was 33-‐fold theEC50 for GH release, and the free intracellular Ca21 increased from approximately 100 to 780 nM (29). [Reprinted with permission from R. G. Smith et al.: Science 260:1640–1643 (29). © 1993 American AssociaFon for the Advancement of Science.]
Spiroindanos
MK-‐0677
• Su receptor actúa vía proteina-‐G, acFvando a la PLC
Pituitary specific transcription factor 1
Potential mechanisms mediating the antitumorigenic actions of GHRH antagonists (GHRH-Ant).
Kineman R D PNAS 2000;97:532-534
©2000 by The National Academy of Sciences
(phosphatase and tensin homolog deleted on chromosome 10)
eukaryotic translation initiation factor 4E binding protein
eukaryotic translation initiation factor 4E
Phosphatase and tensin homologue
Target Of Rapamycin
PI3K
• EL DOMINIO KINASA DEL RECEPTOR (IGF1-R) COMPARTE 84% DE HOMOLOGIA CON EL DE LA INSULINA
• EL IGF-1 SE PUEDE UNIR AL RECEPTOR DE LA INSULINA Y VICEVERSA (PERO CON MUCHO MENOS AFINIDAD)
Figure 3 Potential insulin/IGF-1 signaling pathways in the pancreatic [beta]-cell
Biochemical Society Transactions Biochem. Soc. Trans. (2002) 30, 317-322
sarco-endoplasmic reticulum calcium ATPase
hepatocyte nuclear factor
EXPRESION DE LOS RECEPTORES LA DENSIDAD DE LOS RECEPTORES AL IGF-I REVELA UN
PATRON ESPECIFICO DE LOS TEJIDOS A LO LARGO DEL DESARROLLO
BIOENSAYOS (IGF) " MEDIDA DE LA INCORPORACION DE SO4
35 EN EL CARTILAGO PELVICO DE POLLO CON SUERO
" DOSIFICACIONES DE LA BINDING PROTEIN DEL IGF-I
IGFBP-related proteins Acid Labile Subunit
IGFBP-1
EXTIENDE LA VIDA MEDIA DE LOS IGF´s
Platelet-derived Growth Factor
phosphoinositide-dependent protein kinase
Phosphoinositide-3-kinase
Serum and glucocorticoid-inducible kinase (SGK)
Fig.1. IGF signaling is sufficient and required for anterior development in Xenopus embryos. (A) Secondary head-like structure induced after microinjection of 400 pg IGF2 mRNA into one ventral blastomere at the 4-cell stage. cg, secondary cement gland; ey, ectopic eye. (B) Uninjected 3-day tadpole. (C) Embryo injected with 500 pg dominant negative IGF type 1 receptor (DNIGF) mRNA per animal blastomere at the 4-8 cell stage showing reduction of cement gland and eye structures. (From Pera et al. (2001) Dev. Cell)
Figura 6. IGF-I y "miogénesis" durante la hipertrofia compensatoria. Grandes cargas conllevan a la proliferación, diferenciación, y fusión de las células "satélite". La IGF-I se ha demostrado que estimula estos procesos miogénicos en los músculos esqueléticos. Se ha postulado que la IGF-I y/o la isoforma IGF-I factor de crecimiento mecánico sensible a la sobrecarga (mechano growth factor, MGF), es producida y liberada por las miofibras en respuesta a una carga mayor o estiramiento. La mayor concentración local de IGF-I (MGF) estimularía entonces los procesos miogénicos necesarios para dirigir la respuesta de la hipertrofia.