Endocrine extras Flashcards
(47 cards)
Hormone classes (by chem nature) Tyrosine derived? Peptide? Proteins? Steroids?
Tyr - NE, epi, DA
Peptides - Hypothalamic, also Growth Hormone
Protein - Insulin, (GH?), PRL
Steroids - Gluco, Mineralo, Sex Steroids (HAVE LONGER HALF LIVES IN BLOOD, BUT NOT STORED IN CELL)
G protein mechs, and the Hypothalamic peptides that use them:
Gs –> incr cAMP (TRH, CRH, GHRH)
Gi –> drops AC so drops cAMP and activates K+ channels (SST, PIH (DA))
Gq –> PKC –> IP3, DAG (GnRH GHRH)
Receptors for hormone classes For steroids? Who binds GPCR? Who binds cytokine? WHo binds EGF?
Steroids: enter nucleus and bind HRE –> gene transcription
Surface GPCR: Hypothalamic peptides (so not DA!)
Surface Cytokine: GH, prolactin (JAK/STAT - activation transcription)
Surface EGF family: insulin (binds and activates protein kinase)
Posterior and Anterior pituitary (anatomical relation to hypothalamus?)
PP is continuation of Hypo
AP is epithelial in original (from pharyngeal epithelium - Rathke’s pouch)
Effect of GH on insulin?
Counters action of insulin - i.e. it gets everything ready for growth rather than storage - increases availability of glucose ready for growth
BUT for GH to release IGF-1 you NEED NORMAL INSULIN LEVELS
Laron’s dwarfism vs African pygmies
Laron’s normal GH but bad receptors
Pygmies: normal GH but bad IGF-1 receptors
Tertiary, Secondary, Primary
Tertiary is Hypo, Secondary is Pit (BOTH CENTRAL)
Primary is target organ (PERIPHERAL)
Scant pubic hair?
Central adrenal insuff!
Order for loss of pit hormones
1) GH and LH/FSH
2) TSH/ACTH
3) finally PRL
reflects importance of each (except PRL)
ADH defic common in which tumors?
Common in metastatic tumors but NOT in pituitary adenomas
Made in adrenal cortex?
steroids! (gluco-, mineralo-, sex-)
has 3 zonas
Zona glomerulosa
outermost adrenal cortex makes aldosterone (a mineralo)
Zona fasciculata
middle of adrenal cortes makes cortisol (a gluco)
Zona reticularis
inner adrenal cortex
makes adrenal androgens
Made in adrenal medulla?
Epi and NE (both tyrosine derived) - the catecholamines
Made from chromaffin cells
Epi works on what adrenergic receptors?
a1 –> Gq –> IP3/DAG
a2 –> Gi/o –> decr AC and thus dec cAMP, & open K+
B1-3 –> incr cAMP
Permissive affect of cortisol …
Incr epi release and incr B-adrenergic activity (by producing and inserting B-receptors)
Sx unique to primary adrenal defic
vitiligo, pigmentation, HYPERkalemia
APS-1
autoimmune polyglandular syndrome
INVOLVING AUTOIMMUNE REGULATOR GENE
hypoPARATHYROIDism and mucocutaneous candida
both have adrenal defic (Addi.) and T1DM
ADPS-1
autoimmune polyglandular syndrome
HLA ASSOCIATED
hypoTHYROIDism (Hashimoto)
both have adrenal defic (Addi.) and T1DM
Cortisol levels for Adrenal insuff?
100 = primary (small adrenal glands on CT for autoimmune or metabolic, large on all others)
ACTH LOW or nl = Secondary (with path on pit MRI)
Primary aldosteronism (two types and who to screen)
1) Aldosterone producing ademoma (APA) 34% - SURG poss (likely if age 160/100 (severe) or RESISTANT (2 drugs), HTN under 20 y/o, adrenal incidentaloma, IF UNDER 40, HYPOkalemic) give aldost antagonists
2) Idiopathic hyperaldosteronism (IHA) 66% - give aldost antagonists WITH BP meds, IF OVER 40
3 parts of Ant Pit & functions?
1) pars distalis (makes and secretes hormone)
2) pars tuberalis (round the infundibulum)
3) pars intermedia (between distalis and pars nervosa of post pit) FOLLICLES HERE
Ant pit derived from?
RATHKE’S POUNCH oral/pharyngeal ectoderm (completely separates and wraps around stalk)
