normal pituitary magnetic resonance scan - home - ksu 正常垂体磁共振扫描-家居-堪萨斯州立大学

Hypothalamic pituitary axis,Robert Schmidli MB ChB, MRCP, FRACP, PhDConsultant endocrinologist,.au,Lecture outline,Case historyStructure and functionPituitary and hypothalamic hormonesDisorders of pituitary functionDiscussion case history,Case history,Mrs “R” 64 year-old lady,Attended diabetes clinic for routine review blood glucose 1997 incidental findingDaughter has type 1 diabetesOn oral hypoglycaemic agentsDiabetes well controlledHypertension,Assessment - 1998,Unusual facial appearance, deep nasal voiceDenied any other problemsSinus problemsEnlarged noseThickened skinDeep voice“Spade-like” handsVisual fields normal,Investigations,Growth hormone:59.3 mU/l 25Insulin-like growth factor-1(IGF-1):862 g/l 98-390Skull X-ray:erosion of dorsum sellaeHand X-ray:prominent tufts of the terminal phalanges,Magnetic resonance scan pituitary,Tumour,Pituitary stalk,Optic chiasm,Normal pituitaryMagnetic resonance scan,Pituitary,Sphenoid sinus,Pituitary stalk,Optic chiasm,Internal carotid,Lateral ventricle,Progress,Trans-sphenoidal surgerySweating improvedFace less puffyHypertensive: 184/104 later improvedGH 2.1IGF-1 302Able to stop oral hypoglycaemicsRemains free of symptoms (2006),Structure and function,The hypothalamus and pituitary,Higher centres,Autonomic function,Environmental cues,Endocrine feedback,HYPOTHALAMUS,PITUITARY,ENDOCRINE GLANDS,The Pituitary Gland,Small outgrowth of the forebrainSize of half a peaTwo functional partsAdenohypophysis (anterior pituitary)Rathkes pouch ectoderm above mouthNeurohypophysis (posterior pituitary)HypothalamusMove together during development,Blood and nerve supply,HypothalamusHypothalamic neurons release hormones directly into capillary plexus Anterior pituitaryBlood supply from median eminence of hypothalamus portal systemHormones from hypothalamus to pituitarySympathetic/parasympathetic nervesPosterior pituitarySupraoptic and paraventricular nuclei in hypothalamus,Structure of pituitary,Anterior pituitary,Posterior pituitary,Pituitary stalk,Portal vessels,Hypothalamic releasing hormones,Function of anterior pituitary gland,Removal results in atrophy and hormone deficiency of:ThyroidAdrenal cortexGonadsGrowth hormoneDeath may occur due to cortisol deficiency,Regulation of secretion,Higher centres,Hypothalamus,Pituitary,Hormone,Pituitary hormone,Releasing hormone,Long feedback Loopeg. Thyroxine, Cortisol,Short feedback Loopeg. LH, ACTH, GH,Target gland,Pituitary and hypothalamic releasing hormones,Posterior pituitary hormones,Vasopressin/Antidiuretic hormone (ADH)Produced by supraoptic nucleusConserves water - concentrates urine Water reabsorption by collecting tubuleDeficiency: diabetes insipidusExtreme thirst and polyuria plasma sodium and osmolalityExcess: inappropriate ADH “water intoxication”OxytocinMilk let-down,Anterior pituitary hormones,TSH:Thyroid stimulating hormoneACTH:Adrenocorticotrophic hormoneLH:Luteinising hormoneFSH:Follicle stimulating hormoneProlactinGH:Growth hormone,Thyrotrophin (TSH),Stimulates:thyroxine synthesisthyroid growthRegulation:TRH: stimulates releaseInhibited by thyroid hormones (T3, T4) feedback inhibitionActs via cAMP,Corticotrophin (ACTH),Released as prohormone: pro-opio-melanocortinMaintenance of adrenal cortical functionCortisolOther adrenocortical hormones (eg androgens)Control of ACTH secretion:CRFCortisol (feedback inhibition),Luteinising hormone: LH,Males: Leydig/interstitial cells testosteroneInhibited by testosteroneFemales:Interstitial cells estrogen, androgens, progestinsInhibited by estrogen,Follicle stimulating hormone: FSH,Regulation of gametogenesisMales:Sertoli cells development of spermatozoaInhibited by inhibinFemales:Granulosa cell of ovarian follicleInhibition complexWorks synergistically with LH,Prolactin,Secreted by lactotrophs of ant. PituitaryLactation: only known functionInhibits reproductive hormone secretionRelease inhibited by dopamine “prolactin inhibitory factor”Animals: osmoregulation, growthStalk transection prolactin,Growth hormone,Promotes growth: skeleton, muscles, visceraEffects mediated by somatomedinsReleased at night during growthVariety of metabolic effectsAnabolic, positive nitrogen balanceAnti-insulinStimulated by GHRH, stress, exerciseInhibited by somatostatin,Pituitary releasing hormones,Small peptidesActive at relative high concentrationsRapidly degradedLow concentration in peripheral circulationSpecial circulation allows high concentrations to reach targets,Pituitary releasing hormones,CRH:Corticotrophin releasing hormone (ACTH)TRH:Thyrotrophin releasing hormoneGHRH:GH releasing hormoneSomatostatin:GH inhibitionGnRH:Gonadotrophin (LH, FSH) releasing hormoneDopamine:Prolactin inhibitionVasopressin:ACTH release,Pituitary disorders,Hyperfunction,Usually caused by tumourProlactin: commonestGalactorrhoeaInfertilityADH: syndrome of inappropriate ADH secretion (nonpituitary causes)Acromegaly: growth hormoneCushings syndrome: ACTHMay also have adrenal or ectopic sourceTSH, LH, FSH, oxytocin: exceedingly rare,Hypofunction,Any hormone except prolactin, oxytocin (no recognised clinical syndrome)Range from mild (GH) to lethal (ACTH)Causes: tumour, trauma, infection, developmental etcMay be combined: panhypopituitarism,Acromegaly,Don Fermin y Urieta (1870-1913)“The Giant of Aragorn”229 cm tall,Acromegaly,Growth hormone excess in adultsChildren: gigantismOften not recognised for 10-20 yearsLinear bone growth not possible after fusion of epiphyses,Growth hormone release,06:00,06:00,24:00,18:00,12:00,Normal,Acromegaly,Clinical features,Increase in ring, shoe, glove, hat sizeIncrease in size of nose, lips,