Nomad: Anterior Pituitary Physiology

04/07/2304/07/23 EndoPhysio AntPitParaEndoPhysio AntPitPara 11

ANTERIOR PITUITARY ANTERIOR PITUITARY GLAND GLAND

ByBy

Dr. M. Anthony David, MDDr. M. Anthony David, MD

Professor of PhysiologyProfessor of Physiology



PITUITARY GLANDPITUITARY GLAND Synonym: Synonym: Hypophysis CerebriHypophysis Cerebri.. Pituita = Mucus (Latin)Pituita = Mucus (Latin) So named by the Scientist So named by the Scientist GalenGalen Hypophysis Cerebri = Outgrowth Hypophysis Cerebri = Outgrowth

from the Cerebrum.from the Cerebrum. Has two important parts:Has two important parts:

Anterior Pituitary: Anterior Pituitary: AdenohypophysisAdenohypophysis Posterior Pituitary: Posterior Pituitary: NeurohypophysisNeurohypophysis


EMBRYOLOGY OF THE PITUITARYEMBRYOLOGY OF THE PITUITARY

Anterior Pituitary or Adenohypophysis:Anterior Pituitary or Adenohypophysis: Derived from an upward evagination of the Derived from an upward evagination of the

Rathke’s pouchRathke’s pouch.(Ectoderm).(Ectoderm) Posterior Pituitary or Neurohypophysis:Posterior Pituitary or Neurohypophysis:

Derived from a downward growth of the Derived from a downward growth of the InfundibulumInfundibulum from the Diencephalon, a from the Diencephalon, a structure of the structure of the NeurectodermNeurectoderm..


PITUITARY GLANDPITUITARY GLAND

DIMENSIONS:DIMENSIONS: 1 cm in diameter.1 cm in diameter. 0.5 to 1 gm in weight.0.5 to 1 gm in weight.

LOCATION:LOCATION: Sella turcicaSella turcica A bony cavity.A bony cavity.

DIVISIONS:DIVISIONS: Anterior LobeAnterior Lobe Posterior LobePosterior Lobe Pars IntermediaPars Intermedia


ADENOHYPOPHYSIS:ADENOHYPOPHYSIS:CLASSICAL CLASSIFICATION OF CLASSICAL CLASSIFICATION OF

CELLSCELLS CHROMOPHOBES:CHROMOPHOBES:

50% of the cells50% of the cells Agranular, quiescent & Non secretoryAgranular, quiescent & Non secretory

CHROMOPHILSCHROMOPHILS:: AcidophilsAcidophils: 35%: 35%

Secrete: Growth Hormone & ProlactinSecrete: Growth Hormone & Prolactin BasophilsBasophils: 15%: 15% Secrete: Secrete:

Glycoproteins : FSH, LH & TSHGlycoproteins : FSH, LH & TSH Polypeptides : ACTH & MSHPolypeptides : ACTH & MSH


MODERN CLASSIFICATIONMODERN CLASSIFICATION OF ADENOHYPOPHYSIAL CELLSOF ADENOHYPOPHYSIAL CELLS

SOMATOTROPHS:SOMATOTROPHS: Secrete Growth Secrete Growth

HormoneHormone MAMMOTROPHS:MAMMOTROPHS:

Secrete ProlactinSecrete Prolactin THYROTROPHS:THYROTROPHS:

Secrete TSHSecrete TSH

GONADOTROPHS:GONADOTROPHS: Are of two types:Are of two types:

FSH type: secrete FSH type: secrete FcHFcH

LH type: secrete LHLH type: secrete LH

CORTICOTROPHS CORTICOTROPHS ((ADRENOCORTICOADRENOCORTICOMELANOTROPHSMELANOTROPHS)) Secrete ACTH & Secrete ACTH &

MSHMSH


ADENOHYPOPHYSIAL HORMONESADENOHYPOPHYSIAL HORMONES

GROWTH HORMONEGROWTH HORMONE: SOMATOTROPIN: SOMATOTROPIN THYROTROPINTHYROTROPIN: THYROID STIMULATING : THYROID STIMULATING

HORMONE (HORMONE (TSHTSH)) ADRENOCORTICOTROPIC HORMONE(ADRENOCORTICOTROPIC HORMONE(ACTHACTH)) GONADOTROPIC HORMONES:GONADOTROPIC HORMONES:

FOLLICLE STIMULATING HORMONE (FOLLICLE STIMULATING HORMONE (FSHFSH)) LUTEINISING HORMONE (LUTEINISING HORMONE (LHLH); Interstitial Cell ); Interstitial Cell

Stimulating Hormone (Stimulating Hormone (ICSHICSH)) PROLACTINPROLACTIN


Adenohypophysial Adenohypophysial Hormones:Hormones:

A A MnemonicMnemonic for you! for you! ““TThose hose GGiant iant GGonads onads PProlong the rolong the

AAction”ction” TT = Thyroid Stimulating Hormone (TSH) = Thyroid Stimulating Hormone (TSH) GG = Growth Hormone = Growth Hormone GG = Gonadotropins: FSH & LH = Gonadotropins: FSH & LH P P = Prolactin= Prolactin A A = Adreno Cortico Tropic Hormone (ACTH) = Adreno Cortico Tropic Hormone (ACTH)


GROWTH HORMONE: GROWTH HORMONE: FUNCTIONSFUNCTIONS

ON GROWTH:ON GROWTH: In Children ( As the epiphyses are In Children ( As the epiphyses are

unfused)unfused) Increased Chondrogenesis.Increased Chondrogenesis. Increased Linear Growth.( Both in Increased Linear Growth.( Both in

conjunction with Somatomedins)conjunction with Somatomedins) In Adults, where the epiphyses In Adults, where the epiphyses

have fused:have fused: Thickening of bones.Thickening of bones.


GROWTH HORMONE:FUNCTIONS ON GROWTH HORMONE:FUNCTIONS ON METABOLISMS: METABOLISMS:

PROTEINS: ”PROTEINS: ”AnabolismAnabolism”” Anabolic effect by:Anabolic effect by:

Amino acid transport into cellsAmino acid transport into cells m & t RNA activitym & t RNA activity Nitrogen, Calcium, Sodium & Nitrogen, Calcium, Sodium & Potassium in the cellsPotassium in the cells

Protein CatabolismProtein Catabolism


CARBOHYDRATES: “DIABETOGENIC”CARBOHYDRATES: “DIABETOGENIC” Hyperglycemia caused by:Hyperglycemia caused by:

Gluconeogenesis.Gluconeogenesis. Peripheral Utilisation of Glucose: “Anti-Peripheral Utilisation of Glucose: “Anti-

Insulin”Insulin” GlycolysisGlycolysis FFA causing FFA causing need for glycolysis need for glycolysis

FAT:FAT: Increased FFA: Used for energyIncreased FFA: Used for energy



ELECTROLYTES:ELECTROLYTES: Increased Calcium absorptionIncreased Calcium absorptionRetention of:Retention of:

SodiumSodiumPotassiumPotassiumChlorideChloride



SOMATOMEDINSSOMATOMEDINS

Are Intermediate compounds, Are Intermediate compounds, polypeptide growth factors.polypeptide growth factors.

They facilitate the functions of They facilitate the functions of Growth Hormone.Growth Hormone.

Growth Hormone will not be able to Growth Hormone will not be able to function in the absence of these function in the absence of these somatomedins.somatomedins.

The most important of the The most important of the somatomedins is Somatomedin C or somatomedins is Somatomedin C or IGF I.IGF I.


SOME SOMATOMEDINSSOME SOMATOMEDINS Sulfation Factor Nerve Growth Factor (NGF) Epidermal Growth factor (EGF) Ovarian Growth Factor (OGF) Fibroblast Growth Factor (FGF) Platelet Derived Growth Factor (PDGF) Insulin like Growth Factor I (IGF I or

Somatomedin C) Insulin like Growth Factor II (IGF II)


FACTORS INFLUENCING GROWTH HORMONE FACTORS INFLUENCING GROWTH HORMONE SECRETIONSECRETION

HYPOTHALAMIC FACTORS

FASTINGEXERCISE

DEEPSLEEP V

A.As l DOPA

GLUCAGONANDROGENSESTROGEN

PROSTAGLANDINS

GROWTH HORMONE SECRETION

STRESS:SURGERY

ANESTHESIAHEMORRHAGEEXCITEMENT

“COLD”

HYPERGLYCEMIA PROTEIN ANABOLISM FFA OXIDATION ENERGY


THYROTROPIN (TSH) FUNCTIONSFUNCTIONS::

Releases stored Releases stored TT33,T,T44

Facilitates:Facilitates: IodinationIodination CouplingCoupling Other stages ofOther stages of

Biosynthesis.Biosynthesis.

LEVELS:LEVELS: MidnightMidnight EveningEvening

REGULATIONREGULATION:: TRH TRH

(Hypothalamus)(Hypothalamus) Negative feedback:Negative feedback:

TT33, T, T44

Via TRHVia TRH


CORTICOTROPIN: ACTHCORTICOTROPIN: ACTH

ACTIONS:ACTIONS: ADRENAL:ADRENAL:

Hypertropy & Hypertropy & Hyperplasia of Hyperplasia of z.fasciculata & z.fasciculata & reticularisreticularis

VascularityVascularity Basal & Stress Basal & Stress

inducedinduced

Cortisol levels.Cortisol levels.

EXTRA ADRENAL:EXTRA ADRENAL: MelanocytesMelanocytes Adipokinetic effectAdipokinetic effect Circadian Rhythm.Circadian Rhythm.

REGULATION:REGULATION: CRF & -VE FeedbackCRF & -VE Feedback

LEVELS: CircadianLEVELS: Circadian 4 – 6 AM4 – 6 AM EveningEvening


PROLACTINPROLACTIN In Males?In Males?

Potentiates effect of ICSH ( Potentiates effect of ICSH ( IInterstitial nterstitial CCell ell SStimulating timulating HHormone )ormone )

In Females:In Females: Promotes Milk Production in Estrogen & Promotes Milk Production in Estrogen &

Progesterone primed Mammary tissues.Progesterone primed Mammary tissues. Baby’s suckling increases Prolactin secretion Baby’s suckling increases Prolactin secretion

by the by the Milk Ejection/Secretion ReflexMilk Ejection/Secretion Reflex


Inhibits Ovulation by:Inhibits Ovulation by: Secretion & effect of LHRH on Pituitary glandSecretion & effect of LHRH on Pituitary gland Action of FSH/LH on OvaryAction of FSH/LH on Ovary Lactational AmenorrheaLactational Amenorrhea

On the CNS:On the CNS: Maternal Instinct, protective Behaviour (Limbic Maternal Instinct, protective Behaviour (Limbic

System)System) Regulation:Regulation: PIH/DOPAMINE: Depresses Prolactin PIH/DOPAMINE: Depresses Prolactin

production.production.

PROLACTINPROLACTIN


GONADOTROPINSGONADOTROPINS

FSHFSH:: Early maturation & Nutrition of OvaEarly maturation & Nutrition of Ova Release of EstrogensRelease of Estrogens

LHLH:: Final Maturation of OvaFinal Maturation of Ova OvulationOvulation Corpus Luteum formation.Corpus Luteum formation. In Males: ICSH: In Males: ICSH: Production of Production of

Testosterone.Testosterone.


NOW FOR ACOFFEE!



GROWTHGROWTH Physiological Growth is defined as Physiological Growth is defined as an an

increase in the number and size increase in the number and size of cells with sequential changes of cells with sequential changes in maturationin maturation..

Growth is normal and physiological in Growth is normal and physiological in children and adolescentschildren and adolescents

It becomes It becomes pathologicalpathological in in Malignancies or Malignancies or CancersCancers..


HYPERTROPY & HYPERPLASIAHYPERTROPY & HYPERPLASIA

HYPERTROPY:HYPERTROPY: Increase in the size Increase in the size

of the cells.of the cells.

HYPERPLASIA:HYPERPLASIA: Increase in the Increase in the

number of cells.number of cells.


FACTORS CONTROLLING FACTORS CONTROLLING GROWTHGROWTH

1. 1. GENETIC FACTORSGENETIC FACTORS:: Genes decide the tissue responsiveness Genes decide the tissue responsiveness

to GH.to GH.

2. 2. EXTRINSIC FACTORSEXTRINSIC FACTORS:: Diet/ Nutrition: PEM : Diet/ Nutrition: PEM :

KWASHIORKOR/MARASMUSKWASHIORKOR/MARASMUS

3. 3. ENDOCRINE FACTORS:ENDOCRINE FACTORS:


MARASMUSMARASMUS


ENDOCRINE FACTORS AFFECTING ENDOCRINE FACTORS AFFECTING GROWTHGROWTH

GROWTH HORMONEGROWTH HORMONE THYROXINTHYROXIN INSULININSULIN SEX HORMONES:SEX HORMONES:

ANDROGENSANDROGENS ESTROGENESTROGEN

GLUCOCORTICOIDSGLUCOCORTICOIDS GONADOCORTICOIDSGONADOCORTICOIDS


GENERAL GROWTH CURVEGENERAL GROWTH CURVE

X – AXIS: AGE IN YEARSX – AXIS: AGE IN YEARS Y – AXIS: GROWTH% SIZE AT 20 Y – AXIS: GROWTH% SIZE AT 20

YEARSYEARS HAS FOUR PHASES:HAS FOUR PHASES:

I : I : RAPIDRAPID GROWTH: 0 – 3 Years GROWTH: 0 – 3 Years II : II : SLOW SLOW PHASE: 3 – 13 YearsPHASE: 3 – 13 Years III: III: ACCELERATEDACCELERATED PHASE: 13 – 16 Years PHASE: 13 – 16 Years IV :IV : SLOW INCREASE SLOW INCREASE: 16 – 20 Years.: 16 – 20 Years.


GENERAL GROWTH GENERAL GROWTH CURVECURVE

0

20

40

60

80

100

120

0 2 4 6 8 10 12 14 16 18 20 22 AGE IN YEARS

% G

RO

WTH

AT 2

0yr

s


SPECIFIC GROWTH CURVESSPECIFIC GROWTH CURVES

NEURAL & HEAD CURVE:NEURAL & HEAD CURVE: Peaks by 3 to 6 years.Peaks by 3 to 6 years.

LYMPHOID CURVE:LYMPHOID CURVE: Peaks to Peaks to 200% 200% at 12 – 14 Years.at 12 – 14 Years.

SPLANCHNIC CURVE:SPLANCHNIC CURVE: Similar to the General growth Similar to the General growth

curve.curve. REPRODUCTIVE CURVE:REPRODUCTIVE CURVE:

Peaks at 13 – 16 years.Peaks at 13 – 16 years.


SPECIFIC GROWTH CURVES : SPECIFIC GROWTH CURVES : NEURAL & HEAD NEURAL & HEAD

0

20

40

60

80

100

120

2 4 6 8 10 12 14 16 18 20 22

AGE IN YEARS

% G

RO

WTH

AT 20yrs

.


SPECIFIC GROWTH CURVES: SPECIFIC GROWTH CURVES: LYMPHOID TISSUELYMPHOID TISSUE

0

50

100

150

200

250

2 4 6 8 10 12 14 16 18 20 22

AGE IN YEARS

%G

RO

WTH

AT 2

0 Y

rs


SPECIFIC GROWTH CURVES: SPECIFIC GROWTH CURVES: SPLANCHNIC TISSUESSPLANCHNIC TISSUES

0

20

40

60

80

100

120

0 2 4 6 8 10 12 14 16 18 20 22 AGE IN YEARS

% G

RO

WTH

AT 2

0yrs


SPECIFIC GROWTH CURVES: SPECIFIC GROWTH CURVES: RPRODUCTIVE TISSUESRPRODUCTIVE TISSUES

0

20

40

60

80

100

120

2 4 6 8 10 12 14 16 18 20 22

AGE IN YEARS

% G

RO

WTH

AT 20yrs

.


ANTERIOR PITUITARY: APPLIED ANTERIOR PITUITARY: APPLIED ASPECTSASPECTS

PAN HYPOPITUITARISM:PAN HYPOPITUITARISM: Simmond’s: Sheehan’s SyndromeSimmond’s: Sheehan’s Syndrome Frohlich’s Syndrome: Both Ant & Post Pit are Frohlich’s Syndrome: Both Ant & Post Pit are

deficient.(Dystropia Adiposa GenItalis)deficient.(Dystropia Adiposa GenItalis) HYPOSECRETION OF ANT PIT HORMONESHYPOSECRETION OF ANT PIT HORMONES

ADULTS: ADULTS: AcromicriaAcromicria INFANTS:INFANTS: Dwarfism Dwarfism: Laron type: : Laron type:

SomatomedinsSomatomedins Sexual Ateloitic: Intelligent DwarfsSexual Ateloitic: Intelligent Dwarfs


ANTERIOR PITUITARY: APPLIED ANTERIOR PITUITARY: APPLIED ASPECTSASPECTS

HYPERSECRETION OF HYPERSECRETION OF GH:GH: ADULTS: ACROMEGALYADULTS: ACROMEGALY INFANTS: GIGANTISMINFANTS: GIGANTISM


GIGANTISM

NORMAL


ACROMEGALY : ABCACROMEGALY : ABC

AA: ARTHROPATHY: Joint Disorders: ARTHROPATHY: Joint Disorders BB: BIG BOGGY HANDS: BIG BOGGY HANDS CC: CARPAL TUNNEL SYNDROME: CARPAL TUNNEL SYNDROME


DD: DIABETES MELLITUS: DIABETES MELLITUS EE: ENLARGED:: ENLARGED:

TONGUETONGUE HEART: CARDIOMEGALYHEART: CARDIOMEGALY THROATTHROAT

FF: FIELD DEFECT OF VISION: : FIELD DEFECT OF VISION: Bitemporal HemianopiaBitemporal Hemianopia

ACROMEGALY : DEFACROMEGALY : DEF


GG: GYNECOMASTIA, GALACTORRHEA & : GYNECOMASTIA, GALACTORRHEA & GREASY SKINGREASY SKIN

HH: HYPERTENSION: 20 – 50% CASES: HYPERTENSION: 20 – 50% CASES II: INCREASING SIZE OF:: INCREASING SIZE OF:

SHOESSHOES HATSHATS GLOVESGLOVES DENTURESDENTURES RINGSRINGS

ACROMEGALY : GHI ACROMEGALY : GHI



JJ: JAW : JAW ENLARGED: ENLARGED: PROGNATHISMPROGNATHISM

KK: KYPHOSIS: : KYPHOSIS: VERTEBRAL VERTEBRAL DEFORMITYDEFORMITY

ACROMEGALY: JKACROMEGALY: JK


REVIEWREVIEW Growth: Growth: an increase in the number and an increase in the number and

size of cells with sequential changes size of cells with sequential changes in maturationin maturation..

General & Specific Growth CurvesGeneral & Specific Growth Curves Applied Aspects:Applied Aspects:

Adults:Adults: AcromegalyAcromegaly AcromicriaAcromicria

Infants:Infants: GigantismGigantism Dwarfism: Intelligent!Dwarfism: Intelligent!


REVIEW: ACROMEGALYREVIEW: ACROMEGALY AA : ARTHROPATHY : ARTHROPATHY B B : BIG, BOGGY HANDS : BIG, BOGGY HANDS CC : CARPAL TUNNEL SYNDROME : CARPAL TUNNEL SYNDROME DD : DIABETES MELLITUS : DIABETES MELLITUS EE : ENLARGED: : ENLARGED:

TONGUETONGUE HEARTHEART THROATTHROAT

FF : FIELD DEFECT: Bitemporal : FIELD DEFECT: Bitemporal HemianopiaHemianopia


GG : GYNECOMASTIA, GALACTORRHEA & : GYNECOMASTIA, GALACTORRHEA & GREASY SKINGREASY SKIN

HH : HYPERTENSION : HYPERTENSION II : INCREASED SIZES OF : INCREASED SIZES OF

HATSHATS SHOESSHOES GLOVESGLOVES RINGSRINGS DENTURESDENTURES

JJ : JAW ENLARGED: PROGNATHISM : JAW ENLARGED: PROGNATHISM KK : KYPHOSIS : KYPHOSIS

REVIEW: ACROMEGALYREVIEW: ACROMEGALY


THANK YOU

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Nomad: Anterior Pituitary Physiology

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