1 of 29

Pituitary Physiology and Deficiencies

Ipsita Maity.

Department of Zoology

2 of 29

Pituitary

Pituitary

“Master” gland
Most of the pituitary hormones control other endocrine glands

3 of 29

Goals of Discussion

Review pituitary anatomy
Understand pituitary physiology
Discuss pituitary hormone deficiencies

4 of 29

Nomenclature

Pituitary

Greek

ptuo (to spit)

Latin

Pituita (mucus)

Mucus was produced by the brain and was excreted through the nose by the pituitary

5 of 29

Pituitary Development

Evagination of the stromodeal ectoderm from buccal cavity

Infundibulum, neural stalk and posterior lobe from diencephalon

Development 3^rd to the 15^th week gestation

6 of 29

Pituitary Anatomy �Gross

Sits in sella turcica
Surrounded by dura
Sphenoid

Lateral and inferior

Lateral

Cavernous sinus

Internal carotid artery
CN III, IV, VI, V1 and V2

7 of 29

Pituitary Anatomy�Gross

Symmetrical bean shaped

Brownish red

13 mm transverse
9 mm AP
6 mm height
Adult

0.4-0.9 grams
Larger in women
Larger in multiparous women
During pregnancy increases to 0.9-1 grams

8 of 29

Pituitary Anatomy�Microscopic

Anterior lobe

80% of gland
Brown color

Posterior lobe

Gray/brown color

9 of 29

Pituitary Anatomy�Microscopic

Anterior lobe 3 divisions

Pars distalis

Largest
Hormone producing cells

Pars intermedia

Poorly defined in the human

Pars tuberalis

Upward extension to the anterior lobe and attached to pituitary stalk

Posterior lobe

Pars nervosa

10 of 29

Pituitary Gland�Microscopic

Pars distalis

Pink acidophils

Growth hormone
Prolactin

Dark purple basophils

Corticotropin (ACTH)
Thyroid stimulating hormone (TSH)
Follicle stimulating hormone (FSH)
Luteinizing hormone (LH)

11 of 29

Pituitary�Portal System

Hypophyseal arteries

From carotid
Superior

80-90% to adenophysis

Inferior

Posterior pituitary

Posterior lobe

Rich nerve supply
Unmyelinated nerves

12 of 29

Goals of Discussion

Review pituitary anatomy
Understand pituitary physiology
Discuss pituitary hormone deficiencies

13 of 29

Hormones Of The Anterior Pituitary

6 main hormones secreted by the adenohypophysis:

Growth hormone

Somatotropin

Thyroid-stimulating hormone

Thyrotropin

Adrenocorticotropic hormone

Corticotropin

Prolactin
Follicle-stimulating hormone
Luteinizing hormone

14 of 29

Anterior pituitary

Hypothalamic Pituitary Target Hormone

product product organ product

CRH ACTH Adrenal Cortisol

cortex

TRH TSH Thyroid T4, T3

GHRH (+) GH Liver; IGF-I (systemic)

SRIH (-) Tissues IGF-I (local)

PRIH PRL Breast [Lactation]

(dopamine)

GnRH LH, Gonad Sex hormones

(LHRH) FSH

15 of 29

Hormone Structure Amino acids/Source

Polypeptide/proteins

ACTH Polypeptide 39 Corticotroph

GH Protein 191 Somatotroph

PRL Protein 199 Lactotroph

Glycoproteins

TSH Alpha* / TSH-beta 110 Thyrotroph

LH Alpha / LH-beta 115 Gonadotroph

FSH Alpha / FSH-beta 115 Gonadotroph

[hCG Alpha / beta-hCG] 147 [Placenta]

* 92 amino acids

16 of 29

HYPOTHALAMUS

POSTERIOR

PITUITARY

GHRH

(+)

SRIH

(-)

HYPOTHALAMIC-

PITUITARY

PORTAL SYSTEM

TISSUES

DIRECT

EFFECTS

INCR. [FFA]

INSULIN RESISTANCE

GH

(-)

IGF-I

GROWTH

GH_AXIS_

IGFBP-3

17 of 29

(+)

POSTERIOR

PITUITARY

(-)

CRH

HYPOTHALAMUS

HYPOTHALAMIC-

PITUITARY

PORTAL SYSTEM

ACTH

CORTISOL

ADRENAL Fasiculata

(-)

18 of 29

TRH

(+)

HYPOTHALAMUS

HYPOTHALAMIC-

PITUITARY

PORTAL SYSTEM

T4, T3 (T4 --> T3)

THYROID GLAND

TSH

POSTERIOR

PITUITARY

(-)

19 of 29

POSTERIOR

PITUITARY

PRL

BREAST

PRIH

(-)

HYPOTHALAMUS

(DOPAMINE)

20 of 29

POSTERIOR

PITUITARY

LH, FSH

SEX HORMONES, INHIBIN

GONAD

(-)

GnRH

(+)

HYPOTHALAMUS

HYPOTHALAMIC-

PITUITARY

PORTAL SYSTEM

(LHRH)

21 of 29

Posterior pituitary

Hypothalamic

source (cell body) Target Effect

ADH Collecting H₂O retention

duct

Oxytocin Breast Milk let down

Uterus Smooth muscle

Contraction

22 of 29

Differential Diagnosis�Hypopituitarism

Isolated hormone deficiencies

Acquired or congenital

Tumors

Pituitary adenomas
Pituitary apoplexy
Hypothalamic tumors
Metastatic carcinoma

Inflammatory

Granulomatous disease

Sarcoidosis, TB and syphilis

Eosinophilic granuloma
Lymphocytic hypophysitis

23 of 29

Differential Diagnosis�Hypopituitarism

Vascular disease

Sheehan’s postpartum necrosis
Carotid aneurysm

Destructive

Surgery
Radiation
Trauma

Infiltration

Hemochromatosis
Amyloidosis

24 of 29

Hypopituitary�Presentation

Growth hormone production

First hormone to be disrupted

Gonadotropin deficiency

Easily disrupted

Corticotropin

Less frequently affected

Thyrotropin

Rarely affected

Anti-diuretic hormone

Deficiency usually due to tumor
Craniopharyngioma

25 of 29

Hypopituitary�Presentation

Growth hormone deficiency

Children

Short stature

Adults

Non specific
Fine wrinkling around the face
Improved insulin sensitivity

26 of 29

Hypopituitary�Presentation

Gonadotropin deficiency

Women

Amenorrhea

Primary or secondary

Infertility

Men

Decreased libido
Decreased beard and body hair

27 of 29

Hypopituitary�Presentation

Corticotropin deficiency

Fatigue
Decreased appetite
Weight loss
Decreased pigmentation
Abnormal response to stress

Hypotension
Hyponatremia
Fever

Primary Adrenal Insufficiency

Addison’s disease
Fatigue
Decreased appetite
Weight loss
Increased pigmentation
Hyperkalemia
Abnormal response to stress

Hypotension
Hyponatremia
Fever

28 of 29

Hypopituitary�Presentation

Hypothryoidism

Fatigue
Cold intolerance
Puffy skin
Absence of goiter

Diabetes Insipidus

Polyuria
Polydipsia

29 of 29

Thank you