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Macroscopic Anatomy

• Species Differences

Bovine Equine Porcine Adrenals

Feline Canine Caprine Ovine

Embryonic Development

• – Derived from coelomic mesoderm

• – Derived from neuroectoderm

Canine

Cortex 80% (indented surface) Medulla 20% Rat Adrenal Cortex Cortex:Medulla 2-4:1 (Arcuata) 20% 65% Zone Reticularis 15%

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Homeostatic Model of Adrenal Glands Adrenocortical Growth • Most common endocrine organ with chemically-induced lesions

• Understanding structure and function is important for interpreting the mechanisms and significance of chemically-induced lesions

Stem cells (Sf1-, Gli1+) Zona glomerulosa cells (Sf1+) Zona fasiculata cells (Sf1+) Capsule cells (Sf1-) Zona reticularis cells (Sf1+) Progenitor cells (Sf1+)

Adrenal Organogenesis Adrenal Organogenesis

• Adrenal cortex and : Same primordia • Wnt from capsule targets Dax1 in proliferative cells • Adrenal responds to ACTH; Gonad to LH – Dax1 required for adrenal differentiation • Adrenal rests form in when ACTH is – prevents differentiation of proliferative high cells • Sf1 (steroidogenic factor 1): Marker for • High LH can stimulate adrenal proliferation adrenal cortex; required for adrenal after switch to Gata-4 from Gata-6 formation; induces CYP450 expression – Induced by ACTH

Normal Stress Zona Glomerulosa (Multiformis)

• Histology – Variable between species; glomeruli or arch-like (arcuata) cell cords • Function – Production of mineralocorticoids • Aldosterone Blue=Aldosterone synthase – Preservation of Sodium (Na+) (Blood volume) Green=CYP11-hydroxylase – Excretion of Potassium (K+) Red=Ki-67 • Required for life Chronic stress induces adrenal hyperplasia and hypertrophy (rats), Ulrich-Lai YM, Am J Physiol Endocrinol Metab, 2006, E965.

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Zona Glomerulosa: Endocrine Control

• Release of hormone precursor (Renin) from juxtaglomerular apparatus – Stimulus: low blood volume • Angiotensinogen to angiotensin II • Trophic hormone for zona glomerulosa • Increased aldosterone secretion • Target cells in kidney + - – Increased tubular reasorption of Na , Cl , H20 – Blood volume returned to normal

Zona Fasiculata Zona Reticularis

• Histology • Histology – Columns (fasicles) of cuboidal to – Anastamosing cell cords columnar cells along vascular sinusoids • Function • Function – Production of glucocorticoids – Production of glucocorticoids (not and small amount of sex required for life) steroids (, •Cortisol , progesterone) • • Endocrine control • Endocrine control – CRH () – CRH (Hypothalamus) – ACTH (Adenohypophysis) – ACTH (Adenohypophysis)

Blood Supply to Adrenal Gland Blood Supply to Adrenal Gland

• Cranial, middle, and caudal adrenal arteries (Phrenic, aorta, renal) – Small branches from the accessory phrenic, lumbar, cranial mesenteric, celiac arteries •Cortex – Capsule arterioles – Capillary bed of cortex – Venules at corticomedullary junction • Medulla – Cortico-medullary portal system from capillary bed of cortex – Medullary arterioles

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Subcellular Structure/Function Relationships • Lipid droplets ( esters) • Smooth endoplasmic reticulum • Mitochondria

• Minimal storage of hormone • Steroids are hydrophobic molecules diffuse out of cells

Steroidogenesis Adrenal Cortex Steroid Hormones • ACTH (cAMP second messenger) • 17-carbon steroid nucleus – ↑StAR protein (steroidogenic acute regulator protein – Cholesterol is precursor • Moves cholesterol to inner mitochondrial membrane • Cytochrome P450 enzymes – ↑Cyp11A1 (Rate limiting step) – Mitochondria, SER, Shuttling • Mitochondria • Secretion – Side chain cleavage (Cyp11A1) – Circadian rhythm – Hydroxylation to Pregnenalone – Nocturnal animals (rats, mice, cats): High at night • SER – Daytime animals (dogs, humans): High in morning – Converted to 11-Deoxycorticosterone – Decreased secretion with age (increased in dogs) • Mitochondria • Bound in serum (90%) to CBG (transcortin) – Hydroxylated to Corticosterone or Cortisol • Metabolized in liver (hydroxylated and conjugated)

Acetate ACAT Cholesterol HDL Major Glucocorticoids HO Cholesterol nCEH Esters LDL **CYP11A1** O O O . Cortisol . Corticosterone CYP17 OH CYP17

Pregnenalone 17-OH- . Fish (teleosts) . Amphibians HO HO HO Pregnenalone 3ß-OH-STEROID DE-OH-ASE- 3ß-OH-STEROID Dehydroepiadrosterone . Hamsters . Reptiles DE-OH-ASE- 4,5 ISOMERASE O 4,5 ISOMERASE O O . Dogs (similar to . Birds OH CYP17 CYP17 humans) Progesterone 17-OH- . Rats O O Progesterone O CH OH CYP21 CH2OH CYP21 CH OH . Cats . Mice 2 2 O HO O O O . Nonhuman primates . Rabbits CYP11B2 OH . Humans 11-Deoxy- 11-Deoxycortisol O O corticosteroneO Aldosterone CH OH CYP11B1 CH2OH CYP11B1 2 HO O HO O OH Corticosterone Cortisol O O ACAT: acyl-CoA:cholesterol acyltransferase, nCEH: neutral cholesterol ester hydrolase

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ACTH ACAT Cholesterol HO Cholesterol HO Cholesterol nCEH Esters cAMP CYP11A1 **CYP11A1** O O O O O O CYP17 OH CYP17 CYP17 OH CYP17

Pregnenalone 17-OH- Pregnenalone 17-OH- HO HO HO HO HO HO 3ß-OH-STEROID Pregnenalone Dehydroepiadrosterone 3ß-OH-STEROID Pregnenalone Dehydroepiadrosterone 3ß-OH-STEROID DE-OH-ASE- 3ß-OH-STEROID DE-OH-ASE- DE-OH-ASE- DE-OH-ASE- 4,5 ISOMERASE O 4,5 ISOMERASE O O 4,5 ISOMERASE O 4,5 ISOMERASE O O OH CYP17 OH CYP17 CYP17 CYP17 17-OH- Progesterone 17-OH- Progesterone O O O O O Progesterone O Progesterone Androstenedione CYP21 CH OH CH OH Androstenedione CH OH CYP21 CH OH CH OH CH2OH 2 CYP21 2 2 2 CYP21 2 HO HO O O O O O O O O OH CYP11B2 OH CYP11B2 11-Deoxy- 11-Deoxy- 11-Deoxycortisol O O 11-Deoxycortisol O O corticosteroneO O corticosterone Aldosterone CH OH Aldosterone CYP11B1 CH OH CH OH CYP11B1 CH2OH CYP11B1 2 2 CYP11B1 2 O O HO O HO O HO HO OH OH Corticosterone Cortisol Corticosterone Cortisol O O O O

Acetate ACAT Cholesterol Cholesterol HDL HO HO Cholesterol nCEH Esters LDL CYP11A1 **CYP11A1** O O O O O O CYP17 OH CYP17 CYP17 OH CYP17 Pregnenalone 17-OH- Pregnenalone HO HO HO HO 17-OH- HO HO 3ß-OH-STEROID Pregnenalone Dehydroepiadrosterone Pregnenalone 3ß-OH-STEROID DE-OH-ASE- 3ß-OH-STEROID DE-OH-ASE- 3ß-OH-STEROID Dehydroepiadrosterone DE-OH-ASE- DE-OH-ASE- 4,5 ISOMERASE O 4,5 ISOMERASE O O 4,5 ISOMERASE O 4,5 ISOMERASE O O OHCYP17 OH CYP17 CYP17 CYP17 17-OH- 17-OH- Progesterone Progesterone O O Progesterone O O O Progesterone O CH OH CYP21 CH OH CH OH Androstenedione CH OH CYP21 CH OH CH OH Androstenedione 2 2 CYP21 2 2 2 CYP21 2 HO HO O O O O O O O O OH CYP11B2 OH CYP11B2 11-Deoxy- 11-Deoxy- 11-Deoxycortisol 11-Deoxycortisol O O O O O corticosteroneO corticosterone Aldosterone CH OH CH OH CYP11B1 CH2OH CYP11B1 2 Aldosterone CH2OH CYP11B1 2 O O O O HO HO HO HO Angiotensin II OH OH + K Corticosterone Cortisol Corticosterone Cortisol O O O O

Cynomolgus Monkey

17-HSD: 17-hydroxysteroid dehydrogenase

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Cynomolgus Monkey: CYP17A IHC Cynomolgus Monkey: CYP11B2 IHC

Cynomolgus Monkey: Ki-67 Fetal Adrenal Cortex: Function

Fetal Maturation • Lung maturation – Surfactant production • Enzyme induction – Fetal gut, retina, pancreas, gland, brain • Glycogen deposition –Liver

Fetal Adrenal Cortex Fetal Adrenal Cortex Primates, Mice, Sloth, Armadillo • Histology • 80% of cortex in humans – Typical histology in fetus • 90% of cortex in fetal armadillo – Fetal glucocorticoid production • ‘X-Zone’ in mice – Primates • Large cells with abundant, eosinophilic • Fetal cortex undergoes apoptosis & atrophy after cytoplasm birth • Degenerates after birth and is replaced by –Mice the definitive cortex with proliferation in the • Fetal cortex undergoes degeneration and atrophy after birth (X-zone) zona fasciculata

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Fetal Adrenal Cortex: Tamarin Neonate X-Zone in Mice

• Zonation is complete at birth (ZG, ZF, no ZR) • X-zone is adjacent to the medulla • Degeneration – Males: Near , fatty degeneration – Virgin Females: Slow regression – Pregnant Females: Regresses during first pregnancy • Vacuolar degeneration • Function is unknown, may catabolize progesterone, may be remnant of adrenal primordia

X-Zone in Neonatal Mice

Adrenal Dysplasia Cloned Calves • Japanese Black and other breeds Adrenal Cortex: • Prolonged gestation • Heavy birthweights Pathology • Stillborn calves • High neonatal mortality

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Adrenal: Normal Adrenal Dysplasia Cloned Calves Cloned Calves

Accessory Adrenal Tissue Accessory Adrenal Tissue: Cat Mesosalpinx

• All species, prominent in horses • Near adrenal or (ovary or testes) • Only consists of cortex; all three layers • No medulla

Accessory Adrenal Tissue: Foal Accessory Adrenal Tissue: Mare Gonad Ovary

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Peracute Adrenocortical Hypoadrenocorticsm Insufficiency • Diffuse cortical necrosis/hemorrhage • Peracute adrenocortical insufficiency – Trauma: Calves; dystocia – Overexertion: Horses, wild animals – Waterhouse-Friedrickson Syndrome – Septicemia: Calves • Thrombosis of adrenal vessels • Chronic adrenocortical insufficiency – Bacterial or parasitic emboli – Addison’s Disease • Toxemia – Intestinal disease • Necrotizing inflammation; torsion – Certain drugs (O,P’-DDD, Lysodren, mitotane)

Septic Infarct - Dog

Chronic Hypoadrenocorticism Pathogenic Mechanisms Chronic Hypoadrenocorticism

• Diffuse, bilateral destruction of the Serum Electrolytes*

adrenal cortex (all 3 layers) HYPOAC NORMAL

–Inflammation (Adrenalitis)  SODIUM (mEq/L) = < 135 140-160

• Infectious  POTASSIUM (mEq/L) = 5.8+ 3.7-5.5 • Autoimmune  CHLORINE (mEq/L) = < 100 100-120 –Necrosis  Na:K RATIO = < 27.1 30:1 –Mineralization

*VALUES FROM DOGS

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Plasma ACTH: Primary and Secondary Cortical Insufficiency Chronic Adrenal HYPOADRENOCORTICISM 180015 14 Insufficiency 160013 12 Addison’s-Like Disease 140011 10 1200 9 Thomas Addison, MD 8 607 Lancet 6 1855 405

PLASMA ACTH (pg/ml) PLASMA 4 203 2 0 1 0 NORMAL DOGS SECONDARY ADRENAL PRIMARY ADRENAL

Chronic Hypoadrenocorticism Addison’s Disease

• Idiopathic cortical atrophy – Immune-mediated – All 3 zones affected •Early – Lymphoplasmacytic inflammation • Late – Fibrosis, atrophy – Pituitary corticotroph hypertrophy/hyperplasia

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Infectious Adrenalitis Granulomatous Adrenalitis Histoplasma capsulatum • Histoplasma capsulatum • Blastomyces dermatitidis • Mycobacterium tuberculosis • Toxoplasma gondii

• Suppression of local cell-mediated immunity

Degeneration & Mineralization of the Adrenal Cortex Cat, Dog, Non-Human Primates

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Hypoadrenocorticism: Dogs Clinical Signs

• Mental Depression • Anorexia • Vomiting, Diarrhea (hemorrhagic) • Dehydration • Hypotension • Bradycardia • Muscle Weakness • Unfavorable Response to Stress

Hypoadrenocorticism Proliferative Lesions of Adrenal Hypercalcemia Cortex

• Increased total and bound calcium HYPERPLASIA – Ionized calcium not increased • Mechanisms  Spindle Cell (Mice) – Hemoconcentration – Greater binding to plasma proteins  Extracortical Nodular (Dog) – Increased complexed calcium (citrate,  Focal, nodular (Dogs, Rats) phosphate) – Increased renal tubular reabsorption  Diffuse Zonal (ACTH; Electrolyte – Not dependent on intestinal calcium Changes) absorption  Gonadectomy- Associated (Ferrets)

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Extracortical Nodular Hyperplasia

ADRENAL CORTEX

DOG

AGE-RELATED CORTICAL HYPERPLASIA

AGE OF DOG

Nodular Hyperplasia

ADRENAL CORTEX

Dog, Rat, Ferret

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Adrenal Cortex (F344 Rat) Focal Hyperplasia

Hyperplasia (rat), large cell and vacuolar BrdU

84

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Hyperplasia: Zona Reticularis, Bovine Adrenal Cortex -Excess Zonal Hyperplasia

• Glomerulosa – Decreased Na+, Increased K+

• Fasciculata – Increased ACTH

• Reticularis

Diffuse Hyperplasia: Zona Glomerulosa Secondary Hyperaldosteronism

PATHOGENIC MECHANISMS • Decreased Blood Volume to Kidney – Renal Vascular Disease • Decreased Blood Pressure – Blood Loss, Shock • Chronic Sodium Depletion – Kidney Disease • Increased Blood Potassium – Muscle Injury, Kidney Disease

Diffuse Hyperplasia (ACTH): Congenital Adrenal Hyperplasia Zona Fasiculata/Reticularis Rabbits • Severe cortical hyperplasia (6x) • Deficiency of CYP11a1 (side chain cleavage, P450scc) • Decreased corticosterone • Increased K+, normal Na+ • Increased 11-hydroxylase and P45017a activity

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Normal Hyperplasia Spindle Cell Hyperplasia Subcapsular

• Common in adult mice – Progresses to neoplasia

• Infrequent in rats and hamsters

Proliferative Lesions of the Adrenal Cortex

NEOPLASIA

Multipotential Subcapsular Adrenocortical Tumors Non-Steroidogenic Progenitor • Humans – 5% of people over 50 years, incidental, nonfunctional • Carcinoma is rare (500 per year USA) • Dogs: Similar to humans – Functional tumors more common • Gonadectomy – Goats, ferrets, hamsters, and mice

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Cortical Hyperplasia & Neoplasia Mechanism: Increased LH Cortical Adenoma & Carcinoma • Gonadectomy – Species: Mice, Ferrets, Goats • Transgenic mice deficient in inhibin – Cross with mice lacking GnRH & no tumors FUNCTIONAL NON-FUNCTIONAL ENDOCRINOLOGICALLY ENDOCRINOLOGICALLY • Estrogen receptor agonist/antagonists ACTIVE INACTIVE • SERMs (↑LH) • Ionizing radiation, Chemicals (DMBA) • Ovarian Follicle Destruction

•(↓)E2, (↑) LH • ALDOSTERONE • CORTISOL • SEX STEROIDS (Z. MULTIFORMIS) (Z. FASCICULATA) (Z. RETICULARIS)

Cortical Adenoma - Dog

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Vena Cava Invasion Cortical Carcinoma with Trophic Atrophy

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Cortical Carcinoma Pulmonary Metastasis

Hypercortisolism Hypercortisolism Hematopoietic Cells

EFFECTS MECHANISM Cushing’s Cushing’s Disease Syndrome • LYMPHOPENIA • LYSIS • EOSINOPENIA • LYSIS, SEQUESTRATION •NEUTROPHILIA • (+) BONE MARROW (B.M.) • LEUKOCYTOSIS • (+) B.M. (-) DIAPEDESIS ACTH-Secreting Functional • POLYCYTHEMIA •(+) B.M. Adrenal Cortex Tumor • THROMBOCYTOSIS •(+) B.M. Tumor

Hypercortisolism Hypercortisolism Osteoporosis Carbohydrate Metabolism • Inhibition of osteoblasts • Stimulation of gluconeogenesis – Protein catabolism • Catabolism of bone – Lipolysis – Diminished amino acids available – Increased glucose production • Accumulation of liver glycogen • Decreased intestinal calcium absorption • Decreased glucose utilization – Down regulation of insulin receptors – Peripheral insulin resistance • Lowered blood calcium  increased PTH • Increased blood glucose (diabetogenic) – Increased urinary calcium excretion

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Cortical Excess in Dogs Clinical Signs

PERCENT • Polyuria/Polydipsia 82 • Pendulous Abdomen 67 • Hepatomegaly 67 • Alopecia 63 • Lethargy 62 • Polyphagia 57 • Muscle Weakness 57 • Anestrus 54

Cortical Excess in Dogs Clinical Signs

PERCENT • Obesity 47 • Muscle Atrophy 35 • Comedones 34 • Panting 31 • Testicular Atrophy 29 • Hyperpigmentation 23 • Calcinosis Cutis 8

Cortical Excess in Dogs Cortisol-Excess in Dogs Laboratory Laboratory

• Increased Alkaline Percent Percent 86 Phosphatase • Hypophosphatemia 38 • Increased Total CO 33 • Eosinopenia 84 2 • Mature Leukocytosis 32 • Increased Alanine 53 • Erythrocytosis 17 Amino Transferase • Lymphopenia 14

• Hypercholesterolemia 48

• Hyperglycemia 45

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Cortisol-Excess in Cats Cortisol-Excess in Cats Clinical Signs Laboratory

PERCENT Percent • Polyuria, Polydipsia 94 • Hyperglycemia 100 • Abdominal Distension 94 • Hypercholesterolemia 86 • Increased Appetite 89 • Glycosuria 82 • Alopecia 72 • Lymphopenia 67 • Muscle Wasting 67 • Eosinopenia 58 • Obesity 61 • Mature Leukocytosis 42 • Hepatomegaly 56 • Increased Serum 36 • Infection(s) 39 Alkaline Phosphatase • Atrophy of Skin 33

Serum Cortisol Assay Cortisol-Excess: Diagnosis Low Dose Dexa. Suppression Test • Resting cortisol & 6-8 hr. • Baseline • Normal “Stressed” Dog: Serum cortisol <1.0 ug/dl post-injection • Dexamethasone Suppression – Low Dose: 0.015 (0.01) mg/kg IM (IV) • Cortisol-Excess: <50% Suppression from – High Dose: 1.0 mg/kg IM (IV) Baseline – 95% Dogs with Pituitary-Dependent • ACTH Stimulation – 100% Dogs with Adrenal-Dependent

Cortisol-Excess: Diagnosis Cortisol-Excess: Diagnosis High Dose Dexa. Suppression Test ACTH Stimulation Test • Resting cortisol and 8 hr. • Separates “Stressed” Normal from Cortisol-Excess Dogs • Pituitary-Dependent: • ACTH: 1 unit/lb. B.W. (>40 units) – 85% suppress to <1.5 ug/dl • Baseline and 2 hr. serum cortisol – 15% fail to suppress to <1.5 ug/dl • Normal Dog: • Adrenal-Dependent: – Resting serum cortisol: 1-4.8 g/dl – 2 hr. Post-ACTH: 5-26 g/dl – 80% resistant to suppression – 20% suppress to 50% baseline

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Cortisol-Excess: Diagnosis Cortisol-Excess: Diagnosis ACTH Stimulation Test Plasma ACTH • Pituitary-Dependent: • Technically difficult assay • Relatively expensive • 85% Hyper-responsive • Not readily available • 15% Normal • ACTH adheres to glass • Adrenal-Dependent: – Cold, plastic, heparinized syringes – Store in plastic tubes • 50% Hyper-responsive • Thermal liable • 50% Non-responsive – Refrigerated centrifuge – Shipment on dry ice

Cortisol-Excess: Dogs Breed Distribution of Cortisol- Pro-Opiomelanocortin Peptides Excess in Dogs • Suppressed plasma levels: BREED PERCENT • Poodle 33 –ACTH – Miniature (29/38) – β-Lipotrophin (β-LPH) • Dachshund 25 • Boxer 5 – β-Endorphin (β-END) • Brittany Spaniel, Beagle, 2 Each –α-MSH Lab, Retriever, Chihuahua, Manchester Terrier, Welsh Terrier • Miscellaneous Breeds (19) 1 Each

Hyperadrenocorticism Trilostane Treatment HO Cholesterol CYP11A1 • Competitive inhibitor of 3β-hydroxysteroid O O O dehydrogenase CYP17 OH CYP17 Pregnenalone 17-OH- HO HO HO Pregnenalone 3ß-OH-STEROID DE-OH-ASE- 3ß-OH-STEROID Dehydroepiadrosterone DE-OH-ASE- • Can be used for PDH or ADH 4,5 ISOMERASE O 4,5 ISOMERASE O O OHCYP17 CYP17 Progesterone 17-OH- O O Progesterone O CYP21 CH OH CH OH Androstenedione CH2OH 2 CYP21 2 O HO O O O CYP11B2 OH 11-Deoxy- 11-Deoxycortisol O O corticosteroneO Aldosterone CH OH CYP11B1 CH2OH CYP11B1 2 O O HO HO OH Corticosterone Cortisol O O

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Trilostane: Effect on Adrenal Glands

• Adrenal glands remain responsive to high plasma ACTH that follow blockade of steroid biosynthesis • Adrenal glands become progressively enlarged (over 6-12 mos) with altered echogenicity and nodular hyperplasia • Over-stimulation of adrenal glands may exhaust secretory capacity and result in hypoadrenocorticism

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Hyperadrenocorticism in Salmon Hyperadrenocorticism in Salmon

Fluvial Migration (Spawning) FLUVIAL MIGRATION (SPAWNING) • Swim continuously without eating • Increased Hypothalamic-Pituitary-Adrenal • Osteoporotic Changes in Bone activity • Overgrowth of Cartilage in Jaw • Muscle catabolism • Accelerated (‘Premature’) Aging • Hyperpigmentation – Salmon ages in 2-4 weeks as much as a • Atrophic (thin) skin human in 20-40 years • Fungal infections of scales – Die shortly after spawning

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Hyperadrenocorticism in ADRENAL CORTICAL Spawning Salmon PROLIFERATIVE LESIONS IN FERRETS

Adrenal Cortex Lesions: Ferrets Adrenal Cortex Lesions: Ferrets

• Hyperplasia • Pathogenesis – Nodular – Gonadectomy at an early age – Often bilateral • Increased GnRH • Adenoma • Secondary increase in FSH and LH – Abnormally long photoperiods of pet ferrets –Unilateral • Light cycles >8 hours increase GnRH and LH • Carcinoma secretion –Unilateral • Normally crepuscular; sleep 14-18 hours per day and are active during dawn and dusk

Development of the adrenal gland and gonads from the urogenital ridge Hyperestrogenism: Ferrets

• Vulvar enlargement • Bilaterally symmetrical alopecia – Abdomen, rear legs • Possible palpable mass at cranial pole of kidney – Left > right • Females (70%) > males (30%)

Bielinska M et al. Vet Pathol 2006;43:97-117

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Hyperadrenocorticism in Ferrets Endocrinologic Changes

• Plasma Estradiol-17β – Elevated in >88% of the cases – No increase to ACTH – Decreased after adrenalectomy – Produced by tumor or peripheral conversion of adrenal androgens – Feminization and bone marrow depression

Hyperestrogenism: Ferrets Hyperadrenocorticism in Ferrets

• Anemia, thrombocytopenia •Cortisol • Pyometra, endometrial hyperplasia – Plasma levels within or below normal range • Prostate enlargement – Lack of exaggerated increase by ACTH – Squamous metaplasia – No decrease following adrenalectomy and • Prolonged estrus lack of atrophy of contralateral gland • Islet cell tumors in same animal – Urinary cortisol:creatinine increased in ferrets with adrenal tumors (6x10-6) compared to – 35% of the time controls (0.3x10-6)

Hyperestrogenism in Ferrets Treatment

LUPRON (LEUPROLIDE) GnRH ANALOG

• Decreases production of LH & FSH from by down-regulating GnRH receptors in pituitary when administered chronically • Transitory regression of clinical signs, often recurrence after 3-4 months • Expensive • Long-term effects are unknown

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Adrenal gland, carcinoma; neutered ferret

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PCNA Immunohistochemistry

Normal Hyperplasia

Adenoma Carcinoma

Regulation of StAR expression Associated Diseases

• Stump pyometra • Vaginitis • Urogenital cystic disease • Prostatomegaly – Squamous metaplasia

Bielinska M et al. Vet Pathol 2006;43:97-117

ADRENAL MEDULLA

• Not essential for life

• Contrast to adrenal cortex: – Life-Sustaining Function Mineralocorticoid Secretion – Aldosterone Production: ↑ K+ Excretion; ↑ Na+ Reabsorption

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ADRENAL MEDULLA EMBRYOLOGIC DERIVATION

NEUROECTODERM FROM NEURAL CREST

Adrenal Medulla Adrenal Medulla

• Modified sympathetic nerves • Chromaffin Cells: 3 types of cells – ‘Modified Ganglion’ – Epinephrine Cells (66-75%) – Derived from the neural crest – Norepinephrine Cells (25-33%) • Blood supply – Small granule-containing cells (SGC) – Adrenal cortex portal system • Neuron-like cells, 4% in mice, 1% in rats • Induction of PNMT (formation of epinephrine) • Other Peptides – Separate arterioles – Met-enkephalin, substance P, neurotensin

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Adrenal Medulla

• Less common site of toxic manifestations • Proliferative lesions – Important in the rat – Less common in the mouse • Intermingling of cortical and medullary tissue – Human, pig, some strains of rats

CHEMISTRY AND BIOSYNTHESIS OF CATECHOLAMINE HORMONES

COMPARATIVE PHYSIOLOGIC EFFECTS

NOREPINEPHRINE • Restricted Physiologic Activity

• Generalized Vasoconstriction (α1) – Peripheral Resistance Increased – Blood Pressure Increased

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COMPARATIVE PHYSIOLOGIC EFFECTS COMPARATIVE PHYSIOLOGIC EFFECTS

NOREPINEPHRINE NOREPINEPHRINE

• Cardiac Activity: Minimal Effects • Metabolism: Little Effect • Dilatation of Pupil

• Gastrointestinal Functional Inhibited (β2) • Bronchiolar Dilatation: Little Effect – Sphincter Tone Increased

COMPARATIVE PHYSIOLOGIC EFFECTS COMPARATIVE PHYSIOLOGIC EFFECTS

EPINEPHRINE EPINEPHRINE

• Diverse Physiologic Activity • Cardiac Activity: Greatly Increased (β2) – ↑ Heart Rate • Selective Vasoconstriction (α1) – Skin, Kidney – ↑ Stroke Volume – Weak Effects on Peripheral Resistance – ↑ Output – Minimal Effects on Blood Pressure

• Selective Vasodilatation (β2) – Skeletal Muscle – Coronary Arteries

COMPARATIVE PHYSIOLOGIC EFFECTS Immunoreactivity

EPINEPHRINE • Tyrosine hydroxylase: All chromaffin cells – Cytosolic (independent of granules) • Metabolism (β2): potent stimulation of: – Basal Metabolic Rate (BMR) – All tumors produce this enzyme – Glycogenolysis • Chromogranin A: All chromaffin cells – Lipolysis – Secretory Granules (variable in tumors) – Blood Glucose Increased • PNMT: Only Epinephrine cells

• Bronchiolar Dilatation (β2): – Cytoplasmic (variable in tumors) – Respiratory Rate Increased

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Tyr Hydroxylase, Chromogranin A PNMT (Epinephrine Cells)

DISEASES OF ADRENAL MEDULLA ADRENAL MEDULLARY (?) INSUFFICIENCY

• HYPERFUNCTION • HYPOFUNCTION No recognized disease of hypofunction

Less able than normal to response to a stressful situation (?)

ADRENAL MEDULLA Proliferative Diseases • Hyperplasia (rats, cattle) – Focal or diffuse – Preneoplastic • (rats, dogs, horses, cattle) – Pheochromocytoma – Malignant Pheochromocytoma • Neuronal – Neuroblastoma (dogs, rats) – Ganglioneuroma (rats)

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ADRENAL MEDULLA Proliferative Diseases

• Secretory (Chromaffin) Cell Neoplasms – Pheochromocytoma (benign) • May start as hyperplasia • Expanding medullary mass • Well differentiated • Behavior – Space-occupying mass – Excess catecholamine secretion

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Pheochromocytoma Pheochromocytoma: Horse Bovine, Bilateral

Adrenal Medulla: F344 Rat INTERSPECIES COMPARISON OF Pheochromocytoma PHEOCHROMOCYTOMAS RAT MOUSE HUMAN

 LIFETIME > 80% <5% <0.09%* FREQUENCY

 SEX MALE NONE NONE PREDILECTION HORMONES NONE NONE  INDUCING AGENTS DRUGS, TOXINS DIETARY FACTORS

 CELL TYPE NE E+NE E+NE

*BASED ON UNSELECTED AUTOPSY SERIES

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Functional Effects of Neoplasms

• Space-occupying mass – Pressure on posterior vena cava – Tumor thrombus – Penetration of adrenal capsule and growth on peritoneal surfaces • Hormone secretion – Epinephrine or Norepinephrine

Functional Effects of Laboratory Diagnosis of Adrenal Pheochromocytoma Medullary Tumors

• Paroxysmal tachycardia (E) (episodic • Laboratory Diagnosis secretion) – Hormone secretion may be episodic and • Hypertension (NE) variable • Profuse sweating; hyperhidrosis (NE) – Urinary hormones or metabolites are more reliable indicators • Hyperglycemia (E) • Catecholeamines • Vasoconstriction, arteriosclerosis (NE) • Vanillymandelic acid (VMA) – major metabolite • Cardiac hypertrophy (E and NE) • Urinary metanephrines • Urinary homovanillic acid (HVA) • Posterior edema (from space occupying mass)

Differential Diagnosis of Adrenal Medullary and Cortical Tumors

• Chromaffin Reaction – Dichromate fixative oxidizes catecholeamines to form brown-black pigment – Differentiate cortical and medullary neoplasms

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ADRENAL MEDULLA Proliferative Diseases

• Malignant Pheochromocytoma • Local invasion • Invasion into the posterior vena cava

Malignant Pheochromocytoma Malignant Pheochromocytoma

• Large neoplasm near the kidney • Vascular invasion with thrombi in the posterior vena cava • Invasion of adrenal capsule and periadrenal tissues • Necrosis and hemorrhage in the tumor • Metastases to extra-adrenal sites

Malignant Pheochromocytoma Malignant Pheochromocytoma

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ADRENAL MEDULLA Proliferative Diseases

• Neuroblastoma – Young animals

– Poorly differentiated round cells

– Can penetrate adrenal capsule and spread to peritoneal surfaces

– Vascular invasion

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Chromogranin A IHC Synaptophysin IHC

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ADRENAL MEDULLA Proliferative Diseases

• Ganglioneuroma – Expanding medullary mass

– Composed of neurons and axons

– Benign

Metastatic Neoplasms to Medulla

• Often bilateral

• Incidence greater than in the adrenal cortex

• Tumor emboli lodge in the adrenal veins

Multiple Endocrine Tumors Aged Rats

• Pituitary Adenoma • C-Cell tumors • Pheochromocytoma

• Hypothesis: – Common tumors in older rats – Inherited multicentric genetic predisposition of neuroendocrine cells

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