Endocrine Pancreas Pathology Flashcards
what cells make up the exocrine pancreas
acinar cells - contain dark pink zymogen granules
what cells make up the endocrine pancreas
islet cells (A, B, D, F) - light pink staining
what cells makes up the majority of islet cells
beta cells that secrete insulin and amylin
insulin function
major anabolic hormone
decreases BG by:
1. facilitating glucose entry into cells
2. converting glucose into glycogen
3. inhibiting gluconeogenesis and glycogenolysis
also stimulates lipogenesis and protein synthesis
glucagon functions
increases BG by:
1. stimulating glucogenogenesis
2. stimulating glycogenolysis
diabetogenic hormones
hormones that counter the effects of insulin
- glucagon
- glucocorticoids
- thyroxine
- epinephrine
- growth hormone
- progesterone
what are the three categories of endocrine pancreatic pathology
- decreased function
- inflammation
- disorders of growth
diabetes mellitus
hyperglycemia caused by insulin deficiency or resistance
what are the mechanisms of acquiring DM
- inadequate release of insulin by B cells (type I)
- decreased sensitivity of target tissues to insulin (type II)
- antagonism of insulin by other hormones/drugs
- glucagonoma
clinical signs of DM
- hyperglycemia
- glucosuria
- weight loss
- normal/increased appetite
- PU/PD
- protein catabolism
- dec. CHO metabolism
- dec. lipogenesis
- inc. ketones (DKA)
what type of DM is most common in dogs
type I - insulin dependent
what signalment is common in dogs with DM
middle aged/older dogs
genetic basis - some breed predispositions (Keeshonds, Goldens)
pathogenesis of DM in dogs
- vacuolar degeneration of B cells
- diffuse, nonspecific islet cell necrosis
- isletitis (immune mediated destruction of B cells)
- pancreatic adenocarcinoma
- insulin antagonism (Cushing’s, glucagonoma)
what type of diabetes is most common in cats
type II - non-insulin dependent
later stages of disease can become insulin dependent - often still need tx with insulin supplementation
what signalment is common in cats with DM
older, male cats
risk factors for cats to develop DM
- obesity
- islet amyloidosis
- lymphocytic inflammation
- pituitary adenoma (GH secreting tumor)
how does islet amyloidosis occur in cats
B cells deposit amylin within the islet - forms amyloid plaques
how does GH secreting pituitary tumor lead to DM
excess GH overstimulates the liver –> overproduction of IGF-1 –> inhibits insulin
what secondary lesions are often associated with DM
- diffuse hepatic lipidosis
- cataracts
- peripheral neuropathy (plantigrade stance)
- secondary infections (pneumonia, cystitis, dermatitis)
especially emphysematous cystitis
islet hyperplasia
nesidioblastosis
proliferation of islet cells
- NOT associated with endocrinopathy
what species is islet neoplasia common in
dogs, ferrets
can you identify adenoma vs carcinoma of islet neoplasia grossly
NO - need immunohistochemistry
is islet neoplasia associated with an endocrinopathy
yes
insulinoma
beta cell tumors that secrete insulin –> hypoglycemia
commonly metastasizes to liver and adjacent hepatic lymph nodes
what species is insulinomas common in
ferrets
clinical signs of insulinoma
- hypoglycemia
- elevated insulin
- weight loss
- weakness/lethargy
- neurologic signs (seizures, stupor, star-gazing)
ferrets: drooling (ptyalism), pawing at mouth
glucagonoma
alpha cell tumor that secretes glucaon
what species is glucagonoma common in
dogs
what secondary endocrinopathies are associated with glucagonoma
diabetes mellitus
SND (dermatopathy)
gastrinoma
gastrin-producing tumor of the islet cells
(gastrin is NOT usually made by the islets - likely from embryonic malformation)
zollinger-elliison syndrome
hypergastrinemia that leads to:
- antral mucosal hyperplasia
- gastroduodenal ulers
- reflex esophagitis
clinical signs of a gastrinoma
anorexia, vomiting, hematemesis, diarrhea, steatorrhea, weight loss
chemodectoma
“Extra adrenal paraganglioma”
tumor of aortic and carotid bodies
(looks like a pheochromocytoma but located in great vessels)
what species does chemodectoma occur commonly in
dogs (brachycephalics) due to chronic hypoxia
pineal gland function
produced melatonin for pigmentation
what pathology is common in pineal glands of horses
granulomatous inflammation of pineal gland
does horse pineal gland inflammation result in an endocrinopathy
NO
