L7: Endocrine Pancreas: Hormones and Regulation

what will hypoglycemia lead to?

1. weakness

2. seizures

3. lethargy

4. potential brain injury if severe or prolonged.

What is Hyperinsulinemia?

Elevated circulating insulin that can drive blood glucose down, causing hypoglycemia.

What is Insulinoma?

Pancreatic beta-cell tumor that secretes insulin, leading to recurrent hypoglycemia; often malignant in dogs.

What is Beta-cell neoplasm?

Tumor of pancreatic beta cells producing insulin.

What is Glucose homeostasis?

Regulation of blood glucose via production, uptake, and storage of glucose

What is Hepatic gluconeogenesis?

Liver production of glucose from non-carbohydrate sources

what are the causes of hypoglycemia due to artifact (false decrease)?

1. improper sample handling

2. bacterial contamination

how does improper handling lead to a false decrease in glucose?

glycolysis by RBCs and WBCs

how does bacterial contamination lead to a false decrease in glucose?

consumption of glucose from bacteria

What is Hepatic immaturity?

Underdeveloped liver function in very young animals (e.g., <6 months) affecting glucose regulation.

What is the Liver as main glucose producer?

The liver is the primary organ for glucose production via gluconeogenesis and glycogenolysis.

What is Glycogenolysis?

Breakdown of glycogen to glucose in the liver.

What is In vitro glycolysis?

Ongoing glycolysis in a collected blood sample that lowers measured glucose.

What is Artifactual hypoglycemia?

False low glucose due to preanalytical factors like glycolysis.

what is an iatrogenic cause of hypoglycemia?

insulin administration

what can lead to decreased glucose production leading to hypoglycemia?

1. liver disease

2. decreased intake

what can lead to increase glucose use, leading to hypoglycemia?

1. sepsis

2. insulinomas

3. decreased counter-regulatory hormones

why can sepsis lead to hypoglycemia?

increase glucose utilization due to a systemic inflammatory response to bacteria (bacteria use glucose)

what are example of insulinomas that lead to hypoglycemia?

1. leiomyoma

2. leiomyosarcoma

3. hepatic and renal tumors

what leads to a decrease in counter-regulatory hormones, leading to hypoglycemia?

Addison’s disease due to lack of cortisol

why are toy breeds susceptible to hypoglycemia?

when they are less then 6 months old, they have hepatic immaturity

what should a clinician do if delays in a blood sample are anticipated?

spin down and freeze sample to avoid false results in glucose

how can glucose concentrations be managed in patients with beta cell neoplasia hypoglycemia?

diet and predisone

What are Fluoride oxalate tubes?

Blood collection tubes with fluoride (glycolysis inhibitor) and oxalate (anticoagulant) that preserve glucose.

what is the pathophysiology of canine insulinoma?

• profound hypoglycemia

• hyperinsulinemia

when is canine insulinoma reversible?

reversible with glucose if caught early

what is used to test for insulinoma?

fluoride oxalate tubes

What is Prednisone?

Glucocorticoid used to elevate blood glucose and support management of insulinoma symptoms.

What is Head-pressing?

Neurologic sign seen in some hypoglycemic dogs.

What is Polyphagia?

Increased appetite; may accompany insulin-secreting tumors.

What is Low glucose threshold?

Glucose value below 60 mg/dL in dogs

what are the values that strongly suggest insulinoma?

• glucose below 60

• insulin greater than 20

what relationship do we focus on for diagnosing insulinoma?

glucose and insulin

what is an exogenous factor that can lead to hypoglycemia?

xylitol toxicity

what are inherited diseases that can lead to hypoglycemia?

1. Pompe

2. von Gierke’s

what factors can lead to increased insulin secretion leading to hypoglycemia?

1. insulinomas

2. leiomyomas

What is Inappropriately high insulin?

Elevated insulin during hypoglycemia, suggestive of insulinoma.

What are Staring episodes?

Neurologic signs (often in ferrets) due to hypoglycemia

what may temporarily reverse hypoglycemia symptoms in a ferret?

sugary treats

What is Type I Diabetes Mellitus?

Autoimmune beta-cell destruction causing insulin deficiency and hyperglycemia.

What is Type II Diabetes Mellitus?

Hyperglycemia with insulin resistance and relative insulin deficiency.

What is Juvenile hypoglycemia?

Idiopathic hypoglycemia in toy/small-breed juveniles

What is Fructosamine?

Glycated serum protein reflecting average glucose over 1–3 weeks; used to monitor diabetes.

what is the common reference interval for glucose in a canine fasting?

60–122 mg/dL

what is the normal reference interval for serum insulin in dogs?

5–20 uU/L

what is the normal reference interval for fructosamine?

90–120 umol/L

what diagnosis would you give if you had a dog with decreased glucose, fructosamine WRI, and insulin WRI?

pathological hypoglycemia

what diagnosis would you give in a dog with decreased glucose, decreased fructosamine, and an insulin value of 35?

insulinoma

what diagnosis would you give in a dog with increased glucose, fructosamine WRI, and insulin increased?

transient hyperglycemia

what diagnosis would you give in a dog with increased glucose, increased fructosamine, and increased insulin?

Type 2 DM

what diagnosis would you give in a dog with increased glucose, increased frucosamine, and decreased insulin?

Type 1 DM