Pancreas and Calcium Regulation 8.25 Flashcards
Alpha Cell
Secretes glucagon
Beta Cell
Secretes insulin and C-peptide
Control of Insulin Secretion
Effect of Insulin on NaK ATPase and Ca Channels
Glucagon Control Loop
Glucagon-Like Peptides (GLPs)
- Secreted from gut in response to feeding
- Acute - Increases insulin response to glucose 3. Chronic - Increases beta-cell mass
Blood Glucose Pathway
Types of Diabetes
- Type 1 (T1DM) = islet cell destruction • Type 2 (T2DM) = insulin resistance
- Gestational Diabetes
• Secondary hyperglycemia (e.g. acromegaly, Cushing’s syndrome)
Current View of Pathogenesis of T1DM
Genetic Susceptibility + Environment (viral infection?)
–> autoimmune attack of beta cell by lymphocytes and immunoglobulins
–> loss of insulin secretion (permanent)
Hypothetical Pathogenesis of T2DM
Primary cellular defect→decreased glucose uptake
(insulin resistance)
PLUS
Primary Liver Defect→decrease in hepatic glucose
uptake; failure to decrease gluconeogenesis
PLUS
RELATIVE beta cell defect→inadequate insulin
response (although usually “hyperinsulinemic”)
LEAD TO Hyperglycemia (Insulin resistance with increased
insulin but decreased response to insulin)
Long Term Complications of DM
Retinopathy (blindness)
Nephropathy (dialysis/transplantation) Neuropathy
Cardiovascular disease (heart/circulatory system) Skin (poor wound healing)
Pregnancy – increase size of baby; increase problems in pregnancy
Metabolic Syndrome
WHO – 1998 – Insulin resistance (fasting glucose) and 2 of the following criteria a. hypertension
b. dyslipidemia (high triglycerides and/or low HDL)
2 c. obesity (BMI>30 kg/m )
visceral obesity = waist circumference >102cm (male) >88cm (female) d. microalbuminuria (renal function)
Calcium Feedback Loop
Calcium Receptor Mechanism
Hypercalcemia
Hypercalcemia is caused by an increase in PTH secretion. Primary hyperparathyroidism (usually a parathyroid adenoma)
Hypercalcemia results in a suppression of PTH secretion. Vitamin D intoxication, Hypercalcemia of malignancy (caused by PTHrp)
