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SI SessionSI Session
Metabolism
Spring 2010
For Dr. Wright’s Bio 6 ClassDesigned by Pyeongsug Kim ©2010 [email protected]
Review your understanding of catabolism and anabolism.Be able to discuss a mechanism by which each of the following affects blood glucose levels (i.e., does it increase or decrease blood sugar, and HOW):
InsulinGlucagonsGrowth hormone/insulin-like growth factorsEpinephrineGlucocorticoidsThyroxine
Compare and contrast type I and type II diabetes mellitus with respect to:Age of onsetWhy blood glucose levels are highIs insulin deficient?Recommended treatmentAre beta islet cells damaged?
How does parathyroid hormone and/or vitamin D3 (1, 25-dihydroxyvitamin D3) affect:Reabsorption of calcium from intestineReabsorption of calcium in kidneysResorption of bone
(Think: does it tend to put more calcium in the blood, or less?)What are the consequences of having low blood calcium? (review question!)
• Catabolism
C A + B + energy Breaking down into smaller molecules
Chemical reactions in Metabolism:Chemical reactions in Metabolism:• Anabolism
A + B + energy C Form larger molecules
Reactants Product
Reactant Products
+ energy
+ energy
Designed by Pyeongsug Kim, ©2010
*Generally….High levels due to CATABOLISM. Low levels due to ANABOLISM.
Designed by Pyeongsug Kim, ©2010
Stimulates glycolysis (Catabolism). increase blood glucose.
Stimulate glycogenesis(Anabolism). decrease blood glucose.
The hormones affect Blood glucose levels:
InsulinGlucagonsGrowth hormoneInsulin-like growth factorsEpinephrineGlucocorticoids
Picture from http://www.projectswole.com/diet/how-to-manipulate-insulin-for-fat-loss-and-muscle-gain/
Designed by Pyeongsug Kim, ©2010
InsulinInsulin↓ Blood glucose by stimulating… -Cellular uptake of glucose -Conversion of glucose to glycogen and fat.
↑Blood glucose
In Beta cell↑insulin secretion
In Alpha cell↓Glucagon secretion
Cells uptake glucose
Liver/muscle: Glucose Glycogen
Adipose tissue: Glucose Triglyceride
↓Blood glucose
_____________: Glucose Glycogen
_____________: Glucose Triglyceride
Glycogenesis
Lipogenesis
Anabolism!!
“-lysis”: Breakdown to smaller molecules“-genesis”: Making to a big molecules
Designed by Pyeongsug Kim, ©2010
*Insulin is __________ of carbohydrate and lipids.anabolism
(secreted by Pancreas (Beta cells)
GlucaconGlucacon↑ Blood glucose by stimulating… -Making glucose from glycogen and noncarbohydrates (triglyceride and amino acids) -Glycogenolysis(breakdown Glycogen into glucose) in the liver. -Glucogenesis
↑Blood glucose
In Beta cell↓ insulin secretion
In Alpha cell↑ Glucagon secretion
↓ Cells uptake glucose
Liver/muscle: Glucose ← Glycogen
Adipose tissue: Glucose ← Triglyceride
↑ Blood glucose
_____________: Glucose ← Glycogen
_____________: Glucose ← Triglyceride(or noncarbohydrate)
Glycogenolysis
Gluconeogenesis
“-lysis”: Breakdown to smaller molecules“-genesis”: Making to a big molecules
Catabolism!!
Designed by Pyeongsug Kim, ©2010
(secreted by Pancreas (Alpha cells)
-Both sympathetic and parasympathetic nerves innervate pancreas-Sympathetic, along with epinephrine, stimulates glucagon secretion increase blood glucose-Parasympathetic stimulates insulin secretion ↑ gastrointestinal activity (digestion) decrease blood glucose
Designed by Pyeongsug Kim, ©2010
ANS system activity in metabolismANS system activity in metabolism
Designed by Pyeongsug Kim, ©2010
Growth hormone(GH)Growth hormone(GH)-Secreted by A.pituitary glands.-Controlled by GHRH(from hypothalamus)
-stimulates growth in children and adolescents.-More secreted GH during stress and fasting in adults.-increased when fasting, stress, low blood glucose and high amino acid by skeletal muscle.
Picture from http://adolescents.wordpress.com/
Designed by Pyeongsug Kim, ©2010
Insulin-like Growth factors (IGFs)Insulin-like Growth factors (IGFs)-”Somatomedians” -Polypeptides(protein) produced by liver or many tissues.-mediators of some of GH actions. Cell division Cartilage and bone growth Protein synthesis in muslce & other organs.-Not mediated of GH actions. Lipolysis decreased glucose utilization.
Designed by Pyeongsug Kim, ©2010
Insulin-like Growth factors (IGFs)(Cont’d)Insulin-like Growth factors (IGFs)(Cont’d)
From Dr. Wright’s Bio6 powerpoint
Designed by Pyeongsug Kim, ©2010
Growth hormone(GH)Growth hormone(GH)↑ Blood glucose by stimulating… - ↓cellular glucose uptake; Glycogenolysis in the liver
↓ Blood glucosee.g. fasting
In liver ↑Glycogenolysis
↓ Cells uptake glucose
Muscle and other organ: Protein← amino acids
Adipose tissue: fatty acids← Triglyceride
↑ Blood glucose
↑ amino acid in Blood
↓ amino acid in Blood
↑ fatty acids in Blood
↑GH in Anterior pituitary
↑GnRH in Hypothalamus
(secreted by Anterior Pituitary glands)
Hormones for catabolism of carbohydrates and lipids
GlucagonGrowth hormone(GH)EpinephrineGlucocorticoids, Thyroxine
Designed by Pyeongsug Kim, ©2010
*Insulin is __________ of carbohydrate and lipids.anabolism
*However, GH and Thyroxine promotes protein synthesis anabolism of protein.
EpinephrineEpinephrineIncrease in stress.Produced in adrenal medulla↑ Blood glucose by stimulating… -release glucose from liver (Glycogenesis) -Gluconeogenesis(making glucose from noncarbohydates)
GlucocorticoidsGlucocorticoids-Produced in adrenal cortex-Controlled by ACTH-Increased during prolonged fasting or exercise ↑Blood glucose by stimulating… - ↓cell glucose utilization -Gluconeogenesis(making glucose from noncarbohydates) ↑Lipolysis ↑protein breakdown in muscle.
Designed by Pyeongsug Kim, ©2010
Thyroxine(T4)Thyroxine(T4)
-Secreted in thyroxine by TSH.-response to low ATP -Increase cell respiration (to make more ATP) ↑ glucose utilization increase metabolic heat as a result of cell respiration. Cold adaptation!!-participate in body growth and CNS in children. ↑ protein synthesis ↑ BMR(Basal metabolic rate)
-Both hypothyroidism and hyperthyroidism Cause muscle wasting(protein breakdown)
-No direct in lipid metaolism.
Designed by Pyeongsug Kim, ©2010
(secreted by thyroid follicles)
A person with hypothyroidism cannot stand being cold.
Picture from http://abbeygracepink.com/?p=185
Thyroxine(T4) (cont’d)Thyroxine(T4) (cont’d)
Designed by Pyeongsug Kim, ©2010
-act on nearly every cell in the body. -participate in catabolism of carbohydrates and lipids-Tend to elevate blood glucose.-participate in protein synhesis.
“T4 and T3 tend to ELEVATE PLASMA GLUCE and potentiate the effects of other HYPERGLYCEMIC hormones..ie.. NE, E, cortisol, glucagon, and GH”
Diabetes Type 1 Type 2
onset < 20 years > 40 years
Symptoms Rapid Slow
Proportion 10% 90%
Ketoacidosis? Common Rare
Obesity rare common
Beta cells damaged? Yes No
Insulin secreted? Decreased May be increased
Immunity to islets Yes No
MHC association Yes ?
Treatment? Insulin Diet, exercise, medication
From Dr. Wright’s slide
Vitamin D3 (VD3)Vitamin D3 (VD3)(1, 25-dihydroxyvitamin D3)
-Produce in the skin from sunlight
so, fall VD3 production during winter
-PTH(parathyroid hormone) increase VD3 hormones
-Increase Ca2+ in blood by..... Reabsorption of calcium from intestine
Reabsorption of calcium in kidneysReabsorption CaPO4 crystals of bone
In case of high calcium but normal phosphate VD3 – ↑reabsorption of phosphate and ↑reabsorption of calcium in the kidney.
PTH - ↓↓reabsorption of phosphate and ↑reabsorption of calcium in the kidney.
See table 19.7 Endocrine regulation of Ca and phosphate balance
Designed by Pyeongsug Kim, ©2010
_____-increase resorption in bone. -increase absorption in small intestine.-increase absorption in kidney. therefore, (lower/rise) Ca2+ level in blood.
________- inhibits dissolution of bone- stimulates excretion of Ca2+ in urine therefore, (lower/rise) Ca2+ level in blood.
Calcitonin
PTH
Calcium levels regulated by hormone- ______________
calcitonin & PTH
Designed by Pyeongsug Kim, ©2010
When blood Ca2+ level rises…. When blood Ca2+ level rises….
Negative feedback!
Designed by Pyeongsug Kim, ©2010
When blood Ca2+ level falls…. When blood Ca2+ level falls….
Negative feedback!
Designed by Pyeongsug Kim, ©2010
Consequences of having low blood calciumConsequences of having low blood calcium-Result from inadequate amount of VD3 or low PTH ↓Reabsorption Ca2+ from bone, kidneys, and intestine ↓ Blood Ca2+
Bone demineralization to increase Blood Ca2+
Osteomalacia, Osteoporosis rickets(in children)
Bone demineralization – loss calcium from the boneBone mineralization – deposit calcium into the bone
Designed by Pyeongsug Kim, ©2010