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Biochemistry for Medics

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Blood Glucose Homeostasis

Presented by 001

ABDUL ArShAd

BIOCHEMISTRY

Table of contents•Overview•Regulation of blood glucose•Hormonal control of blood glucose•Hypoglycemia and its clinical aspect•Hyperglycemia and its clinical aspect•Summary

OVERVIEW

Blood Glucose

(60mg-100mg/dl)

Gluconeogenesis

DIET

Hepatic glycogenolysis

Peripheral uptake

utilisation

GLUCOSE OBTAINED FROM OTHER

CARBOHYDRATES

Glycolysis

lipogenesis

glycogenesis

Uronic acid pathway

HMP pathway

Urine(glycosuria)

Other sugars

As blood glucose level tends to increase

Insulin is secreted

Has a hypoglycemic effect

Inhibit pouring of glucose into blood

And promotes utilisation of glucose

As blood glucose level tends to decrease

Decrease insulin secretion

Hormones like : Glucagon, Catecholamines, Growth hormones, glucocorticoids, Thyroid hormones, ACTH

Reverse of insulin and are thus called counter regulatory hormones

In cases of hypoglycemia

Inhibition of insulin(1st line of defence)

Increase realease of glucagon (2nd line of defense)

Realease of catecholamines , anteriour pituitary hormones .ACTH….(3rd line of defense)

Thyroid hormones and growth hormones are not essential for maintanance of blood glucose concetration but have an impact on carbohydrate metabolism

Hormonal control on Blood Glucose

Insulin

Glucagon

Catecholamines

Glucocorticoids

Growth

hormone

Thyroid hormon

es

Absorbtion of glucose

Peripheral uptake

Glycolysis

Gluconeogenesis

glycogenesis

Glucogenolysis

Lipogenesis

Lipolysis

Protein catabolism

Net effect on blood glucose

Tug of war between Insulin & other hormones

INSULIN glucagon

glucocorticoids

G.H

Thyroid hormones

epinephrine

catecholamine

s

Blood glucose concentration

Varitions in blood glucose

Hypoglycemia

(<60mg/dl)

Normal

(60-110mg/dl)

Hyperglycemia

(>110mg/dl)

Hypoglycemia

Low bloood glucose

CNS symptoms

Improvement of symptoms upon glucose adminis tration

Glucose

These 3 is called whipple’s triad

Types of hypoglycemia Hypoglycem

ia

Post parandialHypoglycemia

(PPH)

FastingHypoglycemia

(FH)

Insulin induced hypoglycemiaObserved in Type 1 diabetic patient on insulin

therapy.Overdose of insulin can produce hypoglycemia

Observed in insulinoma and other tumours which cause increase abnormal secretion of insulin

Reactive hypoglycemia-PPH-occurs withing 2hrs of food intake, due to sudden realease of insulin

Leucine induced hypoglycemia-in certain individuals a protein rich diet containing leucine may cause sudden realease of insulin causing hypoglycemia

Alchohol induced hypoglycemia

Observed in chronic alchoholics who are also malnourished

Also precipitated by simultaneous administration of insulin

So patients with type 1 diabetes are give a warning not to consume alchohol

Alchohol

Alchohol dehydrogenase

NAD+

NADH+H++

lactate

pyruvate

acetaldehyde

acetate

Acetaldehyde dehydrogenase NADH+

H++

NAD+ malate

OAA

Acetyl CoA

Inhibition of gluconeogenesis

Hypoglycemia

Pregnancy induced Hypoglycemia

Due to imbalance between demand and supply

NEONATAL HYPOGLYCEMIA

Endocrinal disorders

HYPOTHYROIDISM

HYPOPITUITARISM

HYPOCORTICISM

LIVER DISORDERS

GLYCOGEN STORAGE DISEASES

HEAVY EXERCISE

Click icon to add pictureClick icon to add picture

Click icon to add pictureClinical Manifestations

Neuroglycopenic

Adrenergic

Neuroglycopenic

Confusion

Head ache

Convulsions

Syncopial attacks

Coma and death(untreated)

These are due to deprivation of glucose to

brain cells

Adrenergic

Palpitations

Tremors

Excessive sweating

These are due to realease of

catecholamines especially adrenaline

Always associated

with tachycardia

Lab DiagnosisBlood glucose is low

Plasma insulin high

Endocrinal and liver disorder suspected

TreatmentOral glucose administration if

person is alert

Intravenous glucose administration in unconscious patients

Treat primary cause

Hyperglycemia

Characterised by high blood glucose

Most common cause is diabetes mellitus

Up to 500 mg% or even more

Click icon to add pictureCauses

Click icon to add pictureClick icon to add pictureEndocrinal Non - endocrinal

EndocrinalDiabetese melitus

Hyperthyroidism

Hyperpituitarism

Hypercorticism

hyperadrenalism

Pancreatic disorder

Pancreatectomy

Pancreatitis

Cystic fibrosis Haemochromatosis

Drug induced

Corticosteroids

Thiazide diuretics

High dose of niacin

Phenytoin

InfectionsRubella

Intracranial infections

Sepsis

Exposure to anaesthesia

Intra cranial tumours

DiagnosisMade from clinical symptoms

Blood glucose estimation

Know primary cause of hyper glycemia

TreatmentBase on treating primary

cause

Lowering of blood glucose by either insulin supplimentation or oral hypoglycemic drugs

summary

Bibliography

Biochemistry class notes (DR. Namrata)

Internet

Respected teachers of bichemistry department

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