lab 2

Fate of absorbed glucose:
  1. Diffusion to blood to increase blood Glucose.
  2. Utilized to generate energy (Kreb’s cycle, Glycolysis).
  3. Stored as glycogen (Glycogenesis).
  4. Biologically important substances: Hexose Monophosphate shunt (HMP) (Ribose, Deoxyribose, NADPH…).
  5. Formation of glucuronic acid (Uronic acid pathway)

[[Blood glucose normal levels[[

fasting levelrandom blood glucosepost-prandial (2 hours after meal) level
at most 150 mg/dl70-110 mg/dl80-120 mg/dl
Blood glucose homeostasis

In case of ==hyperglycaemia==: the body removes/uses up glucose through glycogenesis, lipogenesis, oxidation processes--glycolysis/krebs cycle or HMP.

In ==hypoglycaemia==: glucose is added/increased through diet, glycogenolysis, glyconeogenesis or fructose/galactose breakdown.

Glucose absorption by cells:
]]Facilitated transport.]]]]Active transport/co-transport]]
Down the conc. gradientfrom low conc to high conc.
Does notneedenergynot need energy but requires glucose transporter.needsenergyneeds energy, Na conc gradient and needs glucose carrier.

Regulation of blood glucose levels:

A) Hormonal regulation
  1. Insulin
  • stimulates glucose uptake by cells.
  • inhibits processes that increase glucose.
  1. Anti-insulin hormones
  • glucagon
  • glucocorticoids
  • thyroxine
  • growth hormone
  • E & NA
B) Hepatic regulation

The liver activates or prevents processes that increase blood glucose (glycogenolysis, glyconeogenesis ) or decrease blood glucose (glycogenesis, glycolysis, krebs cycle) according to the body's needs.

C) Renal regulation

Since glucose is freely filtered in kidney, there are glucose reabsorption enzymes that prevent glucose loss in urine (glucosuria)

{{Renal threshold{{ Normal: 180 mg%

A congenital defect could cause low renal threshold (120 mg%), causing glucosuria though normal blood glucose levels (diabetes innocence).

A person with high renal threshold (220 mg%) could have high blood glucose level but no glucosuria as in old age and diabetes.

Types of diabetes

  1. Diabetes mellitus
TYPE 1TYPE 2
Insulin dependent DMInsulin independent DM
Partially genetic--Autoimmune diseaseGenetic
DestructionofB−cellsofLangerhansDestruction of B-cells of LangerhansInsulinresistanceInsulin resistance
Low level of insulinNormal insulin levels
Common ketosis (starvation in midst of plenty)Rare ketosis
generally malnourishedgenerally obese
  1. Diabetes insipidus

Deficiency of antidiuretic hormones (ADH).

  1. Diabetes innocence

Because of low renal threshold

  1. Bronz diabetes

Excessive iron damages liver and pancreas (impaired blood glucose regulation)