endocrine - pancreas

Question 0

Secreted in equinolar amts as insulin.

Measured in the blood to quantify endogenous insulin production

Answer 0

C-peptide

Question 1

Insulin is catabolic/anabolic

Answer 1

Anabolic

Question 2

Insulin is stored in secretory granules in Zn-bound crystals. It is released by exocytosis of granule contents ff by endocytosis. It has 2 biphasic release

Answer 2

1st (early phase)

2nd (late phase)

Question 3

Biphasic phase of insulin that is short lived and prompt.

Answer 3

1st (early phase )

Question 4

Biphasic phase of insulin that involves release of preformed insulin.

Answer 4

First or early phase

Question 5

Biphasic phase of insulin that is responsible to peak insulin secretion after meal

Answer 5

First or early phase

Question 6

Biphasic phase of insulin that is slower onset and maintained for considerable periods

Answer 6

2nd or late phase

Question 7

Biphasic phase of insulin that involves release of newly formed insulin.

Answer 7

2nd or late phase

Question 8

Peak of first or early phase

Answer 8

5 min

Question 9

Duration of 2nd phase

Answer 9

10 min - 1 hr

Question 10

Half life of insulin

Answer 10

5-8min

Question 11

Insulin is degraded by what enzyme found in liver, kidney and other tissue

Answer 11

Insulinase

Question 12

Insulin is responsible for maintaining the upper limit of blood glucose and FFA by

Answer 12

Promoting glucose uptake and utilization by muscle and adipose tissue
Increase glycogen storage in liver and ms
Decrease glucose output by liver

Question 13

Insulin action

Answer 13

Promotes protein synthesis
Inhibits protein degradation
Ptromotes TGL synthesis 
Inhibits lipolysis 
Has effects on satiety

Question 14

Primary stimulus and regulator of insulin

Answer 14

Glucose

Question 15

Entry kg glucose into B-cells is facilitated by

Answer 15

Glut-2 transporter

Question 16

Glucose is phosphorylated into G6P by what enzyme

Answer 16

Glucokinase

Question 17

Glucose sensor of B cells

Answer 17

Glucokinase

Question 18

Regulation of insulin

Answer 18

Glucose enters Bcells by glut-2 
Glucose to G6P by glucokinase
Send signals to increase ATP/ADP ratio
Closes K channel
Depolarize
Opens Ca channel
CA entry 
Stimulates insulin secretory granule 
Release insulin thru exocytosis

Question 19

Insulin mechanism of action

Answer 19

Insulin binds to IR
Initiates series of phosphorylation reaction and gene expression
Glut-4 transports glucose from outside to inside
Glycogen, lipid and protein synthesis

Question 20

Insulin receptor has a and B subunit. Which subunit is external to cell membrane?

Answer 20

Alpha subunit

Question 21

Insulin receptor has a and B subunit. Which subunit contains hormone binding site?

Answer 21

Alpha subunit

Question 22

Insulin receptor has a and B subunit. Which subunit spans the cell membrane.

Answer 22

Beta subunit

Question 23

Insulin receptor has a and B subunit. Which subunit contains tyrosine kinase on cyto solid surface?

Answer 23

Beta subunit

Question 24

Insulin + receptor results to cross phosphorylation of B subunits leading to recruitment of adaptor proteins such as..

Answer 24

IRS (insulin-receptor substrates)
SHC protein
APS protein

Question 25

IRS phosphorylation leads to activation of..

Answer 25

Protein kinase B (PKB) dependent pathway

Resulting to metabolic effects of insulin.

Question 26

Termination of Insulin/IR signaling

Answer 26

1. Insulin down- regulates own receptor by receptor-mediated endocytosis and degradation pathways
2. Inactivation of IRS protein by serine/threonine protein kinase
3. Activation of “suppressor cytokines signaling” SOCS which reduces acty levels of IR and IRS proteins.

Question 27

Action of insulin

Answer 27

*Glucose uptake (by GLUT-4 availability in ms and fats)
*Glucose use
Glycogenesis
*Glycolysis
Decrease glycogenolysis

Specific in liver
FA synthesis and VLDL
decrease gluconeogenesis 
Decrease x
Decrease urea cycle activity 

Specific in ms
Aa uptake
Protein synthesis
Decrease proteolysis

Specific in adipose tissue
Production of a-glycerol phosphate
Esterification of fats
Decrease lipolysis

Question 28

Insulin is catabolic/anabolic

Answer 28

Catabolic

Question 29

Primary counter regulatory hormone of insulin

Answer 29

Glucagon

Question 30

Glucagon is a primary counter regulatory hormone by

Answer 30

Increase bld glucose thru hepatic glucose output
Increase glucose production thru (increase glycogenolysis, gluconeogenesis, and decrease glycolysis, glycogenesis and inhibits FFA synthesis from glucose)

Question 31

Glucagon circulates in bound/ unbound form

Answer 31

Unbound form

Thus has short half life of 6min

Question 32

Primary site of degradation of glucagon

Answer 32

Liver

80% in single pass

Question 33

Primary target organ of glucagon effect

Answer 33

Liver

Question 34

Determines net flow of hepatic metabolic pathway

Answer 34

Insulin/glucagon ratio

Question 35

Major stimulus of glucagon

Answer 35

Low blood glucose

Question 36

Stimulates glucagon secretion

Answer 36

Low blood glucose
High aa (arginine, alanine)

Sympa NS stimulation (B2 adrenergic)
Stress
Exercise

Question 37

Inhibits glucagon secretion

Answer 37

Somatostatin
Insulin
High blog glucose

Question 38

Somatostatin is also found in

Answer 38

Hypothalamus and GIT

Question 39

Somatostatin has 2 forms

Answer 39

Somatostatin-14

Somatostatin-28

Question 40

Importance of somatostatin is not clearly established but..

Answer 40

It can inhibit insulin and glucagon secretion thru paracrine mechanisms depending in what the body needs

Question 41

Pancreatic polypeptide is stimulated by

Answer 41

Various GIT hormone

Vagal stimulation