Chapter 9 ( Hormones )

Question 1

Types of hormones according to site of action ?

Answer 1

1- Paracrine hormones : Prostaglandins and Neurotransmitters , they are secreted into interstitial space and have very short half-life
2-Telecrine hormones : Endocrine and Gastrointestinal hormones , they are secreted into bloodstream and generally have longer half-life

Question 2

Example for water-soluble hormones and lipid-soluble hormones ?

Answer 2

Water-soluble hormones : 
Insulin 
Glucagon
Catecholamines 
Lipid-soluble hormones : 
Steroids 
Calcitriol 
Thyroxines
Retinoic acid

Question 3

E-coli heatstable toxin mechanism ?

Answer 3

Binds to and stimulates guanylate cyclase incresing cGMP , this cause increased activity of CFTR and diarrhea

Question 4

Phosphatidylinositol-3-kinase function ?

Answer 4

Translocation of GLUT4 to membrane in adipose tissue and muscles

Question 5

Trimeric G proteins ?

Answer 5

Gs , Gi , Gq , Gt

Question 6

Monomeric G protein example ?

Answer 6

p21ras G protein

Question 7

Cholera toxin and E-coli heat labile toxins mechanism ?

Answer 7

ADP ribosylation of Gs alpha leading to an increase in cAMP and subsequently chloride secretion from intestinal mucosal cells and causing diarrhea of cholera

Question 8

Pertussis toxin mechanism ?

Answer 8

ADP ribosylation of Gi alpha which dramatically reduces its responsiveness to the receptor which leads to increase in cAMP

Question 9

SH2 domains function ?

Answer 9

Transmit signals from a tyrosine kinase receptor

Question 10

Examples for vasodilators which increase nitric oxide synthase activity ?

Answer 10

Acetylcholine
Bradykinin
Histamine
Serotonin

Question 11

Hormones that act through the cAMP pathway ?

Answer 11

Glucagon
Epinephrine Beta , Alpha2
Vasopressin ( V3 , ADH )
Kidney

Question 12

Hormones that act through PIP2 pathway ?

Answer 12

Epinephrine Alpha1
Vasopressin ( V1 , V3 )
Vascular smooth muscle