diversity of endocrine system

Question 1

Major androgen or androgen precursor produced by adrenal cortex

Answer 1

Dehydroepiandrosterone (DHEA)

Question 2

Most potent adrenal androgen rsults from reduction of androstenedione at C17

Answer 2

Testosterone

Question 3

Which among the following uses CGMP as its second messenger
A. ANP and NO
B. ACTH and calcitonin
C. Adinopectin and EPO
D. Acetylcholine and angiotensin II

Answer 3

A.
B-second messenger is cAMP
C- second messenger is kinase or phosphatase cascade
D.second messenger is calcium or phophatidylinositols

Question 4

Most significant product and active form of testosterone

Answer 4

DHT

Question 5

Primary estrogen of ovarian origin

Answer 5

17 B-Estradiol

Question 6

First step in the amplification of hormonal response

Answer 6

Receptor-effector coupling

Coupling of hormone binding to signal transduction

Question 7

Formed if the substrate of aromatase enzyme complex is testosterone

Answer 7

Estradiol

Question 8

Source of androstenodione and testosterone

Answer 8

Theca cells

Question 9

Progesterone, a precursor for all steroid hormones is produced and secreted by

Answer 9

Corpus luteum

Question 10

Major source of estrogens in postmenopausal woman

Answer 10

Conversion of androstenedione to estrone

Question 11

Which among the following is not involved in the conversion of tyrosine to epinephrine
A. Ring hydroxylayion
B. Decarboxylation
C. Side-chain hydroxylation to form norepinephrine
D, N-methylation to form epimephrine
E. None of the above

Answer 11

E.

Question 12

Rate limiting enzyme for catecholamine biosynthesis

Answer 12

Tyrosine hydroxylase
(Functions as a oxidoreductase with tetrahydropteridine as a cofactor

Question 13

Catalyze the convetsion of dopamine to norepinephrine

Answer 13

Dopamin B-Hydroxylase

Question 14

Precursor of T4 and T3

Answer 14

Thyroglobulin (provides the conformation required for tyrosyl coupling and iodide organification

Question 15

The foloowing is the result of avute decrease Ca2+ concentration
A. Increase PTH mRNA
B. Increase rate of PTH synthesis and secretion
C. All of the above
D. None of the above

Answer 15

C.

Question 16

Supply of T3 and T4 exists in the thyroglobulin that is stored where?

Answer 16

Stored in colloid in the lumen of thyroid follicle (released upon stimulation by TSH)

Question 17

Which of the following hormones has no intracellular resorvoir because they are secreted as they are made
A. T3 and T4
B. Insulin
C. Steroids and 1,25(OH)2D
D. Catecholamines and PTH

Answer 17

C.
A.stored for weeks
B. Stored for days
D. Stored for hours

Question 18

Most of T3 and T4 is bound to

Answer 18

Thyroxine-binding globulin
Hormones when bound cannit be metabolized prolonging their half life.
T4 is more bound that T3

Question 19

Main plasma binding protein of hydrocortisone is an a-globulin called

Answer 19

Transcortin or corticosteroid-binding globulin

Synthesis is incrased by estrogen

Question 20

Estrogen is bound yo sex-hormone-binding protein while progestins is to

Answer 20

Coryicosteroid binding protein

Question 21

Insulin is bound to 
A.cGMP
B.cAMP
c. Calcium
D. Protein kinase

Answer 21

D.

Insulin uses tyrosine kinase

Question 22

Cyclic AMP is a nucleotide generated from ATP through the action of

Answer 22

Adenylate cyclase

Question 23

Which among the following is synthesized from cholesterol
A. Catecholamines
B. Peptides
C. Adrenal steroid
D. Glycoproteins

Answer 23

C

A. Derived from tyrosine

Question 24

Which among the following secondary messenger releases calcium
A.IP2
B. IP3
C. DAG
D. Tyrosine

Answer 24

B.

C-activates protein kinase

Question 25

``` Which among the following is not an amino acid derivative hormone A.epinephrine B.serotonin C.glutamic acid D.leptin ```

Answer 25

D.it is from peptides and proteins

Question 26

Rate limiting step for steroid hormones is conversion of cholesterol to

Answer 26

Pregnenolone

Question 27

Which among the following hormones is not a principal class of fatty acidsA.leukotrienes B.thromboxane C.prostaglandin D.histamine

Answer 27

D. Amino acid derivative

Question 28

Other term for Growth hormone releasing factor

Answer 28

Somatocrinin | In arcuate nucleus of hypothalamaus

Question 29

Inhibits growth hormones by hyperpolarizing the somatotropes

Answer 29

Somatostatin

Question 30

More potent inhibitor of growth hormone, glucagon and insulin than the natural hormone

Answer 30

Octreotide

Question 31

Synthesized by the placenta and seems to determine the duratiom of pregnanacy; released during stress response

Answer 31

Corticotropin releasing hormone

Question 32

Tripeptide hormone that stimulate release of thyroid stimulating hormone and prolactin buy the anterior pituitary

Answer 32

Thyrotropin releasing hormone

Question 33

A peptide hormone responsible for the release of FSH and LH from the anterior pituitary

Answer 33

Gonadotropin Releasing hormone 1

Question 34

Inhibit prolacyin release

Answer 34

Dopamine

Question 35

Which among the following have a normal or excess plasma GH, but lack liver GH receptors and have low levels of circulating IGF-1 A. Laron dwarfs B. Pygmies C. GH hormone degicient dwarfs

Answer 35

A

Question 36

Pituitary secretion is regukated and inhibited by

Answer 36

Dopamine neurons

Question 37

Structure and fuction same as growth hormone; has anti insulin property

Answer 37

HPL/CS

Question 38

In men, FSH enhances the production of androgen binding protein by the Sertoli cells of the testes and critical for

Answer 38

Spermatogenesis

Question 39

Prevent the disintegration of the corpuse luteum maintain progesterone production

Answer 39

HCG

Question 40

Mimic LH and helps restore and maintain testosterone production in the testes

Answer 40

hCG | In male-hcg injections are used to stimulate the leydig cells to synthesize testosterone

Question 41

What disease is caused by stimulating antibodies (Thyroid stimulating autoantibodies) to the TSH receptor and mimic TSH action by increasing intracelluar cAMP

Answer 41

Graves disease

Question 42

Oveproductoon of ACTH results in

Answer 42

Cushing syndrome | Results in Na, K, and P negative balance

Question 43

Gives the feeling of euphoria

Answer 43

Endorphins

Question 44

Which among the following differentvreceptos of the vasopressin causes corticotropin secretion from pituitary gland A.V2 B. VIA C.VIB

Answer 44

C A-free water reabsorption B-vasoconstriction,gluconeogenesis, platelwt aggregation, relese factor 8

Question 45

In thr follicular lumen, iodide is oxidized by an enzyme found only in thyroid tissue called

Answer 45

Thyroperoxidase

Question 46

Degrade the thyroglobulin releasing amino acids T3 and T4, which are secreted into the circulation

Answer 46

Lysosomal proteases

Question 47

Thryoxine-binding globulin prealbukin is also responsible for the transport of

Answer 47

Retinol-transthyretin (TTR)

Question 48

80% of circulating T4 is converted to T3. This conversion is inhibited by

Answer 48

PTU and propanolol

Question 49

Which among the following is not the action of thyroid hormones A. Increase metabolic rate B. Protein synthesis C. Increase the body's insensitivity to catecholamines D. Regulate protein, fat and carbohydrate metabolism

Answer 49

C

Question 50

The immediate precursor of PTH which has a highly basic hexapeptide amino terminal extension

Answer 50

proPTH

Question 51

Which among the ff is not true A.PTH increases reabsorption of phosphate in tge kidneys to decrease its excretion B.PTh reduces renal Ca2+ clearance C. PTH increase Ca2+ levels in ECF D. PTH acts by binding to cAMP-coupled plasma membrane receptors

Answer 51

A

Question 52

Responsible for Ca2+ reabsorption in the intestine; most potent naturally occuring metabolite of vitamin D

Answer 52

Calcitriol

Question 53

Where in the body does Vit D is produced during photolysis reaction using 7-dehrydrocholesterol A liver B skin C kidney

Answer 53

B. A. Undergoes hydroxylation in endoplasmic reticulum by 24-hydroxylase C. Monohydroxy D3 from the liver is converted to its active form by hydroxylation at position C1 by 1a-hydroxylase

Question 54

Which among the following is nod needed in the activation of Vit D A.CP450 B. Iron sulfur protein, renal ferredoxin C. Flavoprotein, renal ferredoxin reductase D. Flavoprotein, renal ferredoxin synthase

Answer 54

D.

Question 55

Has the counter effects of parathyroid hormones and reduce synthesis of osteoporin and regulates Vitamin D.

Answer 55

Calcitonin