Pharmacology of Posterior Pituitary Hormones Flashcards Preview

Pharmacology Test #5 > Pharmacology of Posterior Pituitary Hormones > Flashcards

Flashcards in Pharmacology of Posterior Pituitary Hormones Deck (29)
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1

Oxytocin preparations

Pitocin, Syntocinon

2

Vasopressin Agonists

1. Vasopressin (Pitressin)
2. Desmopressin Acetate (DDAVP, Minirin, Stimate)

3

Vasopressin Antagonists

1. Conivaptan HCl (Vaprisol)
2. Tolvaptan (Samsca)
3. Demeclocycline (Declomycin, Declostatin, Ledermycin)

4

Where is ADH/Vasopressin synthesized?

synthesized in the supraoptic and paraventricular nuclei of the hypothalamus and transported down axons to the posterior pituitary

5

Control of ADH secretion

stimulus for secretion is an increase in plasma osmolality above the normal set point

6

Summary of stimuli for ADH secretion

pain, nausea, hypoxia, chronic disease states in which effective circulating volume is reduced

7

ADH release can be reduced by

decrease in plasma osmolality; increase in blood volume; alcohol; nicotine; emotional stress

8

Hormones/NT that stimulate ADH secretion

ACTH; histamine; dopamine; glutamine; aspartate; cholecystokinin; substance P; VIP; prostaglandins; Angiotensin II

9

Hormones/NT that inhibit ADH secretion

atrial natriuretic factor; GABA; opioids

10

Water balance abnormalities can be caused by

Genetic diseases; acquired diseases; pharmaceutical agents

11

Nephrogenic diabetes insipidus is due to

lack of response of kidney collecting tubule cells to ADh stimulations

12

SIADH

excessive ADH production which causes the retention of water resulting in the decrease of effective concentrations of solutes such as sodium

13

Actions of ADH on the kidney

enhance absorption of water from collecting tubule of nephron; acts on the basolateral surface of cells in the cortical and medullary portions of the collecting tubule

14

Other renal sites of ADH actions

glomerular reduction in ultrafiltration; stimulates active reabsorption of NaCl by cells in the medullary thick ascending limbs (osmotic gradient is magnified)

15

V1 receptors mediate

pressor effects - lower affinity for ADH; coupled to phospholipase C

16

V2 receptors mediate

antidiuretic effects - high affinity for ADH; coupled to adenylate cyclase

17

What happens with ADH stimulation of V2 receptors?

aquaporin water channels become inserted into the luminal membrane and the rate of removal of water channels is reduced

18

Prostaglandins (especially PGE) inhibit

antidiuretic action of ADH

19

Lithium inhibits

actions of ADH by inhibiting cAMP production via V2 receptors

20

Demeclocycline inhibits

ADH action through attenuation of cAMP production

21

Demopressin only has what kind of effect?

only antidiuretic effect (little to no pressor effect)

22

Uses of Vaopressin/ADH

1. treatment of neurogenic diabetes insipidus
2. treat esophageal variceal bleeding and colonic diverticular bleeding

23

Toxicity and contraindications of ADH treatment

overdose may result in hyponatremia and seizures; vasopressin (not desmopressin) can cause vasoconstriction so it must be used with caution in patients with CAD

24

Vasopressin receptor antagonists are known as

aquaretics; useful in the treatment of SIADH

25

Tolvaptan has a high affinity for which receptor

high affinity for V2 more than V1

26

Where is oxytocin synthesized?

in the supraoptic and paraventricular nuclei of the hypothalamus

27

Clinical uses of oxytocin

used to induce labor, augment dysfunctional and protracted labor, manage uterine atony or uterine hemorrhage, induce contraction during surgery, in "oxytocin challenge test"

28

Contraindications for oxytocin

fetal distress or abnormal fetal presentation; predisposition for uterine rupture

29

Oxytocin receptor antagonist

Atosiban (Tractocile, Antocin)