PHC 801-Oxytocin and Vasopressin - Prof. T. O. Idowu.ppt

Advanced chemistry of Oxytocin and Vasopressin for undergraduates, postgraduates and researchers

1. Oxytocin
and vasopressin

2. General introduction
The pituitary gland is
a
small
pea-
sized gland that
plays a
major
role.It is referred
to
as the body's
'master gland'
because
it
controls the activity of
most
other hormone-
secreting glands

3. Cont;
•Oxytocin is secreted mainly by paraventricular nucleus and
supraoptic nuclei.
•Transported from hypothalamus to posterior pituitary
through nerve fiber of hypothalamus hypophyseal tract.
•It stores in nerve endings.
•When stimuli reach the posterior pituitary from
hypothalamus oxytocin is released in blood
•Secreted in both males and females.
•Can not re-enter in to brain because it can not cross blood
brain barrier.

4. Action
(in females)
On mammary glands:
1.Cause
ejection of milk from mammary glands.
2.Cause
contraction of myoepithilial cells and flow of milk
from
alveoli of mammary glands to the exterior through
duct
system.
3.The
process by which milk is ejected from alveoli is
called
milk ejection reflex.(one of neuro endocrine
reflexes).
On uterus:
It
affects differently on pregnant uterus and on non
pregnant
uterus.

6. Cont;
On pregnant uterus:
1.Throughout
the period of pregnancy oxytocin
secretion
is inhibited by both estrogen and
progesterone.
2.At
the end of pregnancy the secretions of both
hormones
is decreased and suddenly the secretion of
oxytocin
increases.
3.It
cause contraction of uterus and help in expulsion of
fetus
by positive feedback reflex.
On non pregnant uterus:
1.It
facilitate the transport of sperms from the female
genital
tract to fallopian tubes by producing uterine
contraction
during the sexual intercourse.

7. Action
(in males)
In
males release of oxytocin increase during
ejaculation.
It
facilitates release of sperms in to urethra by
causing
contraction of smooth muscle fibers in
reproductive
tract.

8. Oxytocin
(the multitasking love hormone)
Oxytocin
is a peptide hormone
and
neuropeptide having 9 amino
acids.
.
It plays a role in social bonding,
sexual
reproduction, childbirth,
and
the period after childbirth
 The
sequence is cysteine -
tyrosine
- isoleucine - glutamine -
asparagine
- cysteine - proline -
leucine
- glycine
 The
cysteine residues form a
sulfur
bridge

9. oxytocin

10. Chemistry and structure:
Molar
mass
:
 
1,007.19 g/mol
Formula:
 
C
43H
66N
12O
12S
2
Excretion:
 
Biliary
and kidney
Source
tissues
:
 
pituitary gland
Elimination half-life:
 
1–6
min (IV); ~2 h (intranasal)

11. Oxytocin
binds to oxytocin receptors in the uterine myometrium, which
triggers
the G-protein coupled receptor signal transduction cascade that
causes
increased intracellular calcium concentrations.
 Increased calcium concentration
levels activate myosin light chain kinase
which,
in turn, induces the formation of the contractile protein actomyosin.
 This
stimulates uterine smooth muscle contractions.
This
agent also stimulates smooth muscles in the mammary glands, thereby
causing
lactation.

12. Adverse effects:
Oxytocin
is relatively safe when used at recommended
doses.
Potential side effects include:
Central nervous system:
Subarachnoid hemorrhage,
seizures;
 Cardiovascular:
Increased heart rate, blood
pressure,
systemic venous return, cardiac output, and
arrhythmias

Genitourinary:
Impaired uterine blood flow, pelvic
hematoma,
tetanic uterine contractions, uterine
rupture,
postpartum hemorrhage

13. Brand names
Pitocin

Syntocin

Oxytocin

Oxyton

14. Vasopressin
Secreted
mainly by supraoptic
and
paraventicular nucleus in
small
quantity.
From
here transported to
posterior
pituitary through the
nerve
fiber of hypothalamus
hypophyseal
tract by means of
axonic
flow.

15. Actions
Retention of water:(on kidneys)
Antidiuretic
hormone stimulates water reabsorption by
stimulating insertion of
"water channels" or aquaporin's
into
the membranes of kidney tubules.
 These
channels transport solute-free water through
tubular
cells and back into blood, leading to a decrease
in
plasma osmolality and an increase osmolality of urine.

16. Cont;

17. Cont;

18. Cont;
Vasopressor action:(on vascular system)

19. Cont;

20. Mode of action:

21. Vasopressin is
a peptide hormone.
The
vasopressins are peptides consisting of nine amino
acids
(nonapeptides).
The
amino acid sequence of arginine vasopressin is
Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly,
with the cysteine
residues
forming a sulfur bridge.
Vasopressin,
also called
antidiuretic hormone,
arginine
vasopressin
or argipressin, is a hormone synthesized as
a
peptide prohormone in neurons in the hypothalamus,
and
is converted to AVP. 
Vasopressin

22. Chemical structure
Protein binding:
 
1%
Formula:
 
C
46H
65N
15O
12S
2
Molar mass:
 
1084.24
g·mol
−1
Receptors:
 
V
1A
,
V
1B
,
V
2
,
OXTR
Target tissues:
 
System-wide
Other names:
 
Antidiuretic
hormone (ADH); arginine
vasopressin;
argipressin
Half life:
18-20 mins

23. Brand names photo
Desmopressin

pitressin
vasostrict

24. Nanopeptide nucleus

25. ******************/////==--
0099888776654321`q

26. SAR
Oxytocin
is a peptide of nine amino acids (a
nonapeptide).
The sequence is cysteine - tyrosine -
isoleucine
- glutamine - asparagine - cysteine - proline -
leucine
- glycine (CYIQNCPLG). The cysteine residues
form
a sulfur bridge. Oxytocin has a molecular mass of
1007
daltons. One international unit (IU) of oxytocin is
the
equivalent of about 2 micrograms of pure peptide.
The
structure of oxytocin is very similar to that of
vasopressin
(cysteine - tyrosine - phenylalanine -
glutamine
- asparagine - cysteine - proline - arginine -
glycine),
also a nonapeptide with a sulfur bridge, whose
sequence
differs from oxytocin by 2 amino acids

28. Research on oxytocin
Oxytocin
increase trust in human
Trust
pervades human societies. Trust is indispensable in
friendship,
love, families and organizations, and plays a key role
in
economic exchange and politics
.
.
In the absence of trust
among
trading partners, market transactions break down.
https://www.nature.com/articles/nature03701

29. Research on vasopressin
vasopressin
has been a hot topic in a very different
field:
social behavior. And recently it has emerged as
a
possible target for treating autism spectrum
disorders
(ASD), which are characterized by social,
behavioral
and communication impairments.
https://www.scientificamerican.com/article/vasopressin-
emerges-as-hormone-of-interest-in-autism-research/