neurotransmitters

1. Testosterone, Cortisol, Oxytocin, HPA and HPG axis.

2. INTRODUCTION
• Cortisol is released from adrenal cortex and plays a role in
stress.
• Testosterone is released from gonads and is related to
aggression.
• Testosterone and cortisol have their parts to play in the Dual
Hormone Hypothesis.
• Oxytocin is released from the posterior pituitary gland and is
famously called the love hormone.

3. TESTOSTERONE
• It is a steroid hormone from the androgen
group.
• Key role- in the development of male
reproductive tissues (testis, prostate) as well
as promoting secondary sexual characteristics
–increased muscle, bone mass etc .
• Plays a role in aggression and dominance.
• Helps to spark competitiveness and boost self-
esteem.

4. Dual Hormone Hypothesis
• The dual hormone hypothesis posits that basal cortisol and testosterone
have a joint effect on motivational and behavioral systems implicated in
dominance and aggression, such that traits generally associated with high
testosterone manifest more in individuals with low basal cortisol levels.
• Because dominance is related to gaining and maintaining high status
positions in social hierarchies, the findings suggest that only when cortisol is
low should higher testosterone encourage higher status. When cortisol is
high, higher testosterone may actually decrease dominance and in turn
motivate lower status.

5. CORTISOL
• Cortisol is a glucocorticoid hormone synthesized from the middle
area of the adrenal cortex within the adrenal gland.
• It is released in response to stress and low blood glucose
• While cortisol’s primary targets are metabolic, it also affects ion
transport, the immune response, increase blood
sugar through glucogenesis.
• Sleep deprivation can cause cortisol levels to increase by over 50%. It
causes the depletion of neurotransmitters, mood regulating
hormones, and this has the effect of making people more vulnerable
to becoming easily depressed. Impaired cognitive ability, out of check
emotions, and poor judgment or poor logic also results from sleep
deprivation.

7. CERTAIN FACTS ON CORTISOL
• Prolonged exposure to high cortisol levels can lead to break down of muscle,
excessive epinephrine release, hyperglycemia, weakening of bone, destruction of
the immune system, inhibition of reproductive function, and other complications.
• Expressed at the highest levels in the early morning, cortisol’s main function is to
restore homeostasis following exposure to stress The effects of cortisol are felt
over virtually the entire body and impact several homeostatic mechanisms.
• Cortisol works with epinephrine (adrenaline) to create memories of short-term
emotional events; The hippocampus, the region of the brain where memories are
processed and stored, contains many cortisol receptors. While normal cortisol
levels have no adverse effects on the hippocampus, excess cortisol overwhelms
the hippocampus and actually causes atrophy However, long-term exposure to
cortisol damages cells in the hippocampus this damage results in impaired
learning. Furthermore, it has been shown that cortisol inhibits memory retrieval
of already stored information.

8. OXYTOCIN
• It is a neuromodulator.
• It is produced in supraoptic and paraventricular
nuclei of the hypothalamus by the nerve axons and
stored in the posterior pituitary gland.
• It is a peptide of nine amino acids.
Functions:
• The letdown reflex
• Uterine contraction
• Social behaviour and wound healing
• Modulation of HPA axis activity
• Interaction of vasopressin.

11. Facts Emphasizing Oxytocin
• Dopamine and oxytocin receptors produce a
euphoria like state that may account for “love at
first sight” phenomenon.
• Oxytocin have been found to be related to trust
(not alone romantic but also business and
occupational)
• Holding grudge produces cortisol and diminishes
oxytocin
• After being called the love hormone, the trust
hormone, the cuddle hormone, a 2009 study
finds oxytocin associated to envy and jealousy

12. WHAT IS HPA AXIS?
• HPA is also known as Limbic-Hypothalamic-
Pituitary-Adrenal-Axis.
• HPA Axis is a complex set of direct influences and
feedback among the hypothalamus, the pituitary
and the adrenal glands.

13. •The A stands for the adrenal glands. We each have two of
them located just above the kidneys. Although physically
separate from the hypothalamus and pituitary glands, they
are deeply connected.
•Function-The adrenals produce even more hormones
than the pituitary gland does – steroid hormones like
cortisol, sex hormones like DHEA
(Dehydroepiandrostenedione),&stress hormones like
adrenaline and dopamine. The hormones produced by the
adrenals control chemical reactions over large parts of our
bodies, (‘fight-or-flight’ response).
•The H in HPA stands for
Hypothalamus, a small part
of the brain that has
important roles.
•Function-is to send
messages from the brain to
the adrenals,the pituitary
and other organs, so it is
usually considered to be the
starting point in the HPA axis.
•It is ultimately responsible
for things like your circadian
rhythm, your body
temperature and your
energy levels.
•The P stands for the pituitary
gland is a pea sized gland but it
produces an extraordinary
number of hormones that our
bodies need.
•Function-produces vital
hormones like Growth
Hormone, Anti-Diuretic
Hormone and Luteinizing
Hormone. It is physically
connected to the
hypothalamus and is located at
the base of the brain.
HPA Axis
HPA AXIS

15. What is HPG Axis?
 The Hypothalamic–Pituitary–Gonadal axis (HPG axis)
refers to the effects of the Hypothalamus, Pituitary
glands and Gonads.
 The HPG axis comprises of the interaction between
the hypothalamus, pituitary gland and the gonads.
The system works together to regulate development,
reproduction, ageing and many other body
processes. It’s regulation relies upon a number of
complex negative feedback loops which when lost
result in disease.

16. HPG Axis
HYPOTHALAMUS
Gonadotropin-
releasing hormone
(GnRH) is secreted
by GnRH-expressing
neurons.
Gonads
estrogen and
testosterone.
Anterior portion of
the PITUITARY
luteinizing hormone
(LH) and follicle-
stimulating
hormone (FSH)
HYPOTHALAMUS
Gonadotropin-
releasing hormone
(GnRH) is secreted
by GnRH-expressing
neurons.
Anterior portion of
the PITUITARY
luteinizing hormone
(LH) and follicle-
stimulating
hormone (FSH)

17. MALE HPG AXIS

18. FEMALE HPG AXIS

19. Interaction between HPG &HPA axes

21. THANKYOU!