Hormones of Pituitary Gland

1. THE PITUITARY
GLAND

2. INTRODUCTION
• The pituitary gland or
Hypophysis Cerebri is an
ovoid structure of about
0.5 gm in adults.
• It is connected to the
brain through a stalk
called Infundibulum.
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3. Division in Two Lobes
• The pituitary is
divided into two
lobes.
• The anterior
Pituitary.
• The Posterior
Pituitary.
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4. The Anterior Pituitary
• Hypothalamus (a region of brain) controls
the anterior pituitary by producing:
• The Releasing Hormone:
Stimulates the release of pituitary hormones.
• The Inhibiting Hormone:
Inhibits the release of pituitary hormones.
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5. Releasing & Inhibiting Hormones
• RH and IH are produced in
the cell bodies of
neurosecretory neurons.
• They are stored in the ends
of the axons(present just
above the pituitary) until
needed.
• When released, the
hormones diffuse into
capillaries draining into veins
which in turn drain into
capillaries of pituitary.
• They then bind to the target
cells causing them to release
hormones.
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6. Hormone Major target organ(s) Major Physiologic Effects
Liver, adipose Promotes growth (indirectly), control of protein,
Growth hormone tissue lipid and carbohydrate metabolism
Thyroid-stimulating
Thyroid gland Stimulates secretion of thyroid hormones
hormone
Adrenal gland
Adrenocorticotr (cortex)
Stimulates secretion of glucocorticoids
Anterior opic hormone
Pituitary
Prolactin Mammary gland Milk production
Luteinizing
Ovary and testis Control of reproductive function
hormone
Ovary and testis Control of reproductive function
Follicle-stimulating hormone
Antidiuretic
Kidney Conservation of body water
hormone
Posterior
Pituitary
Stimulates milk ejection and uterine
Oxytocin Ovary and testis
contractions
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7. THE GROWTH HORMONE
• Protein hormone produced by anterior
pituitary under the control of
hypothalamus.
• Production through negative feedback
mechanism.
• The quantity is greatest during
childhood and adolescence.
• The highest blood levels are during
sleep and strenous exercise.
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8. ACTION 0f GH
• GH stimulates growth in the body by
promoting:
• Cellular Enlargement – Hypertrophy.
and
• Increase in the number of cells through
division – Hyperplasia.
• It acts primarily on bones and muscles.
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9. ACTION 0f GH
• In Bones:
It stimulates cell division and protein
synthesis resulting in an increase in the
length and width of bones.
• In Muscles:
It increases uptake of amino acids and
synthesis of proteins.
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10. EFFECTS 0f GH
• DAWARFISM
- Under-secretion
during growth
phase of a child is
one cause of
stunted growth.
- Characterized by
small stature.
- World’s smallest girl due to
Dawarfism. (weighed 2 lbs,
8 ounces when she was
born)
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11. EFFECTS 0f GH
• GIGANTISM:
- Over-secretion
during growth
phase results in
gigantism.
- Giants usually have
poor health.
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12. EFFECTS 0f GH
• ACROMAGELY:
- Over-secretion
after growth phase
results in
acromagely.
- Feets, hands
and face become
overly large.
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13. References
• Human Biology , Daniel D. Chiras ,
Sixth Edition.
• Human Biology , Sylvia S.Madar ,
Magraw Hill , International Eleventh
Edition.
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