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Biology for Secondary Schools
distinct parts: the anterior pituitary and the
posterior pituitary. Despite its small size,
the pituitary gland has a major influence
on growth, metabolism, reproduction, and
homeostasis in the body.
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Anterior pituitary hormones
The anterior pituitary, which makes up
the front portion of the pituitary gland,
produces and secretes several important (b) Growth Hormone (GH): Growth
hormones that regulate various body
functions. These hormones can be grouped
into several categories:
(a) Tropic hormones: These are hormones
that regulate the activity of other
endocrine glands. They include the
following:
(i) Thyroid-Stimulating Hormone
(TSH): This hormone stimulates the
thyroid gland to produce and release
thyroid hormones, which are crucial
for regulating metabolism, energy (c) Prolactin (PRL): Prolactin plays a
production, and overall growth.
(ii) Adrenocorticotropic Hormone
(ACTH): ACTH stimulates the adrenal
cortex (part of the adrenal glands) to
produce cortisol, a hormone involved
in stress responses, metabolism, and
immune system regulation.
(iii) Follicle-Stimulating Hormone (FSH):
FSH is involved in the regulation of
the reproductive system. In females,
it stimulates the growth of ovarian
follicles and the production of eggs,
while in males, it stimulates sperm (d) Melanocyte Stimulating hormone
production.
(iv) Luteinizing Hormone (LH): LH
works alongside FSH to regulate
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BIOLOGY FORM 3 FINAL EDITED 16.09.2025.indd 68 KAMISHNA
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the menstrual cycle in females. It
triggers ovulation (the release of
an egg from the ovary) and helps
with the production of estrogen and
progesterone. In males, it stimulates
the production of testosterone in
the testes. Follicle stimullating
hormones and luteinizing hormones
are collectively called gonadotropins.
hormone, also known as somatotropin,
is one of the most important hormones
produced by the anterior pituitary. It
stimulates growth, particularly in bones
and muscles, and regulates metabolism.
GH promotes protein synthesis,
increases the breakdown of fats, and
ensures that energy is available for
growth and development. An imbalance
in GH can result in conditions like
gigantism or dwarfism.
crucial role in reproductive health,
particularly in females. Its primary
function is to stimulate milk production
in the mammary glands after childbirth.
While it is often associated with
lactation, prolactin also has roles in
immune function and the regulation of
the menstrual cycle. Elevated levels of
prolactin, in the absence of pregnancy,
can cause infertility and disrupt the
normal functioning of the reproductive
system.
(MSH): It is involved in the stimulation
of the production of melanin for skin
and hair.
Student’s Book - Form Three
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