The anterior pituitary gland, also called the adenohypophysis, is divided into two parts: the pars anterior and the tiny pars intermedia. The pars anterior contains five major cell types that secrete different hormones: somatotrophs secrete growth hormone, corticotrophs secrete ACTH, thyrotrophs secrete TSH, lactotrophs secrete prolactin, and gonadotrophs secrete LH and FSH. The hypothalamus controls hormone secretion in the anterior pituitary through releasing and inhibiting hormones that travel via the hypophyseal portal system and stimulate or suppress hormone production.

1. ADENOHYPOPHYSIS
M.Rajkumar.M.sc,M.Phil

2. Adenohypophysis, the anterior portion of the pituitary gland,
divided into two parts – the pars anterior and the pars
intermermeda – The pars anterior forms the major portion of
the adenohyphysis and is divided from the tiny pars
intermedia by a narrow left and some connective tissue.
Somatotrophs – secrete growth hormone (GH)
Corticotrophs – Secrete adrenocortiocotropic hormone
(ACTH)
Thyrotrophs – secrete thyroid-stimulating hormone (TSH)
Lactotrophs – secrete prolactin (PRL)
Gonadotrophs – secrete luteinizing hormone (LH) and
follicle – stimulating hormone (FSH)
ADENOHYPOPHYSIS

3. GROWTH HORMONE
Growth hormone (GH), or sometotropin (STH), is thought
to promote bodily growth indirectly by stimulating the liver
to produce certain growth factors, which, in turn, accelerate
amino acid transport into cells. Rapid entrance of amino
acids from the blood into the cells allows protein anbolism
within the cells to accelerate. Increased protein anabolism
allows an increased rate of growth. GH promotes the
growth of bone, muscle, and other tissues.

4. Hypersecretion of GH during the growth years
(before ossification of the epiphyseal plates)
causes an abnormally rapid rate of skeletal growth.
This condition is known as gigantism (see figure,
left). Hypersecretion after skeletal fusion has
occurred can result in acromegaly, a condition in
which cartilage still left in the skeleton continues
to form new bone.
HYPERSECRETION

5. Hyposecretion of GH during growth years may
result in studend body growth, known as pituitary
dwarfism. For merly, patients were treated only
with GH extracted from human tissues.

6. GH affects metabolism in these ways:
• Promotes protein anabolism (growth, tissue repair)
• Promotes lipid mobilization and catabolism
• Indirectly inhibits glucose metabolism
•Indirectly increases blood glucose Levels

7. Prolactin (PRL), produced by acidophils in the pars
anterior, is also called lactogenic hormone. Both names of
this hormone suggest its function in “generating” or
initiating milk secretion (lactation). During pregnancy, a
high level of PRL promotes the development of the breasts
in anticipation of milk secretion birth of an infant, PRL in
the mother simulates the glands to begin milk secretion.
Hypersecretion of PRL may cause lactation in normal
women, disruption of the menstrual cycle, and impotely
men. Hyposecretion of PRL is usually insignificant exe
women who want to nurse their children. Milk production
not be initiated or maintained without PRL.
PROLACTIN

8. Tropic hormones are hormones that have a
simulating other endocrin gland. These hormones
stimulate the ment of their target glands and
tend to stimulate synthesis creation of the target
hormone . Four principal hormones are produced
and secreted by the basophils of the anterior.
1. Thyroid-stimulating hormone (TSH) or
thyrotrophic motes and maintains the growth
and development target gland-the thyroid.
TSH also causes the gland to secrete its
hormones.
TROPIC HORMONE

9. A hormone (ACTH), or adrmcotropin, promotes and
maintains normal growth development of the cortex of
the adrenal gland. ACTH also stimulates the adrenal
cortex to synthesize and secrete some of its hormones.
ADRENOCORTICOTROPIC HORMONE

10. HYPERSECRETION OF TROPIC HORMONE
secretion of the tropic hormones may result form a
pituitary induce the tropic hormones produced at higher
than level cause hypersecretion in their target gland. This
may result in effects throughout the body.
HYPOSECRETION OF TROPIC HORMONE
Hyposecretion of tropic hormones often causes their
target glands to secrete less than a normal amount of
their hormones may disrupt reproduction , kidney function ,
overall metabolism and other processes.

11. Control of secretion in the adenohypophysis
Cell bodies of neurons in certain parts of the
hypothalamus
Chemical that their axons secrete into the blood.
chemicals, generally called releasing hormones,
travel through a complex of small blood vesels
called the hypophyseal system.
CONTROL OF SECRETION IN
ADENOHYPOPHYSIS

12. Growth hormone – releasing hormone (GHRH)
Growth hormone – inhibiting hormone (GHIH)
(also called somatostatin (SS)
Corticotropin-relasing hormone (CRH)
Thyrotropin-relasing hormone (TRH)
Gonadotropin-releasing hormone (GnRH)
Prolactin-relesing hormone (PRH)
Prolactin-inhibiting hormone (PIH)
The following is a list of some of the
important hormones secreted by the
hypothalamus in to hypophyseal portal
system .

13. Clinical facts furnish interesting evidence about
feedback control of hormone secretion by the
anterior pituitary gland and its target glands.
For instance, patients who have the pituitary
gland removed (Hypophysectomy) surgically or
by radiation must be given hormone
replacement therapy for the rest of their lives. If
not they will develop thyroid, adrenal cortical,
and gonadotropic deficiencies-deficiencies of
the anterior pituitary’s target gland hormones.
CLINIC AL EVIDENCE OF FEEDBACK
CONTROL

14. Therefore both psychosomatic (mind
influencing the body) and somatopsychic (body
influencing the mind) relationship exist
between human body systems and the brain
Hypothalamus
FSH & LH GH
Anterior Pituitary
GHIH/SSGHRHGnRH TRH PRIH PRH CRH
TSH Prolactin ACTH
+ - -+ + + - + +

15. Thank you