Transcript Hormones of a pituitary gland

TROPIC HORMONES OF PITUITARY
Somatotropic hormone (growth hormone)
Chemical nature – simple protein
It is secreted continuously during the whole life
Secretion is stimulated
inhibited by somatostatin
by
somatoliberin,
is
Main function – stimulates somatic growth
of organs and tissues, particularly bones,
cartilages, muscles.
Acts both directly and through the stimulation of the
formation of polypeptides somatomedins (insulin-like
growth factors).
ILGF are synthesized in liver
The effect of STH on the
protein metabolism
• Promotes the entrance of AA into cells,
• Inhibits catabolism of proteins and AA
• Activates the synthesis of proteins, DNA,
RNA.
The effect of STH on the carbohydrate
metabolism
 Antiinsulin hormone – activates insulinase of liver
 Activates the exit of glucose from liver
 Inhibits the conversion of glucose into fat
The effect of STH on lipid
metabolism


Stimulates the decomposition of lipids (lipolisis)
Stimulates the oxidation of fatty acids.
In the inherited
hypoplasia of pituatary
gland dwarfism is
developed.
For the treatment GH is
used.
Hyperproduction of GH
before puberty and
before the completion of
ossification results in
gigantism
Yao Defen, the
tallest women
in the life,
2.36 м
Hyperfunction of pituitary inadults
results in acromegaly –
unproportionally intensive growth
of particular body parts (fingers,
nose, lower jaw, tongue, inner
organs).
Cause –
tumor of
anterior
pituitary
Adrenocorticotropic hormone (АCTH)
Chemical nature – polipeptide
Secretion is stimulated by corticoliberin
Feedback regulation of the speed of secretion
depending on the cortisol level
Controls the cortex of epinephrine gland where
cortisol is produced:
-promotes the increase of cholesterol content in
epinephrine glands cortex and its conversion into
corticosteroids;
-activates the passing of glucose into epinephrine
glands and pentose phosphate cycle (NADPH
synthesis)
-has melanocyte stimulating activity
Cushing’s disease
Cushing's disease – hyperproduction of
ACTH (adenoma in a pituitary gland) which
in turn elevates cortisol.
Obesity, particularly of the trunk and face
(“moon face“) with sparing of the limbs;
striae (stretches of the skin)
Proximal muscle weakness
Hirsutism (facial male-pattern hair growth)
Insomnia,
impotence,
amenorrhoea,
infertility
Heart diseases, hypertension
Polyuria,
hypokalemia
hyperglycemia,
glucosuria (steroid diabetes)
Kidney bones
Depression, anxiety
Hyperpigmentation
Thyrotropic hormone (ТТH)
Chemical structure – protein (glycoprotein)
Secretion is stimulated by thyroliberin
The speed of secretion is regulated according to
the feedback regulation by thyroid hormones
It is necessary for the normal functioning of
thyroid gland:
-promotes the accumulation of iodine in thyroid
gland and its insertion into tyrosine;
-stimulates the synthesis of try- and
tetraiodthyronin
Gonadotropic hormones
Follicle-stimulating гормон
Chemical nature – protein (glycoprotein)
Secretion is stimulated by foliliberin
Function: stimulates the function of follicles in
women and spermatogenesis in men
Luteinizing hormone
Chemical nature – protein (glycoprotein)
Secretion is stimulated by luliberin
Function: stimulates the follicular growth and
conversion of the follicle into a corpus luteum n
women and secretion of testosterone in men
Prolactin
Chemical nature – protein
Secretion is stimulated by prolactoliberin
Functions:
-stimulates the function of mammary glands
(lactation);
-provides the body with sexual gratification
after sexual acts
-stimulates the function of corpus luteum
(progesterone secretion);
-stimulates the growth of tissue of prostatic
gland in men;
-responsible for the mother instinct
Lipotropic hormones
Chemical nature – simple proteins
Functions:
-mobilization of lipids from depot;
-melanocyte stimulating function;
-decrease Ca in blood
THE INTERMEDIATE LOBE OF
PITUITARY
Melanocyte stimulating hormone (melanotropin)
Chemical nature – peptide
Functions:
-stimulates melaninogenesis;
-adaptation of vision in darkness
POSTERIOR LOBE OF PITUITARY
Vasopressin (antidiuretic hormone)
Chemical nature – peptide
Functions:
-activates hyaluronidase which decomposes
hyaluronic acid in the membranes of kidney
canaliculi – increases the reabsorption of water
in kidneys;
-contractions arterioles and capillaries –
increases blood pressure
Insufficiency – diabetes insipidus (polyuria, low
density of urine, dehydratation)
Oxytocin
Chemical nature – peptide
Functions:
-stimulates the contraction
of smooth muscles (of
uterus during labor)
-stimulates milk secretion
(contraction
of
muscle
fibers around mammary
alveoli)
Using:
-for labor stimulation;
-to
stop
after
labor
hemorrhage;
-for stimulation of milk
secretion