1. ThemeTheme:: Hormones asHormones as
biological regulators.biological regulators.
General mechanismsGeneral mechanisms
of hormones action.of hormones action.

2. Highest level –
nervous system
Intermediate -
hormonal
regulation
Intracellular
(enzymes)
Levels of the homeostasis
regulation

3. Hormones – organic biologically active compounds
of different chemical nature that are produced
by the endocrine glands, enter directly into blood
and accomplish humoral regulation of the
metabolism of compounds and functions on the
organism level.
Hormonoids (tissue hormones) – compounds that
are produced not in glands but in different
tissues and regulate metabolic processes on the
local level, but some of them (serotonin,
acetylcholine) enters blood and regulate
processes on the organism level.

4. 1. Hypothalamus
2. Pituitary
3. Epiphysis
4. Thymus
5. Thyroid gland
6. Parathyroid glands
7. Langergans’ islands
of pancreas
8. Epinephrine glands
9. Sex glands
Endocrine glands:

5. Functions of hormones.
Hormones regulate the following processes:
1. Metabolic pathways Metabolic regulation
requires rapidly acting mechanisms. Many of the
hormones involved therefore regulate
interconversion of enzymes (glycogen, fat).
2. Digestive processes Digestive processes are
usually regulated by locally acting peptides
(paracrine).
3. Maintenance of ion concentrations
(homeostasis). Concentrations of Na+, K+, and
Cl– in body fluids, and the physiological
variables dependent on these (e. g. blood
pressure), are subject to strict regulation.

6. Classification of hormones
 hormones of protein structure: all hormones of
anterior pituitary (except ACTH), insulin,
parathyroid hormone;
 hormones of peptide structure: ACTH,
calcitonin, glucagon,hormones of posterior
pituitary, factors of hypothalamus, thymozin;
 steroid hormones: adrenal cortical steroids, sex
hormones;
 hormones - derivatives of amino acid: thyroid
hormones, adrenal medulla hormones, epiphysis
hormones;
 hormones derivatives of unsaturated fatty acid:
prostaglandins.

7. Transport of hormones in blood
Protein and peptide nature – in free state
Steroid hormones and hormones of thyroid
gland – bound with alpha-globulins or
albumins
Catecholamines – in free state or bound with
albumins, sulphates or glucuronic acid
Reach the target organs
Cells have the specific receptors to certain
hormone

8. Receptors of hormones
Two groups:
-placed on the surface of membrane – peptide
and protein hormones, prostaglandins;
-placed inside the cells (cytoplasm, nucleus) –
steroid and thyroid hormones
Prostaglandins, peptides Vitamin D, steroids Thyroid hormones
Second messenger
Activated protein kinase
Phosphorilated proteins
Biological action
Protein synthesis
NUCLEUS
m-RNA

10. Mechanism of water soluble hormones
action (not permeating into the cells):
Hormone (epinephrine, glucagon, ACTH, LH,
FSH, TSH, parathyroid hormone, calcitonin)
arriving at the surface of the cell becomes bound
to the specific receptor sites on the outer surface
of the cell membranes. Its binding is believed to
cause a local conformational change in the
membrane resulting in the activation of
adenylate cyclase, located on the inner surface
of the cell membrane. The active form of
adenylate cyclase converts ATP into cyclic
AMP. The cyclic AMP so formed then binds to
the regulatory subunit of protein kinase,
releasing its catalytic subunit in an active form.

15. Mechanism of steroid hormones action
(permeating into the cells):
• In difference to hormones of protein and
peptide nature, receptors for steroid hormones
are located within the cells - in the cytoplasm.
From cytoplasm the hormone-receptor
complexes is translocated into the nucleus
where they interact with DNA of nuclear
chromatin causing the activation of genes for
respective enzyme proteins.
• So, if hormones of the first group cause the
activation of existing enzyme molecules, the
acting on the target cells of steroids and
thyroid hormones results in the biosynthesis
of new enzyme molecules.

18. Hypothalamus
3 peptides are
synthesized and
migrate along axons
into posterior lobe of
pituitary
1) Antidiuretic hormone
(vasopressin)
2) Oxytocin
3) Neurophysin (promotes
transport of vasopressin
and oxytocin into pituitary
gland)
Two groups of hormones
are produced by
hypothalamus
corresponding to the
anterior and posterior
pituitary.

19. Hypothalamus and anterior pituitary
Bound with
anterior pituitary
by the capillary net
– hypothalamic
portal system
Releasing factors
and statins rich
the anterior
pituitary via this
system

20. •somatoliberin,
•thyroliberin,
•corticoliberin,
•foliliberin,
•prolactoliberin,
•luteinising-hormone liberin,
•melanoliberin
•somatostatin,
•prolactostatin,
•melanostatin
Secretion of liberins and statins by hypothalamus is
carried out under the effect of nervous impulses
and as result of the change of concentrations of
certain hormones in blood (feedback regulation).
Releasing factors (liberins) stimulate secretion of
pituitary hormones; statins - inhibit.

21. TROPIC HORMONES OF PITUITARY
Somatotropic hormone (growth hormone)
Chemical nature – simple protein
It is secreted continuously during the whole life
Secretion is stimulated by somatoliberin, is
inhibited by somatostatin
Main function – stimulates somatic
growth of organs and tissues,
particularly bones, cartilages, muscles.

22. Acts both directly and through the stimulation
of the formation of polypeptides somatomedins
(insulin-like growth factors).
ILGF are synthesized in liver

23. 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.

24. In the inherited
hypoplasia of pituatary
gland dwarfism is
developed.
For the treatment GH is
used.

25. 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

26. 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

27. 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

28. 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

29. 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

30. Gonadotropic hormones
Chemical nature – protein (glycoprotein)
Secretion is stimulated by foliliberin
Function: stimulates the function of follicles in
women and spermatogenesis in men
Follicle-stimulating гормон
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

31. 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

32. Lipotropic hormones
Chemical nature – simple
proteins
Functions:
-mobilization of lipids from
depot;
-melanocyte stimulating
function;
-decrease Ca in blood

33. THE INTERMEDIATE LOBE OF
PITUITARY
Chemical nature – peptide
Functions:
-stimulates melaninogenesis;
-adaptation of vision in darkness
Melanocyte stimulating hormone (melanotropin)

34. POSTERIOR LOBE OF PITUITARY
Chemical nature – peptide
Vasopressin (antidiuretic hormone)

35. 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)

36. Oxytocin
Chemical nature – peptide

37. 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

38. EPIPHYSIS (PINEAL GLAND)
Produces:
• Мelatonin from serotonin (regulates the
pigment metabolism)
 Adrenoglomerulotro-
pin – stimulates
secretion of
mineralocorticoids in
the epinephrine glands
cortex.
 Inhibitor of
gonadotropin – inhibits
the synthesis of
prolactin, cholesterol

39. PANCREAS
Exocrine and endocrine parts
Endocrine – Langerhans islets (alpha-,
beta- and delta-cells)

40. Alpha-cells: glucagon
Beta-cells: insulin
Delta-cells: somatostatin
Epithelium of ducts: lipocain

41. Insulin
 Nature – protein (51 АA)
 Is formed from proinsulin by proteolisis
 Contains zinc

42. • Regulation of the synthesis:
- Glucose concentration in blood
- Other hormones (somatostatin)
- Sympathetic and parasympathetic nervous
system
It is destroyed by insulinase (enzyme of liver)
Target cells:
• Hepatocytes
• Myocytes
• Adipocytes
In the unsufficiency – diabetes mellitus

43. The effect on carbohydrate
metabolism
•Increases the permeability of
membranes for glucose
•Activates glucokinase (hexokinase) in
glycolysis
•Activates TAC (citrate synthase)
•Activates PPP (G-6-PDH)
•Activates glycogen synthase
•Activates pyruvate- and alpha-
кetoglutarate dehydrogenase
•Inhibits gluconeogenesis
•Inhibits the decomposition of glycogen
(glucose-6-phosphatase)

44. Effect on the protein metabolism
•Increases the permeability of membranes
for AA
•Activates synthesis of proteins and nucleic
acids
•Inhibits gluconeogenesis
Effect on the lipid metabolism
•Activates of the lipids synthesis
•Promotes the saving of fats activating the
decomposition of carbohydrates
•Inhibits gluconeogenesis
Effect on the mineral metabolism
•Activates Na/K-АТP-аse

45. Glucagon
 Nature – polypeptide
 Antagonist of insulin
 Synthesis is activated in fasting

46. Functions
 Activates the
decomposition of
glycogen in liver
 Activates
gluconeogenesis
 Inhibits glycolysis
 Activates lipolysis

47. The eicosanoids are a group of signaling
substances that arise from the C-20 fatty acid
arachidonic acid and therefore usually contain
20 C atoms (Greek eicosa = 20). As mediators,
they influence a large number of physiological
processes. Eicosanoid metabolism
is therefore an important drug target. As
short-lived substances, eicosanoids only act
in the vicinity of their site of synthesis (paracrine
effect).