HORMONES

THYROID GLAND

Hormones of two types: 1. Iodine containing :

thyroxin (tetraiodthyronin) and triiodthyronin – derivatives of tyrosine;

2. Calcitonin - peptide

Synthesis of iodine containing hormones is regulated by thyrotropic hormone, which in turn is stimulated by thyroliberin

Functions of iodine containing hormones

Necessary for normal growth, differentiation, sex and mental development

Regulate the speed of metabolism

Effect on protein metabolismIn physiological concentration stimulate synthesis of proteins, nucleic acids. In the increased concentration activate the protein decomposition.

Effect on carbohydrate metabolismAccelerate the absorption of carbohydrates in the intestineActivate the decomposition of glycogen.

Effect on lipid metabolismActivate the exit of lipids from depot, its decomposition and oxidation

Effect on energetic metabolismIn excess thyroxin uncouples respiration and phosphorilation, decreases the ATP formation and increases the heat formation

Hyperfunction of gland – diffuse toxic goiter

(thyrotoxicosis, Graves disease)

•Goiter – hyperplasia of gland•Hypermetabolism•Increase of body temperature•Sweating, muscle weakness•Weight loss with good appetite •Tremor, emotional lability, insomnia •Exophtalm

Hypofunction of gland (occurs in the deficit of iodine in water,

soil, air)

•Decrease of metabolism•Decrease of body temperature

Hypofunction in childhood - cretinism•Growth inhibition•Unproportional body development•Disorders of mental development

Hypofunction in adults – mixedema•Edema of mucosa

mixedema

cretinism

Endemic goiter (occurs in the deficit of

iodine in water, soil and air)

Connective tissue is enlarged in gland and it is increased in size markedly

Calcitonin Is synthesized by

parafollicular cells of thyroid gland

Affects the metabolism of Са and Р - Promotes the transferring of Са2+ from blood into

bones- Inhibits reabsorption of Р in kidneys (decreases the

content of Р in blood due to its excretion with urine)

Increase of calcitonin- hypocalciemia- hypophosphatemia- hyperphosphaturia

Decrease of calcitonin

- hypercalciemia- hyperphosphatemia- hypophosphaturia

PARATHYROID GLANDS Parathyroid hormone - protein

Affects the metabolism of Са and Р

- Promotes moving of Са2+ from bones into blood

- Inhibits reabsorption of Р in kidneys (decreases the content of Р in blood due to its excretion with urine)

- Stimulates the absorption of Ca in the intestine

Promote vit D transformation in kidney ( formation of active vitD3)

Hyperfunction (Recklinghausen’s disease)

- hypercalciemia- hypophosphatemia- hyperphosphaturia- osteoporosis- Accumulation of Са in

tissues

Hypofunction- hypocalciemia- hyperphosphatemia- hypophosphaturia- tetanus

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

» 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

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

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

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

Functions Activates the

decomposition of glycogen in liver

Activates gluconeogenesis

Inhibits glycolysis Activates lipolysis

EPINEPHRINE GLANDS Two parts:

-cortex

-medulla

Hormones of medulla - catecholamines

Epinephrine, norepinephrine and DOPA Nature – derivatives of tyrosine Excretion is regulated by sympathetic nervous system

and brain cortex

Epinephrine

Norepinephrine

Functions:Stress hormones. Contraction of vessels, increase the blood

pressure, accelerate pulse. Contraction of uterus muscles. Epinephrine relaxes the muscles of bronchi and intestine.

On carbohydrate metabolism:

-activates the decomposition of glycogen in liver and muscles

-activates glycolysis, PPC, TAC and tissue respiration

On protein metabolism

-accelerate the decomposition of proteins

On lipid metabolism

-activates lipase, mobilization of lipids and their oxidation

Hormones of cortex - corticosteroids

There are more than 50 corticosteroids Nature – steroids Are synthesized from cholesterol

Two groups

-glucocorticoids (protein, carbohydrate and lipid metabolism)

-mineralocorticoids (mineral metabolism)

Glucocorticoids

Most important: corticosteron, cortison, hydrocortison

Synthesis is regulated by ACTH

Are transported combined with proteins

Half-life time – till 1 hour

In the decomposition17-ketosteroids are formed (excretion with urine). Diagnostic significance – index of the function of cortex of epinephrine glands and testis

Functions

• Antiinflammatory, antiallergic, antiimmune• Adaptive effect• Maintain the blood pressure• Maintain the volume of extracellular liquid

Effect on protein metabolism

• Stimulate catabolic processes in connective, lymphoid and muscle tissues

• Activate protein synthesis in liver• Stimulate amino transferases• Stimulate the urine biosynthesis

Effect on the carbohydrate metabolism

Increase the glucose level• Activate gluconeogenesis• Inhibit hexokinase (glycolisis)

Effect on the lipid metabolism• Activate lipolysis• Activate the conversion of FA into carbs

MineralocorticoidsThe most important hormone: aldosteron

Excretion is controlled by rhenin-angiothensin system

Functions:

-activate the reabsorption of Na, water and Cl in kidney canaliculi

- Promotes the excretion of К ions via the kidneys, skin and saliva

Disorders of the function of epinephrine gland cortex

Insufficiency: Addison disease (bronze disease)

Causes:

-injury of epinephrine gland cortex

-insufficient production of ACTH

Blood pressure decrease, loss of weight, weakness, anorexia.Hyperpigmentation - bronze skin

Hyperproduction: Kushing syndrom

Causes: hypeplasia or tumor of epinephrine gland cortex

Obesity, particularly of the trunk and face (“moon face“) with sparing of the limbs; striae (stretches of the skin)Proximal muscle weaknessHirsutism (facial male-pattern hair growth)Insomnia, impotence, amenorrhoea, infertilityHeart diseases, hypertensionPolyuria, hypokalemia hyperglycemia, glucosuria (steroid diabetes) Kidney bonesDepression, anxietyHyperpigmentation

Aldosterone hyperproduction

Causes:

-aldosteroma

Symptoms:

-hypokaliemia

-hypernatriemia

-hyperchloremia

-hypervolemia

-edema, hypertension

A little amount of female sex hormones is formed in male organism and vice versa.

Female – estrogens, progesteron.

Male – androgens.

Sex hormones

Are synthesized in:

-sex glands

-placenta

-cortex of epinephrine glands

EstrogensNature: steroids

Estradiol – is formed in follicles of ovarium

Estron and estriol – are formed in liver and placenta in the metabolism of estradiol

Estradiol estriol

Functions of estrogens

Development of the female reproductive system organs

Ability to fertility in reproductive period

Biochemical functions of estrogens

Anabolic action on the tissues of reproductive organs

Inhibit the exit of Ca from bones (osteoporosis in menopause)

ProgesteronNature: steroid

Is formed in corpus luteum, placenta and epinephrine glands

Functions of progesteronPrepares the endometrium of uterus to

implantation of ovum

Inhibits the uterus contraction during pregnancy

Stimulates the growth of mammary glands

AndrogensTestosteron

Nature: steroid

Is formed in the interstitial cells of testis

Is excreted as 17-кetosteroids

Functions of testosteroneDevelopment of the primary sex features

Development of the secondary sex features

Stimulates spermatogenesis

Biochemical functions of testosteroneStrong anabolic action (stimulates the synthesis of

NA, proteins, phospholipids) – increases the mass of muscles

Keeps the Ca and P in organism

Derivatives of androgens – active anabolics