endocrine Flashcards
what are hormones?
they are chemical messengers produced by endocrine glands and they regulate metabolic function of the cells in our body
elicits a specific response in distant target tissues
how are hormones transported to target cells?
by the circulation or blood at a very low concentration
how does hormone work on target cells?
the hormone enters the blood stream and is distributed throughout the entire body and there are receptors on tissues for example on skeletal muscle tissue then when the hormones get there binding occurs and hormonal effects appear
what are the 4 major chemical classes of hormones?
amines
peptides
glycoproteins
steroids
what are amine hormones?
they include:
catecholamines (dopamine, epi and norepi)
thyroid hormones(T3 & T4) and melatonin
amine hormones are derived from?
amino acid called tyrosine and tryptophan
amine hormones are secreted by?
adrenal medulla, thyroid and pineal glands( melatonin)
____are the largest group of hormones?
peptide hormones
where are peptide hormones synthesized in?
in the rough endoplasmic reticulum of endocrine cells as an inactive preprohormones
list peptide hormones
hypothalamus: all releasing hormones
pituitary gland: ACTH, GH, MSH, ADH, prolactin and oxytocin
pancreas: insulin and glucagon
parathyroid gland: parathyroid hormone
C cells of the thyroid gland: calcitonin
what are glycoprotein hormones?
they contain long polypeptide bound to one or more carbohydrate groups
list glycoprotein hormones
TSH
FSH
LH
where does steroid hormones come from?
they are synthesized from cholesterol
list steroid hormones
cortisol
aldosterone
testosterone
estrogen
progesterone
features of steroid hormones?
they are not stored in vesicles and rapidly diffuse out of the cell once they are synthesized due to their high lipid solubility
they require carrier proteins in the blood due to their low water solubility
what are other organs that produce hormones?
placenta: HCG or human chorionic gonadotropin
heart: ANP or atrial natriuretic peptide
stomach: gastrin
small intestine: CCK, secretin
kidney: renin, 1-25-dihydroxycholecalciferol and erythropoietin
fat cells/ adipose tissue: leptin or adipokines
GIT: ghrelin
what does hCG do?
it maintains corpus luteum early in pregnancy
what does atrial natriuretic peptide do?
it reduces blood pressure, blood volume and blood sodium concentration
it also increases renal Na+ excretion
what does gastrin do?
it stimulates HCl secretion by parietal cells of gastric mucosa
what does CCK do?
it stimulates release of pancreatic enzymes
contracts gallbladder
relaxes sphincter of oddi
inhibits stomach motility or delay gastric emptying
what does secretin do?
increases fluid and HCO3 secretion by pancreatic duct
feedback inhibition of gastric H+ secretion
what does renin do?
it cleaves circulating angiotensinogen to angiotensin I
what does 1-25-Dihydroxycholecalciferol do?
it stimulates gastrointestinal Ca2+ and phosphate absorption
what does erythropoietin do?
it stimulates RBC production
what does leptin do?
it activates satiety center of hypothalamus which suppresses appetite
what does ghrelin do?
it activates hunger center of the hypothalamus which stimulates appetite
where is the receptors for steroids hormone located?
in cytoplasm
where is the receptor for thyroid hormones located?
on the nucleus
where is the receptor for protein, peptide and catecholamines hormones located?
on the surface of cell membrane
true or false: hormones can act directly on target cells
false, hormones never act directly they need to combine with specific receptors
what are receptors?
they are large protein molecules and they are present either on the surface of cells or inside a cell like the cytoplasm or in nucleus
cells give a response to a particular hormone if only there’s—?
if only there’s specific receptors for that hormone
what are first messengers?
are extracellular factors, often hormones or neurotransmitters, such as epinephrine, growth hormone, and serotonin
the binding of a hormone to it’s receptor causes the generation of intracellular signaling molecules called___
second messengers
what are second messengers
are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules—the first messengers.
what does second messengers do?
they amplify the hormonal signal within the target cells
-> they trigger physiological changes at cellular level such as proliferation, differentiation, migration, survival, apoptosis and depolarization.
second messengers use___ to bring changes in cellular activity
the stimulation of kinases
what are kinases?
they are enzymes that phosphorylate target proteins
list common second messengers
cAMP
DAG and IP3
cGMP
Ca2+
explain how cAMP is a second messenger
- the hormone receptor complex associates with intracellular heterotrimeric G proteins
- this combination activates adenylyl cyclase protein enzyme which is also located in the membrane also but a large portion of it protrudes in the cytoplasm
- the activated adenylyl cyclase convert ATP into cAMP
- cyclic AMP activates cytoplasmic protein kinases
- activated protein kinases which affects cellular activity through phosphorylation of the effector proteins
the cAMP signal is terminated when cAMP is broken down by the action of a phosphodiesterase enzyme
what does hypothalamus do?
->it receives signals from almost all sources in NS
->it acts as a collecting center for internal body
informations
->it control secretion of pituitary gland hormones
what controls the pituitary gland?
by releasing hormones of the hypothalamus
and by target hormones which is negative FB system
why is the pituitary called the master gland
because it control different peripheral target glands
what is the hypothalamic pituitary axis?
is an intricate pathway with a central role in maintaining homeostasis by integrating complex physiological and endocrine inputs, and neuronal and hormonal output
___is a well studied interface between the nervous system and endocrine system
hypothalamic pituitary axis
what are the organs that are directly or indirectly affected by the axis?
reproduction
growth
lactation
stress response
metabolism
water balance
immune system
what are the 2 connections of the hypophyseal pituitary axis?
vascular connection and neural connection
which has organ has vascular connection?
the anterior pituitary lobe
which organ has a neural connection?
the posterior pituitary lobe
the vascular connection is between?
the hypothalamic and the hypophyseal portal circulation
what does the vascular connection in anterior pituitary lobe do?
hormonal regulation by releasing hormones of the hypothalamus and by feedback from the target gland hormones
the neural connection is between?
the hypothalamic and the hypophyseal tract
the neural connection is regulated by?
the neuroendocrine reflex
the hormones secreted by the anterior pituitary are called?
trophic hormones
high anterior pituitary hormones cause their target organs to be___
hypertrophy
low concentration of anterior pituitary hormones cause their target organs to be___
atrophy
GH is released from?
somatotroph cells of the anterior pituitary glands
what does GH control of release?
GHRH+ and GHIH- of the hypothalamus
what is the target organ of GH?
most tissues
what are the actions of GH?
-> it stimulates protein synthesis and cell growth via somatomedins or IGF-1 released from liver
-> lipolysis and increased blood glucose
-> it causes growth of all tissues
-> it promotes hypertrophy and hyperplasia
how does GH promotes overall tissues and organ growth?
by promoting the movement of amino acids into cells and the incorporation of these amino acids into proteins
linear growth occurs indirectly through the stimulation of?
insulin like growth factor or IGF-1 secretion
___is the most important endocrine regulator of final body size
GH
how does GH exerts effect on bones?
it causes liver to form somatomedins or IGF that strongly increases all aspects of bone growth
how does somatomedins increase bone growth?
->by stimulating osteoblasts
->increased protein deposition by chondrocytic and osteogenic cells
what are the metabolic effects of GH?
effects on protein metabolism
effects on fats
effects on CHO
list the effects on GH in protein metabolism
increases transport of a.a through cell membrane
increase protein synthesis by ribosome
decreases protein catabolism
it stimulates nucleus for formation of RNA
so GH increases protein synthesis
how does GH have effect on fats?
it has a lipolytic effect or gives energy
effects of GH on CHO?
it has diabetogenic effect, which means its anti insulin action and it increases blood glucose
list the effect of GH on CHO
decrease glucose utilization in muscle
decrease number of insulin receptor
decrease glucose uptake by the cells
enhance gluconeogenesis in the liver
what are defects in GH secretion in childhood?
gigantism and dwarfism
what are defects in GH secretion in adulthood?
acromegaly
what is gigantism?
it is caused by GH excess
what does gigantism result in?
it increase linear height because the epiphyseal growth plates in the long bones are open
what’s the cause for gigantism?
a GH secreting pituitary tumor
what is dwarfism?
it is GH deficiency
what does dwarfism result in?
short stature and growth retardation
what is acromegaly
it’s GH excess in adults
what causes acromegaly?
excess secretion of GH after puberty
what are the characteristics of acromegaly
linear height is fixed due to closure of the growth plates in long bones
the hands, feet, jaw, forehead and nose continue to grow giving patients a characteristic appearance
why is GH excess associated with hyperglycemia?
its likely to cause DM due to the anti insulin actions of GH
from where is the thyroid stimulating hormone released?
from thyrotroph cells of anterior pituitary
what is the control of release of TSH?
TRH of the hypothalamus and coldness+
T3 and T4- and negative FB
what is the target organ of TSH?
thyroid gland
what is the action of TSH?
->it stimulates the thyroid gland to produce and secrete thyroxine T4 or triiodothyronine T3
->it maintain the structural integrity of the thyroid gland
from where is the adrenocorticotropic released?
the corticotroph cells of the anterior pituitary gland
what is the control of release of ACTH?
CRH of the hypothalamus +
glucocorticoids - and negative FB
what is the target organ of ACTH?
adrenal cortex
what is the action of ACTH?
->it stimulates the adrenal cortex to secrete glucocorticoids like hydrocortisone or cortisol
->it promotes structural integrity of the adrenal cortex
where is follicle stimulating hormone released from?
from gonadotroph cells of the anterior pituitary glands
what is the control of release of the FSH?
GnRH of the hypothalamus+
prolactin, estradiol and inhibin-, negative FB+ prolactin
what is the target organ of the FSH?
gonads
what is the action of the FSH?
->it acts on testicular Sertoli cells in the male and follicular granulosa cells in the female
->stimulates the growth of ovarian follicles + production of estrogen in females
-> stimulates the production of sperm cells which is spermatogenesis via Sertoli cells of the testis of males
from where is luteinizing hormone released from?
released from gonadotroph cells of the anterior pituitary glands
what is the control of release of LH?
GnRH of the hypothalamus+
prolactin, testosterones and negative FB
before ovulation+ and after ovulation- it releases estradiol
what is the target organ of LH?
gonads
what is the action of LH?
-> it stimulates ovulation and the conversation of the ovulated ovarian follicle into an endocrine structure called a corpus luteum in females
-> stimulates the secretion of male sex hormones mainly testosterones from the interstitial cells or Leydig cells in the testes
from where is the prolactin released?
from lactotroph cells of the anterior pituitary glands
what is the control of release of PRL?
-> inhibited by PIH, prolactin inhibiting hormone dopamine
->secretion increases during pregnancy and peaking near the time of parturition
-> sucking and tactile stimulation of the nipples increase the secretion
->negative FB mechanism facilitates the secretion of dopamine and regulate it’s own secretion
___inhibits the effects of gonadotropins and prevent ovulation in lactating women
PRL
what is the action of PRL?
-> stimulation of milk production by the mammary glands of women after the birth of a baby and mammary gland development
-> negative FB regulation of gonadotropins which are FSH and LH
->acts on the kidneys to help regulate water and electrolyte balance
clinical correlates to PRL?
hyperprolactinemia and hypoprolactinemia
hyperprolactinemia can occur form?
overproduction or loss of the dopamine inhibitory effect
the overproduction of PRL can be from?
a prolactin secreting pituitary adenoma
in hyperprolactinemia the loss the dopamine inhibitory effect can be from?
use of antipsychotic drugs or damage to the pituitary stalk
what is the key clinical indicator of hyperprolactinemia?
galactorrhea or milky nipple discharge
hypoprolactinemia can occur due to?
with other adenohypophysial deficiencies
the clinical effect of hypoprolactinemia is?
inhibition of lactation
what is the other name of GH?
somatotropin
what is the other name for TSH?
thyrotropin
what is the other name for ACTH?
corticotropin
what is the other name for FSH?
folliculotropin
what is the other name for LH?
luteotropin
which hormones are released from the gonadotroph cells of anterior pituitary?
FSH and LH
say something about hormones of neurohypophysis
Antidiuretic hormone and oxytocin are mainly synthesized in neuros cell bodies that originate in the supraoptic nucleus and paraventricular nucleus of the hypothalamus and then they are stored in the posterior pituitary
what is the control of release of ADH
neuroendocrine reflex
->ADH+ released in low levels of water like dehydration and decrease blood volume and pressure and it increase osmolar pressure detected by hypothalamus
->ADH- released to increase blood volume and BP to normal level
what is the target organ of ADH?
kidney tubules and blood vessels
what is the other name of ADH?
vasopressin
what is the action of ADH?
-> it has constricting effect on afferent arterioles so when it decreased GFR the urine output will also decreases
-> it increases the reabsorption of water at the collecting duct and collecting tubules
->it promotes aldosterone production from adrenal cortex
how does ADH promotes aldosterone production from adrenal cortex?
by Na+ retention and K+ excretion
how does ADH respond to decrease blood volume and pressure?
by increasing fluid retention at the kidney
and by increasing blood pressure through vasoconstriction
what happens when someone has ADH deficiency?
it results in the formation of dilute urine in which urine osmolarity will be less than that of plasma
the condition in which urine osmolarity will be less than that of plasma is called?
central diabetes insipidus
ADH deficiency will cause
dilute urine output
what is the control of release of oxytocin?
it also has neuroendocrine reflex
->during late pregnancy or trimester period and tactile stimulation of the mammary gland and sex organs
in nursing mothers the mechanical stimulus of sucking acts it will stimulate the reflex secretion of oxytocin via sensory nerve impulses to the hypothalamus
what is the target organ of oxytocin?
uterus and mammary gland
what is the action of oxytocin?
->it stimulates uterine contraction, it acts on the target cells by increasing the intracellular Ca+ content which leads to muscle contraction
-> it stimulates milk ejection from the lactating breast
->it promotes maternal behavior toward the neonate
how is oxytocin used clinically?
used for induction of labor if they pregnancy is prolonged
or in the case of severe pregnancy induced hypertension or preeclampsia
explain the mechanism of action of oxytocin on uterine smooth muscle contraction
-> oxytocin increases late in pregnancy causing a powerful uterine contraction response during labor
->distention of the uterine cervix stimulates the release of oxytocin via the neuronal pathway
->the uterine contractions that result further cervical distension
-> a cycle of positive feedback develops during the later stages of labor in which progressive cervical distention stimulates more oxytocin release
-> this cycle terminates with the birth of the infant
what are the 2 cells of thyroid gland?
follicular and para follicular cells
what’s the function of follicular cells of thyroid gland?
it synthesizes and secretes the principal thyroid hormones T4 and T3
what is the ratio of T4 and T3?
4:1
which thyroid hormone is the most biologically active?
T3
what is the function of para follicular cells?
it synthesizes and secretes calcitonin
why does the thyroid hormones have wide spread effect?
because it has calorigenic action which is stimulating oxygen consumption
through the activation of genes thyroid hormones stimulate…?
-> protein synthesis
->promote maturation of the nervous system
-> increase the rate of cell respiration in most tissues
->they are need for proper growth and development
what are the metabolic functions of thyroid hormones?
->are primarily responsible for determining the BMR, it either increase the BMR and oxygen consumption of most of tissues of the body
-> they increase synthesis of many intracellular enzymes and increase activity of Na+ K+ and ATPase which increase the rate of transport of both Na+ and K+ through the cell membrane, this process utilized energy and increase heat production
what’s the action of thyroid hormones on mitochondria?
they increase the size, number and activity of mitochondria which will increase the rate of formation of ATP to enhance cellular function
what’s the action of thyroid hormones on ribosomes?
->they increase the rate of formations of proteins by the ribosomes via mRNA
->they increase mRNA synthesis by the genes which leads to a generalized increase in synthesis of many types of protein within the cells
-> large amount of thyroid hormone lead to excess catabolism of muscle protein
what’s the action of thyroid hormones on carbohydrate metabolism?
-> it increases the rate of absorption of carbohydrate from the GIT
-> they enhance glucogenesis and glycolysis
-> they increase enzymes acting on carbohydrates metabolism
what happens after carbohydrate meals and what’s thyroid association here?
blood glucose level increases but it normally falls again rapidly because of the rate of glucose utilization is also increased
the effects of thyroid on carbohydrate results from?
increases in the activity of enzymes
what’s the action of thyroid hormones on fat metabolism?
-> all aspects of fat metabolism are increased including synthesis, mobilization and utilization
-> it accelerates the oxidation of fatty acids by the cells
->it lowers the level of cholesterol, phospholipids and triglycerides in the blood
as thyroid hormone accelerates the oxidation of fatty acids by the cells so this means?
more lipolytic effect than lipogenic effect
what’s the action of thyroid hormones on skeletal growth and development?
->due to its protein synthesis by ribosomes its important for normal growth of soft tissues and skeleton
-> its required for production and action of GH and insulin like growth factors on skeleton growth and development
what’s the action of thyroid hormones on fetal and neonatal nervous system?
->it promote growth and development of the brain during fetal life and for the first few years of life
-> essential for normal myelination and development of the NS in infant
if there’s thyroid hormone deficiency what is its effect on infants?
-> growth and maturation of the brain s retarded
-> myelination is defective
-> the reflex time prolonged
if there’s thyroid hormone excess what is its effect on adults?
-> it causes an increased response of the brain to catecholamines and increases activation of reticular activating system
-> restlessness and hyper excitability
what’s the action of thyroid hormones on the cardiovascular system?
-> increase the number and affinity of beta-1 adrenergic receptors in the heart
-> it increases the heart sensitivity to catecholamine and catecholamine increases all properties of the heart
->increased metabolism in the tissues causes more rapid utilization of oxygen and causes greater metabolic end products to be released from the tissues
->these effects cause vasodilation thus increasing the rate of blood flow in the skin for heat elimination
->increase blood flow leads to increase venous return leading to increase in CO and systolic blood pressure
what’s the action of thyroid hormones on respiration?
->increase respiration due to increase rate of metabolism which increase the utilization of oxygen and formation of carbon dioxide
-> helps in dissociation of oxygen from hemoglobin by increasing the amount of 2,3 diphosphoglyceride in the RBC
what’s the action of thyroid hormones on GIT?
-> they increase the rate of secretion of the digestive juice and motility which leads to increased appetite and food intake
what’s the action of thyroid hormones on sexual functions?
-> normal amount is important for normal sexual function
-> essential for normal menstrual cycle and fertility
-> increase milk secretion in lactating women
thyroid malfunction is very common in which gender?
more prevalent in females
hyperthyroidism results from?
a secretory tumor of the thyroid gland or from an autoimmune condition as in graves diseases
what happens in graves diseases?
thyroid stimulating immunoglobulin are produced by the immune system
and these are agonists at the TSH receptor causing both hypersecretion and growth of the gland causing a goiter
what causes hypothyrodism?
inadequate production of thyroid hormones due to sufficient dietary iodine
inadequate amounts of T4 and T3 causes?
abnormally high levels of TSH secretion with lack of negative feedback inhibition which in turn stimulates the abnormal growth of the thyroid
hypothyroidism is usually a problem in?
a problem in thyroid gland and not with pituitary production of TSH
list the causes for goiter
-> iodine deficiency
-> anti thyroid drugs
-> thyroidal enzyme defects
all these cause decrease in T3, T4 synthesis and secretion and increase in TRH and plasma TSH
what is the other name for para follicular cells?
C cells
where are C cells found?
scattered outside of follicle epithelium
what is the function of calcitonin?
->lowers blood Ca+ levels
->inhibits osteoclasts cells of bones+
->stimulates osteoblast cells of bone
->increases urinary calcium loss
the secretion of calcitonin is triggered by?
high blood Ca+ level
what is parathyroid gland?
they are 4 glands embedded on posterior side of thyroid gland
___cells produce parathyroid hormone
chief cells
what is the control of secretion of PTH?
-> lowers blood Ca+ level
-> it act on bones osteoclast cells for bone resorption
->acts on GIT dietary absorption of Ca+
->act on kidneys to decrease Ca+ loss via renal excretion
what is PTH action?
it raises blood Ca+ to normal level
where is the adrenal glands located anatomically?
situated on superior border of each kidney surrounded by fibrous capsule
what are the 2 parts of adrenal gland?
the outer adrenal cortex and the inner adrenal medulla
the outer glandular region has__ layers
3 layers and the cells of the last 2 act as a single unit
what does the glandular region of outer adrenal cortex secretes?
->aldosterone
->cortisol
->sex hormones like androgen and estrogen
what does the neural tissues of an inner medulla secretes?
release catecholamines, 80% epi and 20% norepi
what are the 3 layer of adrenal cortex?
->zona glomerulosa, yehe outermost nw
-> zona fasiculata, middle
->zona reticularies, inner most
what does the zona reticularies of adrenal cortex secretes?
secretes glucocorticoids mainly cortisol and androgens
which adrenal gland doesn’t have nerve supply?
adrenal cortex
what does the zona glomerulosa produce?
the principal physiological mineralocorticoid hormone aldosterone
what the function of aldosterone?
->promotes the renal tubular reabsorption or retention of Na+
->secretion or excretion of K+ and H+
->it has major role in the maintenance of electrolyte and fluid balance and regulate mineral content in blood volume, water and electrolyte balance
the stimulation of aldosterone is triggered by?
decreased Na+
increased K+
decreased blood volume
BP and stress
the secretion of aldosterone is regulated by?
by renin, ADH and ACTH
what is the target organ of aldosterone?
renal tubules
aldosterone control of secretion is?
->high K+ of ECF detected by JGA and activated renin
-> low Na+ of ECF detected by hypothalamus and activate CRH and then ACTH which will release aldosterone and cortisol
-> dehydration which is detected by hypothalamus and activates ADH
what does the zona fasiculata produce?
glucocorticoids like cortisone and cortisol
glucocorticoids are released due to?
in response to ACTH
what’s the function of glucocorticoids?
->helps to resist long term stressors
->promote normal cell metabolism
prolonged ACTH secretion results in?
hypertrophy and hyperplasia of the adrenal cortex
what are actions of glucocorticoids?
-> are essential to give relief from prolonged stressors
-> increase gluconeogenesis
-> increase protein catabolism in muscle and decrease protein synthesis by providing more a.a to the liver for gluconeogenesis
->decrease glucose utilization and insulin sensitivity of adipose tissue
-> increase lipolysis which provide more glycerol to the liver gluconeogenesis
what are the anti inflammatory effects of glucocorticoids?
-> induce the synthesis of lipocortin which is an inhibitor phospholipase A
->inhibit the production of interleukin 2 and inhibit the proliferation of T- lymphocyte
->inhibit the release of histamine, serotonin from mast cells and platelets
it suppresses immune response
what is Cushing’s syndrome?
it’s excess of glucocorticoids
hypercortisolism is characterized by?
-> hyperglycemia due to enhanced gluconeogenesis
->muscle wasting and weakness due to protein catabolism
->truncal obesity and rounding of the face or moon face
->hypertension is common due to mineralocorticoid effects of excess glucocorticoids
what is Addison’s diseases?
caused by hyposecretion of corticosteroids especially glucocorticoids
what causes the pigment in Addison’s diseases?
results from stimulation of melanocytes by ACTH which is structurally similar to MSH
zona fasiculata is more or less similar to___
zona reticularies
what is the function of zona reticularies?
-> to form glucocorticoids cortisol and corticosterone
->and form lesser extent of androgens and estrogens
adrenal medulla is innervated by?
preganglionic nerve fibers of sympathetic NS and axons stimulate hormone secretion
what’s the function of adrenal medulla hormones?
-> increase heart rate and force releases glucose and fatty acids into blood and opens airways
they prepare the body to deal with short term stress
the release of catecholamines by adrenal medulla is controlled by?
preganglionic sympathetic neurons
Ach is released and acts at the nAchR of the chromaffin cells
what happens during the stress response?
it is sensed in the hypothalamic pituitary adrenocortical axis sustains epi secretion by the adrenal medulla
what is the target cell for adrenal medulla hormones?
most cells
what are the effects of adrenal medulla hormones?
->increase cardiac activity, blood pressure, glycogen breakdown, and blood glucose level and release of lipids by adipose tissue
where is the pancreas located?
behind stomach and beneath liver
pancreas has both ___ and ___
cells
exocrine and endocrine cells
endocrine cells of the pancreas are organized into__
islets of langerhans
what does islets of Langerhans secretes?
insulin and glucagon
insulin is produced by which cells of the islets?
beta cells
glucagon is produced by which cell of the islets?
alpha cells
exocrine cells of the pancreas secrete?
pancreatic juice and digestive enzyme
what is the action of insulin?
-> lowers blood glucose concentration
-> increased glucose uptake, storage and use by target cells
what is the target cell for insulin?
liver, muscle and fat cells
what is the action of glucagon?
-> it raises blood glucose concentration
->increases glycogen breakdown and glucose synthesis
what is the target cell of glucagon?
liver cells
what is the role of glucagon in carbohydrate metabolism?
->it stimulates hepatic glycogeneolysis which increases blood glucose
what is the role of glucagon in lipid metabolism?
->stimulates lipolysis which increases the release of free fatty acid and glycerol from adipose tissue
->increase hepatic ketogenesis and facilitates the conversion of fatty acids to keton bodes
what is the role of glucagon in protein metabolism?
-.has catabolic effect on hepatic protein and inhibit the incorporation of amino acids into hepatic protein
what is the role of insulin in carbohydrate metabolism?
-> lowers the level of blood glucose by increasing the transport and peripheral utilization of glucose
->increases muscle and liver glycogen
what is the role of insulin in protein metabolism?
-> strongly anabolic effect alew, it synthesizes protein and inhibit protein catabolism
-> increase the incorporation of a.a into protein by accelerating the entry of a.a into cells
what is the role of insulin in lipid metabolism?
-> inhibit the breakdown of triglycerides and stimulates the formation of triglycerides
->accelerates synthesis of fatty acids and glycerol phosphate and leading into increased deposition of triglycerides in adipose tissue
____is insulin excess
insulinoma
insulinoma results from?
adenoma of the islets
what is the treatment of insulinoma?
surgical removal of the tumor
____is deficiency of insulin
diabetes mellitus
define DM
a chronic disorder of carbohydrate, fat and protein metabolism
DM is characterized by?
hyperglycemia and commonly glycosuria which is sugar in urine
what’s the cause of DM?
relative or absolute deficiency of insulin
what is known as the most endocrine abnormality?
DM, it has 4% of incidence
type 1 and 2 DM onset
sudden
gradual
type 1 and 2 DM age at onset
any age
mostly in adults
type 1 and 2 DM body habitus
thin or normal
often obese
type 1 and 2 DM ketoacidosis
common
rare
type 1 and 2 DM autoantibodies
usually present
absent
type 1 and 2 DM endogenous insulin
low or absent
normal which is increased or decreased
type 1 and 2 DM concordance in identical twins
50%
90%
type 1 and 2 DM prevalence
less prevalent
more
what are the clinical signs of DM?
->polyuria which is huge urine output
->polydipsia which is excessive thirst
->polyphagia which is excessive hunger and food consumption
____is excessive insulin secretion
hyperinsulinemia which results in hypoglycemia
