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Львівський національний медичний університет ім. Данила Галицького
Кафедра променевої діагностики і терапії
«ЗАТВЕРДЖУЮ»
Зав. кафедри променевої
діагноститки і терапії
Обговорена і затверджена на
доц. Дац І.В.
методичному засіданні кафедри
"_____"_______________ 200 р
Наказ № ________________
Лекція № 5
Назва
RADIONUCLIDE METHODS IN ENDOCRINOLOGY. RPL’S WHICH ARE USED
FOR EVALUATION OF THYROID GLAND. ASSESSING OF THE THYROID GLAND
FUNCTION BY MEANS OF I131, TC99M -INTAKE TESTS. RADIOIMMUNOASSAY –
ESTIMATION OF T3, T4, TTH. RADIONUCLIDE VISUALISATION OF THE THYROID
GLAND: SCANNING, SCINTIGRAPHY. DIAGNOSTIC ALGORITHM OF THYROID
GLAND, DIAGNOSTIC VALUE.
Лекцію підготувала ас. Шатинська-Мицик І.С.
Львів
Functional types of hormones:
a. Releasing factors from the hypothalamus which stimulate anterior pituitary
b. Inhibitory hormones - from the hypothalamus or GIT (suppress the secretion of particular
hormones).
c. Tropic hormones - come from the anterior pituitary gland and have as a target the other endocrine
glands.
d. Non-tropic or effector hormones
 secreted by non-pituitary endocrine glands
 act on tissue cells
 stimulate a feedback effect upon hypothalamus or anterior pituitary glands
a) Negative feedback: an increase in the product causes a decrease in the system
b) Positive feedback: an increase in the product causes an increase in the activity of the system
a. Primary control = hypothalamus (small gland adjacent to the pituitary gland & connected to it
via “pituitary stalk”
 synthesize ADH (vasopressin) and oxytocin
b. Secondary control- pituitary gland:
Lobes: posterior lobe = neurohypophysis, anterior lobe = adenohypophysis
 Tropic hormones secreted: ACTH, TSH, FSH, LH
 Effector hormones secreted: GH (somatotropin), Prolactin
I. Anterior Pituitary Hormones:
1. Growth hormone (GH) (Somatotropin):
-men: <5 ng/ml
-women: <10 ng/ml
-child: 0-10 ng/ml, newborn: 10-40 ng/ml
 Causes production of somatomedians (peptides secreted by the liver which act as second
messengers)
 Have insulin-like activity in some tissues
▲ Increased Levels:
 Gigantism
 Acromegaly
 Anorexia nervosa. Starvation stimulates GH secretion.
Stress, surgery, hypoglycemia, starvation, exercise
 Deep-sleep state
▼ Decreased Levels:
 pituitary insufficiency due to tumors, ischemia, or trauma
 dwarfism. This is a result of GH deficiency in children.
 hyperglycemid,- elevated glucose levels inhibit GH secretion.
 delayed sexual maturity.
2. Prolactin (PRL)
Function–breast growth during pregnancy and milk secretory activity
Major use of determination is to assist in the diagnosis of pituitary tumors
Measurement by RIA: male: 0-20ng/ml; women 0-25ng/ml, pregnant: 20-400 ng/ml
Increased levels in:
 Galactorrhea
 Amenorrhea
 Prolactin-secreting pituitary tumors
 Hypothyroiditis
 Paraneoplastic syndrome
 Stress (anorexia)
 Empty sella syndrome
 Polycystic ovary syndrome
 Renal failure
Decreased levels in:
 Pituitary apoplexy (Sheehan’s syndrome)
 Pituitary destruction by craniopharyngeoma
3. TSH:
 for neonatal screens
 confirming adult hypothyroidism
4. ACTH adrenocorticotropic hormone=corticotropin:
 target cells–adrenal cortex
 stimulate production of adrenal steroids
 has diurnal variation:
-highest level occurs between 6-8am
-lowest level occurs between 6-11pm
Normal Findings: AM: <80 pg/ml or <18 pmol/L (SI units) PM: <50 pg/ml or <11 pmol/L (SI
units)
Indications:
The serum ACTH study is a test of that affords to differentiate the causes of either Cushing's
syndrome (overproduction of cortisol) or Addison's disease (underproduction of cortisol).
Corticotropin-releasing hormone (CRH) is made in the hypothalamus. It stimulates ACTH
production in the anterior pituitary gland, which in turn stimulates the adrenal cortex to produce
cortisol. The rising levels of cortisol act as a negative feedback mechanism and curtail further
production of CRH and ACTH.
In the patient with Cushing's syndrome an elevated ACTH level can be caused by:
 a pituitary ACTH-producing tumor
 a nonpituitary (ectopic) ACTH-producing tumor, usually in the lung, pancreas, thymus, or
ovary. ACTH levels over 200 pg/ml usually indicate ectopic ACTH production.
 If the ACTH level is below normal in a patient with Cushing's syndrome, an adrenal
adenoma or carcinoma is probably the cause of the hyperfunction.
 In patients with Addison's disease an elevated ACTH level indicates primary adrenal gland
failure, due to infarction, hemorrhage, or autoimmunity; surgical removal of the adrenal
gland; congenital enzyme deficiency; or adrenal suppression after prolonged ingestion of
exogenous steroids.
 If the ACTH level is below normal in a patient with adrenal insufficiency, hypopituitarism
is most probably the cause of the hypofunction.
 Diurnal variation is lost when disease (especially neoplasm) affects the pituitary or adrenal
glands.
 ACTH is measured in amniotic fluid when anencephaly is suspected. Decreased levels are
noted in anencephalic fetuses.
Interfering Factors:
 Stress (trauma, pyrogen, hypoglycemia), menses, and pregnancy cause increased levels of
cortisol. This is accomplished through elevation of ACTH.
 Drugs that may cause increased levels include estrogens, ethanol, vasopressin, amphetamines,
insulin, levodopa, and spironolactone.
 Exogenously administered corticosteroids decrease ACTH levels.
Table 1: Cortisol ACTH Levels in Diagnosis of Adrenal Dysfunction
Disease
Cortisol
ACTH
Cushing's syndrome
High
low

Adrenal micronodular hyperplasia

Adrenal tumor (adenoma, cancer)
Cushing's syndrome
High
High

Cushing's disease (ACTH-producing pituitary tumor)

Ectopic ACTH-producing tumor (e.g., lung cancer)
Addison's disease
low
...

Adrenal gland failure (e.g., infarction, hemorrhage,

congenital adrenal hyperplasia)
Plik z chomika:
misiek-puchatek
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