Pituitary Glands Flashcards
According to FSH and LH
there are two types of disorder in releasing of these hormones.
1-Primary –> the deFect on testes
2. Secondary —> defect on anterior Pituitary that lead tp decrease of production pf LH&FSH
Whats considered as Posterior Feedback Mechanism
So body sends signals for hypothalmus to produce LHRH &FSRH
Negative Feedback Mechanism
Example + moa
Thyroxine
if its level is high in body —>body gives signal for pituitary to decrease corticatropin hormone production
But if there’s an tumor in pituitary this may lead to increase in production of thyroxine hormone, then increase both T4 and T3 level, then there’s a problem
Increase in production due to hypersensitivity to other hormones like
if there’s B hypersensitivity, to TSH —>The production f T4 will increase as we can see in Thyrotoxicosis disease.
Growth Hormone (Somatotropin) prevalence
GH increase highly in the adolscence period and may be absent neonatal and adult period.
Note: Increase in GH may lead to DM - explain
One to increase the insulin resistance and hypoglycemic effect when patient taking carbohydrates
Growth hormone excess lead to
Acromegally –> insidious cosymptomatic disorder
What occurs during Benign pituitary Tumor
In Benign pituitary Tumor there is an increase in size of production cells of gonadtropins which are gonadotrophes cells which finally lead to increase in GH production
When does Acromegaly Occur?
Acromegaly usually occurs after fusion of epiphysis (growth plate) of the long bones
Whats the difference between Acromegaly and Gigantism?
Gigantism occurs before epiphysis (epiphysis closure) - then theres an increase in height, length of arms, legs to abnormal level.
IGF-I location and whats it stimulated by
IGF-I produced in the liver and t’s production is stimulated by the GIT
What’s IGF-I ?
IGF-I is the hormone that goes to body organs ( heart, bone, etc.) and act as a function of GIT.
GH can also be increased by stress
True
Diagnosis of Acromegaly
MRI and CT scan
Goal of Management for Acromegaly
1- Normalize biochemical marker ( blood sugar level which increases with GH increase, cholesterol, etc.)
2- Reduce tumor size ( as in edema)
3- keep normal pituitary function, improve clinical function
4-Decrease in mortality rate, morbidities
Acromegaly associated with high mortality , why?
This may be due to its enlargemnt of heart and other agents or vessels
Treatment for Acromegaly
When surgery is impossible
1- Somatostatin–>hormone that go to the hypothalmus and prevent GHRH
2- Dopamine act inversely with GH- Dopamine Antagonists
*Surgery - removing a part of pituitary gland- patients may suffer from hypopituitarism.
3- Dopamin Agonists ( Cabergoline=dostinex)
4- GH receptor Antagonists
5-Radiation Therapy ( radiation=Hypothyroidism
For patients with increase in both GH & Prolactin, the treatment is
by Bromocriptine or Carbegoline can be beneficial for Acromegaly.
Laboratory test- according to MRI and CT scan
1) Patient older than 1 year (x-ray: left wrist and hand)
2) Patient younger than 1 year( x-ray: knee and ankle)
If there’s an increase in prolactin level
Hyperprolactinemia
Anti-dopamine
can increase prolactin like domperidone
Pathophysiology of Hyperprolactinemia
High level of prolactin –> Inhibition of GnRh
During breast feeding, prolactin level will increase –>inhibition of of GnRh —>decrease both LH &FSH= No ovulation or spermatogenesis.
Prolactin Treatment
1- Normalize prlactin level, because like we said prolactin is toxic for GnH, also it can cause skin problems, uscle and others.
Primary vs Secondary
Primary- defect in primary target organ
Secondary- defect in pituitary gland
