3. Hypothalmic-Pituitary Relationships Flashcards
What 2 things are secreted by the majority of the cell bodies in the supraoptic nuclei?
Antidiuretic hormone (ADH).
Neurophysin II.
What is the elementary precursor for oxytocin?
What is the elementary precursor for ADH?
Preprooxyphysin.
Prepropressophysin.
Recall the pathway for GH regulation and check it against the pathway on the reverse.
What is more important for the regulation of ADH, blood volume or osmolarity?
Osmolarity. Only a 1% change is required to cause an effect, whereas a 10% change in blood volume is necessary.
What is released by a lactotroph?
What hypothalamic hormone triggers its release?
Prolactin.
TRH.
How does growth hormone promote growth?
What specific cell type is responsible for growth hormone’s effect on bones?
Increases protein synthesis (organ growth).
Increases uptake of amino acids.
Stimulates synthesis of DNA, RNA, and new proteins.
Increases metabolism in and proliferation of chondrocytes.
Chondrocytes are responsible for growth hormone’s effect on bones.
What cell population does corticotropin-releasing hormone act upon?
What hormone is ultimately released as a result?
Corticotrophs.
ACTH
How might damage to the pituitary gland cause diabetes insipidus?
Damage to the cells which release antidiuretic hormone.
How can we differentiate between central vs. nephrogenic diabetes insipidus?
In central diabetes insipidus ADH will be low, and patient will respond to desmopressin.
In nephrogenic diabetes insipidus, ADH will be high and patient will not respond to desmopressin.
What are the diabetogenic effects of growth hormone?
Causes insulin resistance.
Decreases tissue glucose uptake and utilization.
Increases lipolysis and adipose tissue.
Results in increased blood insulin levels (which causes the insulin resistance).
What are the three families of anterior pituitary hormones?
The ACTH family.
The FSH, LH, and TSH (FLaT) family.
Prolactin and GH family.
What molecule mediates growth hormone’s growth effects?
Somatomedins.
What cells of the hypothalamus produce the most oxytocin?
Cells of the paraventricular nucleus.
What is affected in a primary / secondary / tertiary endocrine disorder respectively?
Primary disorder: peripheral endocrine gland defect.
Secondary disorder: pituitary gland defect.
Tertiary disorder: hypothalamus defect
Why do we look at IGF-I levels when suspecting a diagnosis of acromegaly?
Because growth hormone leads to the secretion of IGF-I, which should then inhibit growth hormone secretion. If both growth hormone secretion and IGF-I secretion are high, something else is stimulating growth hormone secretion.
Also, growth hormone levels can fluctuate throughout the day, whereas IGF-I levels remain constant.