30 Questions
What is the primary function of oxytocin?
Stimulating uterine contractions and milk ejection
What is another name for vasopressin?
Antidiuretic hormone (ADH)
What is the name of the molecule that regulates skin pigmentation, among other functions?
Proopiomelanocortin (POMC)
Which of the following cell types secretes growth hormone?
Somatotropes
What is the name of the hormones secreted by the intermediate lobe of the pituitary?
Melanocyte-stimulating hormones (MSHs)
How many types of secretory cells have been identified in the anterior pituitary?
5
What is the primary source of hGH-V and hCS in the circulation?
Placenta
What percentage of circulating growth hormone is in the bound form?
50%
What is the normal range of basal plasma growth hormone levels in adult humans?
Less than 3 ng/mL
What is the half-life of circulating growth hormone in humans?
6-20 minutes
What is the daily growth hormone output in adults?
0.2-1.0 mg/d
What is the location of the growth hormone-hCS cluster in humans?
Long arm of human chromosome 17
How many genes are present in the growth hormone-hCS cluster?
5
What is unique about the growth hormone receptor's binding mechanism?
It binds to one receptor, attracting another to form a homodimer
What is the function of hGH-V?
It codes for the variant form of growth hormone
What is the result of posttranslational modifications of hGH-N?
A complex mixture of peptides with varying degrees of glycosylation
What is the challenge in assaying for each growth hormone species separately?
Their structural similarities make it difficult to assay
What is the emerging evidence about the functions of the various peptides?
They occasionally exert actions in opposition to one another
What is the essential process for receptor activation?
Dimerization
What is the effect of hypophysectomy on growth in young animals?
Growth is inhibited
What is the name of the pathway activated by growth hormone, which involves cytoplasmic tyrosine kinases and transcription factors?
JAK-STAT pathway
What is the result of prolonged treatment with growth hormone in animals with closed epiphyses?
Acromegaly
What is the role of STATs in the JAK-STAT pathway?
Cytoplasmic transcription factors
What is the effect of growth hormone on the sizes of most viscera?
They are increased
What is the indirect way growth hormone promotes growth?
By increasing the ability of the pancreas to respond to insulinogenic stimuli
What is the name of the first somatomedin isolated?
Sulfation factor
What is unique about the C chains of insulin-like growth factor I (IGF-I) and IGF-II?
They are not separated
What is the effect of insulin on protein metabolism?
It has a protein anabolic effect
What is the function of somatomedins?
Promote protein anabolism and collagen formation
Which of the following is not a somatomedin?
Glucagon
Learn about the hormones oxytocin and vasopressin, their functions, and how they are released into the bloodstream. Understand the role of the hypothalamus in hormone secretion.
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