All Available Questions
Which of the following statements concerning a particular hormone (hormone X) is correct?
a. It will bind to cell membrane receptors in all cell types.
b. It is lipid soluble and has an intracellular receptor.
c. It circulates bound to a protein, and this shortens its half-life.
d. It is a small peptide; therefore, its receptor localization will be in the nucleus.
Hormones bind to specific receptors in their target cells. Lipid-soluble hormones bind to intracellular receptors. Hormone binding to binding proteins increase their half-life. Peptide hormones bind to cell membrane receptors. Thyroid hormones are the only nonsteroid hormones that bind to intracellular receptors. They are transported into the cell.
Which of the following would be expected to alter hormone levels?
a. Changes in mineral and nutrient plasma levels
d. Training for the Olympics
Changes in mineral and nutrient plasma levels (eg, calcium or glucose) affect hormone release. Pituitary tumors can result in either deficient or excessive hormone production. Transatlantic flight can disrupt circadian rhythms affecting hormone release. Strenuous exercise (as in training for the Olympics) is associated with decreased gonadotropinreleasing
hormone (GnRH) release.
Which of the following statements concerning hormonal regulation is correct?
a. A hormone does not inhibit its own release.
b. The substrate a hormone regulates does not affect that hormone’s release.
c. Negative feedback regulation occurs only at the level of the anterior pituitary.
d. Feedback inhibition may be exerted by nutrients and hormones.
Hormones may inhibit their release through an autocrine mechanism. The substrate a hormone regulates (eg, calcium or glucose) directly regulates release of insulin and parathyroid hormone. Negative feedback regulation can occur at the level of the organ releasing the hormone, at the pituitary or in the hypothalamus. Feedback inhibition may be exerted by nutrients (calcium) and hormones (cortisol).
The structure of a newly discovered hormone shows that it is a large peptide with a glycosylated subunit. The hormone is likely to:
a. Bind to DNA and affect gene transcription