Endocrine Glands and Hormone Classes (3A) Practice Test
•15 QuestionsInvestigators examined a lipid-soluble hormone secreted by an endocrine gland located atop the kidneys. In healthy volunteers, an intravenous infusion of this hormone for 30 minutes increased expression of epithelial Na$^+$ channels in distal nephron cells and was followed by a gradual rise in arterial pressure over 2 hours. When arterial pressure rose, secretion of the hormone decreased.
A separate arm used a competitive antagonist that prevented the hormone–receptor complex from binding DNA response elements. Plasma electrolyte data are shown:
Condition | Plasma Na$^+$ (mM) | Plasma K$^+$ (mM)
Baseline | 140 | 4.2
Infusion | 143 | 3.6
Infusion + DNA-binding antagonist | 140 | 4.2
Based on the vignette, which outcome is most consistent with this hormone class’s mechanism of action?
Investigators examined a lipid-soluble hormone secreted by an endocrine gland located atop the kidneys. In healthy volunteers, an intravenous infusion of this hormone for 30 minutes increased expression of epithelial Na$^+$ channels in distal nephron cells and was followed by a gradual rise in arterial pressure over 2 hours. When arterial pressure rose, secretion of the hormone decreased.
A separate arm used a competitive antagonist that prevented the hormone–receptor complex from binding DNA response elements. Plasma electrolyte data are shown:
Condition | Plasma Na$^+$ (mM) | Plasma K$^+$ (mM) Baseline | 140 | 4.2 Infusion | 143 | 3.6 Infusion + DNA-binding antagonist | 140 | 4.2
Based on the vignette, which outcome is most consistent with this hormone class’s mechanism of action?