College of Massage Therapists of British Columbia (CMTBC) Practice Exam

What characteristic is true about water-soluble hormones?

1. They have a longer half-life in the bloodstream

2. They are less easily absorbed and excreted

3. They are more easily absorbed and excreted

4. They can pass through cell membranes easily

The correct answer is: They are more easily absorbed and excreted

Water-soluble hormones, such as peptide and protein hormones, have a unique characteristic when it comes to their interaction with the bloodstream and cellular membranes. They are indeed more easily absorbed and excreted compared to fat-soluble hormones. This is largely due to their chemical structure, which allows them to dissolve in water. In the bloodstream, water-soluble hormones circulate freely without the need for carrier proteins, making them readily available to the target cells. When they reach their target, these hormones bind to specific receptors on the cell surface rather than passing through the lipid-based cell membranes. This binding triggers a series of cellular responses through secondary messengers, leading to a quicker activation of their physiological effects. Additionally, because water-soluble hormones are not stored in the body for long periods, they have a shorter half-life compared to fat-soluble hormones. This means they can be rapidly synthesized and released as needed, allowing the body to quickly respond to changes in physiological demands. Understanding the nature of water-soluble hormones is essential for comprehending how hormonal regulation works within the body, particularly in rapid response situations, such as stress or metabolic changes.