15.3C: Onset, Duration, and Half-Life of Hormone Activity
- Page ID
- 7754
A hormone’s half-life and duration of activity are limited and vary from hormone to hormone.
- Distinguish between a hormone’s half-life and its duration of activity
Key Points
- The hormone receptors are dynamic structures that vary in number and sensitivity, that depend on the levels of the stimulating hormone.
- The blood levels of hormones reflect a balance between secretion and degradation/excretion by the liver and kidneys.
- The biological half- life of a hormone is the time it takes for the hormone to lose half of its physiological activity.
- The duration of hormone activity refers to the duration of altered cellular behavior triggered by hormone binding.
Key Terms
- hormone receptor: A molecule that binds to a specific hormone that triggers alterations in cell activity.
- half-life: The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacological, physiological, or radiological activity.
EXAMPLES
Vitamin D is a hormone that has a half-life of one to two months. If one obtains vitamin D solely through sun (UVB) exposure during the summer months, serum vitamin D levels will be critically low by late winter. This is one reason why current recommendations are to take vitamin D supplements in order to maintain serum vitamin D levels throughout the year.
The number of hormone molecules available for complex formation is usually the key factor that determines the level at which signal transduction pathways are activated. The number of hormone molecules that are available is determined by the concentration of circulating hormones.
Half-Life
The blood levels of hormones reflect a balance between synthesis/secretion and degradation/excretion. The liver and kidneys are the major organs that degrade hormones with breakdown products excreted in urine and feces.
A hormone’s half-life and duration of activity are limited and vary from hormone to hormone. For instance, the biological half-life of luteinizing hormone is 20 minutes, which is shorter than that of a follicle-stimulating hormone (three to four hours), and of human chorionic gonadotropin (24 hours).
A biological half-life or elimination half-life is the time it takes for a substance such as a hormone or drug to lose half of its pharmacologic or physiologic activity. In a medical context, half-life may also describe the time it takes for the blood plasma concentration of a substance to halve (plasma half-life) its steady-state.
The relationship between the biological and plasma half-lives of a substance can be complex, due to factors including their accumulation in tissues, active metabolites, and receptor interactions.
Duration
The duration of hormone activity refers to the duration of events that were stimulated by hormone-receptor binding. While typically relatively short and measured in minutes or hours, certain events, such as the onset of puberty, are much longer lasting.
Hormone levels during menstrual cycle: This image depicts the levels of certain hormones during the menstrual cycle (B), as they correspond to follicular growth and ovulation (A). 1. Follicle-stimulating hormone 2. Estrogen 3. Luteinizing hormone 4. Progesterone.
LICENSES AND ATTRIBUTIONS
CC LICENSED CONTENT, SHARED PREVIOUSLY
- Curation and Revision. Authored by: Boundless.com. Provided by: Boundless.com. License: CC BY-SA: Attribution-ShareAlike
CC LICENSED CONTENT, SPECIFIC ATTRIBUTION
- Second messenger system. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Second_messenger_system. License: CC BY-SA: Attribution-ShareAlike
- Nuclear receptor. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Nuclear_receptor. License: CC BY-SA: Attribution-ShareAlike
- secondary messenger. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/secondary%20messenger. License: CC BY-SA: Attribution-ShareAlike
- hormone response element. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/hormone%20response%20element. License: CC BY-SA: Attribution-ShareAlike
- nuclear receptor. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/nuclear%20receptor. License: CC BY-SA: Attribution-ShareAlike
- Second Messenger Mechanism. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:Second_Messenger_Mechanism.jpg. License: Public Domain: No Known Copyright
- Nuclear receptor action. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/File:Nuclear_receptor_action.png. License: Public Domain: No Known Copyright
- Receptor (biochemistry). Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Receptor_(biochemistry). License: CC BY-SA: Attribution-ShareAlike
- Target cell. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Target_cell. License: CC BY-SA: Attribution-ShareAlike
- endocrine action. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/endocrine%20action. License: CC BY-SA: Attribution-ShareAlike
- paracrine action. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/paracrine%20action. License: CC BY-SA: Attribution-ShareAlike
- target cell. Provided by: Wiktionary. Located at: en.wiktionary.org/wiki/target_cell. License: CC BY-SA: Attribution-ShareAlike
- Second Messenger Mechanism. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:Second_Messenger_Mechanism.jpg. License: Public Domain: No Known Copyright
- Nuclear receptor action. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/File:Nuclear_receptor_action.png. License: Public Domain: No Known Copyright
- Half-life. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Half-life%23Half-life_in_biology_and_pharmacology. License: CC BY-SA: Attribution-ShareAlike
- Hormone. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Hormone. License: CC BY-SA: Attribution-ShareAlike
- Endocrine gland. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Endocrine_gland. License: CC BY-SA: Attribution-ShareAlike
- Luteinizing hormone. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Luteinizing_hormone. License: CC BY-SA: Attribution-ShareAlike
- half-life. Provided by: Wiktionary. Located at: en.wiktionary.org/wiki/half-life. License: CC BY-SA: Attribution-ShareAlike
- hormone receptor. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/hormone%20receptor. License: CC BY-SA: Attribution-ShareAlike
- hormone. Provided by: Wiktionary. Located at: en.wiktionary.org/wiki/hormone. License: CC BY-SA: Attribution-ShareAlike
- Second Messenger Mechanism. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:Second_Messenger_Mechanism.jpg. License: Public Domain: No Known Copyright
- Nuclear receptor action. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/File:Nuclear_receptor_action.png. License: Public Domain: No Known Copyright
- Hormons level - follicle & corpus luteum. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/Fi...pus_luteum.svg. License: CC BY-SA: Attribution-ShareAlike