Exam 5 Review: Chapter 16: Endocrine Effects
amplification (endocrine) - The term used to describe the multiplier effect (“domino effect” or “snowball effect”) observed when a single molecule of hormone interacts with its target receptor and that interaction triggers the formation of several molecules of activated second messenger and each molecule of activated second messenger is capable of activating multiple copies of the catalysts of the biochemical pathway(s) which produce the cellular effect generated by the command from the original hormone.enzyme cascade - Enzyme cascades are key to the amplification of many target cell responses to control systems such as hormonal regulation; under normal conditions, all of the proteins in each of the cascades are in a non-active form; the cascade begins with the activation of the first protein in the cascade by a second messenger, the first activated enzyme then enzymatically activates the next, and so on, until numerous products result; in addition, products of one cascade can cause further amplification by activating proteins in the other cascades.
permissive effect - If a cell receives instructions from two (or more) hormones at the same time, the first hormone's presence is necessary for the second hormone to produce its effect; e.g., epinephrine cannot change cellular energy consumption unless thyroid hormones are present in normal concentrations so the thyroid hormones exert the permissive effect.
synergistic effect - If a cell receives instructions from two (or more) hormones at the same time, the two (or more) hormones have additive effects and the net result of stimulation is greater than each would produce if it acted alone; e.g., an additive effect.
antagonistic effect
- If a cell receives instructions from two (or more) hormones at the same
time, the effects will be weaker than those produced by either hormone if it
acted alone, and often the response of the target is to be stimulated by one
member of the pair and inhibited by the other; e.g., the antagonistic effects of
insulin and glucagon on blood glucose levels.
1.