Virtually all of the protein or amino acid-based hormones exert their effects through intracellular ________. Naim 06:24 The Endocrine System Virtually all of the protein or amino acid-based hormones exert their effects through intracellular ________. A) ions B) deactivators C) nucleotides D) second messengers Answer: D Learn More : Share this Share on FacebookTweet on TwitterPlus on Google+