which type of hormone requires a second messenger
Examples of second messenger molecules include Cyclic AMP, Cyclic GMP, Inositol Triphosphate, Diacylglycerol, and Calcium. The cell releases second messenger molecules in response to exposure to extracellular signaling molecules-the first messengers. First messengers are extracellular substances that include peptide hormones such as epinephrine, growth factors, neurotransmitters such as serotonin and steroid hormones.