Explanation

Second messengers are molecules that relay signals received at receptors on the cell surface-such as the arrival of protein hormones, growth factors etc to larger in the cytosol or nucleus. The major second messengers are $c$AMP, $c$GMP, ${IP}_{3}$,DAG and ${Ca}^{2 +}.$ $c$AMP is not involved as second messenger in ${Ca}^{2 +}$ mediated hormone action.