This document is from the Division of Endocrinology and Metabolism at the University of Sebelas Maret in Surakarta, Indonesia. It is a lecture on endocrinology topics that includes sections on hormones, the PIP-calcium signal mechanism, steroid hormones and direct gene activation, and the central nervous system's modulation of hormone release. The document is a 47-slide lecture presented by Dr. Djoko Hardiman on various topics within the field of endocrinology.