Biochem 23: Hormonal Regulation and Integration of Mammalian Metabolism

By now, Medlock Holmes has followed dozens of pathways — branching, converging, competing. In this final episode of Bioenergetics & Metabolism, he steps back to ask the only question that now matters: who decides?Hormonal regulation is revealed as the quiet authority that integrates metabolism into a coherent, organism-wide response. Insulin, glucagon, adrenaline, cortisol — these are not mere messengers, but conductors, ensuring that tissues act in concert rather than conflict. A liver storing glucose while muscle demands it would be chaos. Hormones prevent that.Drawing on the integrative systems view of Lehninger Principles of Biochemistry and the clinically grounded framing of endocrine action in Harper’s Illustrated Biochemistry, this episode shows how fed and fasted states are coordinated, how short-term stress overrides long-term planning, and how metabolic priorities shift with context.Medlock learns that regulation is not about maximising one pathway. It is about choosing which sacrifice is acceptable at any given moment. Disease, here, is not a broken reaction — it is a failure of integration. Too much signal. Too little response. Or the wrong message, delivered at the wrong time.With this episode, metabolism ceases to be a map of reactions and becomes a living strategy.Key Topics Explored* Hormonal control of metabolic pathways* Fed versus fasted state integration* Tissue-specific metabolic priorities* Insulin, glucagon, and counter-regulatory hormones* Short-term versus long-term metabolic decisions* Clinical relevance: diabetes, metabolic syndrome, endocrine disease This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe