Hormones are chemical messengers that tell your cells what to do. They control everything from growth, metabolism, and mood, to reproduction, sleep, and stress response. But where do hormones come from? How are they made? And what determines how they work?
Let’s dive into the fascinating world of hormone biosynthesis — where biology meets chemistry.
📚 First: What Are Hormones?
Hormones are signaling molecules secreted by glands into the bloodstream to regulate body functions. They act at a distance — made in one tissue, acting on another.
There are three main classes of hormones:
Each type is synthesized differently depending on its molecular origin.
🧪 1. Peptide Hormones: Made in the Ribosome
These are protein-based hormones. Their synthesis looks a lot like how your body makes any protein:
🧬 Steps:
- Gene Activation – DNA in the nucleus is transcribed to mRNA.
- Translation – mRNA is read by ribosomes to make a precursor protein (preprohormone).
- Processing – The preprohormone is cleaved into a prohormone and then the active hormone.
- Storage & Release – The finished hormone is stored in vesicles and released in response to signals.
🧠 Examples:
- Insulin (regulates blood sugar)
- Oxytocin (social bonding)
- ACTH (stimulates cortisol release)
🧪 2. Steroid Hormones: Made from Cholesterol
Steroid hormones are lipid-based, meaning they’re fat-soluble and can easily pass through cell membranes.
🧬 Steps:
- Cholesterol Uptake – Cells take in cholesterol from LDL particles or synthesize it.
- Enzymatic Conversion – Specialized enzymes (like CYP450s) convert cholesterol into hormones.
- Tissue-Specific Pathways – Depending on the gland, cholesterol becomes:
- Cortisol in the adrenal cortex
- Testosterone in the testes
- Estrogen in the ovaries
- Cortisol in the adrenal cortex
Steroid hormones are not stored — they are made on demand and diffuse directly into the bloodstream.
🧪 3. Amine Hormones: Modified Amino Acids
These small hormones are made by modifying a single amino acid, usually tyrosine or tryptophan.
🧬 Steps:
- Tyrosine → dopamine → norepinephrine → epinephrine (adrenaline)
- Tryptophan → serotonin → melatonin
These hormones are often stored in vesicles and released in bursts during stress, sleep cycles, or emotional changes.
🔄 What Regulates Hormone Production?
Hormone synthesis is tightly regulated by feedback loops, mostly involving the hypothalamus-pituitary axis.
- Negative feedback keeps hormone levels in check.
E.g. High cortisol → signals pituitary to reduce ACTH. - Circadian rhythms influence hormones like melatonin and cortisol.
- Nutritional and cofactor status also matter:
- Vitamin B6 – needed for serotonin and GABA synthesis
- Cholesterol – required for all steroid hormones
- Vitamin B6 – needed for serotonin and GABA synthesis
Iron, copper, zinc, magnesium – essential enzyme cofactors
🧩 Recap: Hormone Synthesis at a Glance
🧠 Final Thoughts
Hormones are more than just chemicals — they’re your body’s communication network. Each hormone begins as a simple molecule, shaped by enzymes, nutrients, and genetic instructions, and transformed into a powerful signal that keeps your body in balance.