LOCAL HORMONES

SYNTHESIS OF LOCAL HORMONES

• Local hormones are synthesized at the site of action and act on nearby cells (paracrine action) or the same cell that secretes them (autocrine action).

• They are produced by various tissues rather than specific endocrine glands.

• Most local hormones are derived from fatty acids (eicosanoids) or peptides.

• Their synthesis is usually triggered by stimuli like injury, infection, or physiological stress.

TYPES AND FUNCTIONS OF LOCAL HORMONES

• PROSTAGLANDINS – Regulate inflammation, pain sensation, fever, blood clotting, and smooth muscle contraction. Important in labor, digestion, and immune responses.

• LEUKOTRIENES – Mediate allergic and inflammatory responses, especially in asthma and immune system regulation.

• THROMBOXANES – Promote blood clotting and vasoconstriction to control bleeding.

• NITRIC OXIDE (NO) – Acts as a vasodilator, relaxing blood vessels and improving blood flow. Also involved in neurotransmission and immune defense.

• HISTAMINE – Released by mast cells during allergic reactions, causing swelling, itching, and vasodilation.

• CYTOKINES – Regulate immune responses, inflammation, and cell communication. Examples include interleukins and interferons.

• ENDORPHINS – Act as natural painkillers and mood enhancers by inhibiting pain signals in the nervous system.