Local Hormones

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Most hormones are circulating hormones. They pass from the secretory cells into interstitial fluid and then into the blood. Local hormones, act locally on neighboring cells (paracrines) or on the same cell that secreted them (autocrines) without entering the bloodstream For example, somatostatin secreted by delta cells of pancreatic islets diffuses through tissue fluid and acts on the neighbouring alpha and beta cells.