autacoids are substances with diverse physiological & pharmacological activities which are grouped together mainly as they participate in physiological & pathophysiological responses to injury.
they cannot be classed as hormones or neurotransmitters & as they usually have a brief lifetime & act near their sites of synthesis, they are often described as local hormones, but true hormones reach their site of action via the bloodstream hence the term used is autacoid (Greek derivation for “self-remedy”).
substances that are secreted by specialised cells to act primarily on neighbouring cells such as somatostatin & gastrin are referred to as paracrine hormones & are not included as autacoids