Also known as the growth-hormone-release-inhibiting factor, this is a hormone secreted by the HYPOTHALAMUS and some non-nervous tissues (including the gastrointestinal tract and pancreas). It stops the pituitary from releasing somatotrophin – GROWTH HORMONE. Somatostatin and growth-hormone-releasing hormone are controlled by complicated neural mechanisms linked to exercise, sleep patterns, stress, NEUROTRANSMITTERS and blood GLUCOSE.