islets of Langerhans

clusters of cells within the PANCREAS , which are the ENDOCRINE part of the gland. There are three types of cells, termed alpha, beta and delta, the first two producing GLUCAGON and INSULIN respectively, both vital hormones in the regulation of BLOOD-SUGAR levels. The third hormone produced is somatostatin (also released by the HYPOTHALAMUS ), which works antagonistically against GROWTH HORMONE by blocking its release by the PITUITARY GLAND . The islets were named after Paul Langerhans, a German pathologist.