fig1

Figure 1. Top: endocrine pancreas, the alpha cell releases glucagon; it is turned off by GABA co-released with insulin from beta cells. In this way when anabolic insulin is ON catabolic hormones are OFF, GABA also inhibits epinephrine release from adrenals. Moreover, GABA turns off somatostatin release from delta cells, which stimulates growth hormone and IGF. The cell below the pancreas displays different metabolic finalities that can be reached; these are controlled by a few “switch compounds” themselves controlled by the endocrine pancreas. These compounds are listed in the boxes below the cell. The yellow pathways represent the nutrition finality forming glucose and ketone bodies; it is activated by catabolic hormones that control the switch compounds in the yellow box (+ is increase, - decrease, 0 no change or not relevant). The second and third metabolic finalities represented by the red pathways is the production of energy from glucose, in the case of glucagon or insulin, note in the corresponding red boxes the difference for diacylglycerol DAG. The next finality is the production of energy from fatty acids it is represented by the black pathways and the black box for switch compounds. The last finality represented by the green pathways and green box for the switches, is the anabolic synthesis of new constituents, it is essential for mitotic cells. The last box in brown shows for comparison the switches for mitotic tumor cells, specially studied in Figure 2. DAG: diacyl glycerol; PK: pyruvate kinase; PDH: pyruvate dehydrogenase; GH: growth hormone