• the source of somatostatin growth inhibitory hormone is same as that of
• thyroxine and calcitonin
• insulin and gulcagon
• somatotrophin and prolactin
• adh and oxytocin

The source of somatostatin which is also known as growth hormone inhibiting hormone is same as that of insulin and glucagon. It is because insulin, glucagon and somatostatin are secreted by beta, alpha and delta cells of pancreas respectively.