Somatotroph. Coloured transmission electron micrograph of a growth hormone-producing cell from the pituitary gland. The pituitary gland or hypophysis is located at the base of the brain. Here, a growth hormone-secreting endocrine cell, known as a somatotroph, is shown. The hormone is in the numerous granules within the cell cytoplasm. Visible cell organelles include mitochondria and the nucleus with its chromatin. There are large amounts of rough endoplasmic reticulum with the protein-synthesizing ribosomes. Magnification: x6000 when printed at 10 centimetres wide.