Pituitary gland. Coloured transmission electron micrograph (TEM) of cells in the anterior pituitary gland, a hormone-secreting gland at the base of the brain. The cells' nuclei, which contain their genetic information, are brown. The cell at top left is a somatotroph cell, while the cell at bottom right is a gonadotroph cell. Both cells are secretory cells and have granules (purple) containing hormones to be secreted in their cytoplasm (pink). Somatotrophs secrete human growth hormone, which promotes growth and controls numerous metabolic processes. Gonadotrophs secrete leutinising hormone and follicle-stimulating hormone, which affect the ovaries or testis and regulate reproductive function.