The pituitary_gland ("master gland of the endocrine system") is located in the sella_turcica of the sphenoid bone. It is connected to the hypothalamus by a stalk called the infundibulum, and is divided into two sections: the anterior_pituitary, which is also known as the adenohypophysis and the posterior_pituitary, which is often called the neurohypophysis.

The anterior pituitary secretes a number of hormones, four of which are tropic, (a/k/a trophic):

(1) Lutenizing_hormone (LH),

(2) Follicle-stimulating_hormone (FSH),

(3) Adrenocorticotropic_hormone (ACTH). and

(4) Thyroid-stimulating_hormone (TSH).

Two other anterior pituitary hormones are non-tropic:

(1) Growth_hormone (GH) and

(2) Prolactin (PRL).

Acidophils produce prolactin and growth hormone. The acidophil is known as a chromophil_cell, which means it is a cell that readily acquires stain. Acidophils have a dark nucleus and pink/red cytoplasm.

Basophils produce the tropic (trophic) hormones, including adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), Follicle-stimulating hormone (FSH), and lutenizing hormone (LH). Basophils are also chromophil cells. Basophils have a dark blue nucleus and cytoplasm.

Chromophobes are still under investigation. Electron microscope studies have revealed that they have active secretory granules. Recent information suggests they may be degranulated chromophil cells. The nucleus of a chromophobe acquires dark blue stain, but the cytoplasm remains clear or a very sheer, pale blue.