It is called a basophil because it readily takes up base, and typically stains a relatively deep blue or purple.
These basophils are further classified by the hormones they produce. (It is usually not possible to distinguish between these cell types using standard staining techniques.)
| Cell name | Relative proportion | Hormone produced | Hypothalamic regulators |
| Corticotrophs | 15% | ACTH | CRH |
| Gonadotrophs | 10% | FSH and LH | GnRH |
| Thyrotrophs | 5% | TSH | TRH |
B-FLAT for Basophils: FSH, LH, ACTH, TSH