The most popular way to remember the anterior pituitary hormones is the mnemonic FLAT PeG, where each letter stands for one of the seven hormones this gland produces: FSH, LH, ACTH, TSH, Prolactin, Endorphins, and Growth Hormone. But a mnemonic alone only gets you a list. To actually retain these hormones for an exam or clinical practice, it helps to understand what each one does, how they’re grouped, and how the hypothalamus controls them. Those logical connections make the mnemonic stick.
The FLAT PeG Mnemonic
Here’s what each letter represents:
- F = Follicle-Stimulating Hormone (FSH)
- L = Luteinizing Hormone (LH)
- A = Adrenocorticotropic Hormone (ACTH)
- T = Thyroid-Stimulating Hormone (TSH)
- P = Prolactin
- e = Endorphins
- G = Growth Hormone (GH)
Some courses teach only six hormones and drop endorphins from the list, since endorphins are a byproduct of the same precursor molecule that produces ACTH rather than a standalone hormone with its own dedicated cell type. If your class uses a six-hormone list, you can shorten the mnemonic to FLAT PG. Either way, the core six (FSH, LH, ACTH, TSH, Prolactin, GH) are the ones you’ll be tested on most.
Group Them by Function
Memorizing a list of seven items is harder than memorizing two or three small groups. The anterior pituitary hormones split neatly into two categories: tropic hormones that boss other glands around, and direct hormones that act on tissues themselves.
Tropic Hormones
Four of the six main hormones are tropic, meaning their job is to tell another endocrine gland to release its own hormones. Think of them as middle managers. ACTH tells the adrenal glands to produce cortisol and other stress hormones. TSH tells the thyroid to release T3 and T4, which regulate metabolism and energy. FSH and LH, collectively called the gonadotropins, tell the ovaries or testes to produce sex hormones, drive ovulation, and support sperm production. Notice that three of the four tropic hormones have “stimulating” right in the name, which is a built-in reminder of what they do.
Direct Hormones
Growth hormone and prolactin act on tissues directly rather than commanding another gland. Growth hormone promotes growth in nearly every tissue and organ in the body, especially during adolescence. It also triggers the liver to produce a secondary growth signal. Prolactin stimulates breast tissue development and milk production. A simple way to remember the split: the two “simple name” hormones (growth hormone, prolactin) are the direct ones. The four with long, compound names are the tropic ones.
Connect Each Hormone to Its Hypothalamic Trigger
The anterior pituitary doesn’t act on its own. The hypothalamus sits just above it and sends releasing hormones through a dedicated blood vessel network to tell the pituitary what to secrete. Learning these pairs creates a logical chain that reinforces your memory of the hormones themselves.
The naming pattern is almost too simple. Corticotropin-releasing hormone (CRH) triggers ACTH. Thyrotropin-releasing hormone (TRH) triggers TSH. Gonadotropin-releasing hormone (GnRH) triggers both FSH and LH, which is why they’re grouped together as gonadotropins. Growth hormone-releasing hormone (GHRH) triggers growth hormone. In each case, the releasing hormone’s name mirrors the pituitary hormone it controls.
Prolactin is the odd one out. Instead of being switched on by a releasing hormone, prolactin is held in check by dopamine. The anterior pituitary will secrete prolactin continuously unless dopamine actively suppresses it. This is worth remembering on its own because it comes up constantly in pharmacology: any drug that blocks dopamine (certain antipsychotics, for example) can raise prolactin levels as a side effect.
Anterior vs. Posterior: Don’t Mix Them Up
A common exam trap is confusing anterior pituitary hormones with posterior ones. The distinction is straightforward once you know the embryology. The anterior pituitary (adenohypophysis) is glandular tissue that originally developed from the digestive tract and migrated toward the brain during fetal development. It manufactures its own hormones. The posterior pituitary (neurohypophysis) is neural tissue, essentially an extension of the hypothalamus. It does not make hormones at all. It only stores and releases two hormones that the hypothalamus produces: oxytocin and ADH (antidiuretic hormone, also called vasopressin).
A quick way to keep them straight: “adeno” means gland, so the adenohypophysis is the factory that builds hormones. “Neuro” means nerve, so the neurohypophysis is just a warehouse at the end of nerve fibers. If a hormone is on the FLAT PeG list, it’s made in the anterior pituitary. If it’s oxytocin or ADH, it’s stored in the posterior.
The Cell Types That Produce Each Hormone
If your course requires you to know which cell type makes which hormone, there are five to learn. Each is named for the hormone it produces, which keeps things predictable:
- Somatotropes produce growth hormone (soma = body)
- Lactotrophs produce prolactin (lacto = milk)
- Corticotropes produce ACTH (cortico = adrenal cortex)
- Thyrotropes produce TSH (thyro = thyroid)
- Gonadotropes produce FSH and LH (gonado = gonads)
Notice that gonadotropes handle two hormones, not one. That’s because FSH and LH work as a pair on the same target organs. Corticotropes also deserve a special note: ACTH is cleaved from a larger precursor molecule called POMC, and endorphins are a byproduct of that same process. That’s why endorphins sometimes appear on the anterior pituitary hormone list even though they don’t have their own dedicated cell type.
Putting It All Together
The most effective way to lock this into long-term memory is to build layers. Start with FLAT PeG to recall the raw list. Then mentally sort the hormones into tropic (ACTH, TSH, FSH, LH) versus direct (GH, prolactin). Next, trace each one back to its hypothalamic trigger: CRH to ACTH, TRH to TSH, GnRH to FSH and LH, GHRH to GH, and dopamine inhibiting prolactin. Finally, connect each hormone forward to its target: ACTH hits the adrenals, TSH hits the thyroid, FSH and LH hit the gonads, GH hits virtually every tissue, and prolactin hits breast tissue.
That gives you a complete chain from hypothalamus to anterior pituitary to target organ for every hormone. When you can walk through that chain from memory, you’re not just recalling a mnemonic. You understand the system, which means the details are far less likely to slip away under exam pressure.