The anterior pituitary gland plays a central role in regulating endocrine function, growth, metabolism, stress response, reproductive health, and lactation. Hormones secreted from this “master gland” affect nearly every physiological system in the human body.
Medical and biology students often struggle to recall these hormones during exams and clinical rotations. That’s where the mnemonic FLAT PaGE becomes a powerful memory aid.
This article explores the FLAT PaGE mnemonic, detailing the functions, target organs, mechanisms, and clinical relevance of each hormone. Whether you’re studying for NEET PG, USMLE, or just brushing up on endocrine physiology, this guide provides clear, visual, and practical insights into anterior pituitary hormones.
What Is the FLAT PaGE Mnemonic?
"FLAT PaGE" stands for:
- F: Follicle Stimulating Hormone (FSH)
- L: Luteinizing Hormone (LH)
- A: Adrenocorticotropic Hormone (ACTH)
- T: Thyroid Stimulating Hormone (TSH)
- P: Prolactin
- G: Growth Hormone (GH)
- E: Endorphins
This mnemonic helps students and professionals remember all seven major hormones secreted by the anterior pituitary (adenohypophysis).
These hormones are divided into:
- Tropic hormones (FLAT) – stimulate other endocrine glands
- Direct hormones (PaGE) – act directly on target tissues
Follicle Stimulating Hormone (FSH)
Function:
FSH regulates:
- Development of ovarian follicles in females
- Spermatogenesis in males
Target Organs:
- Ovaries: stimulates granulosa cells
- Testes: stimulates Sertoli cells
Regulation:
- Stimulated by: Gonadotropin-releasing hormone (GnRH) from the hypothalamus
- Inhibited by: Inhibin (from testes/ovaries) and estrogen/testosterone via negative feedback
Clinical Relevance:
- Low FSH: infertility, delayed puberty
- High FSH: menopause, gonadal failure
Luteinizing Hormone (LH)
Function:
LH triggers:
- Ovulation and corpus luteum formation in females
- Testosterone production in males
Target Organs:
- Ovaries: acts on theca cells
- Testes: stimulates Leydig cells
Regulation:
- Stimulated by: GnRH pulses
- Inhibited by: Negative feedback from sex hormones
Clinical Relevance:
- LH surge = key marker of ovulation
- LH measurement aids fertility assessments
Adrenocorticotropic Hormone (ACTH)
Function:
ACTH stimulates the adrenal cortex to produce:
- Cortisol (main stress hormone)
- Minor amounts of aldosterone and androgens
Target Organ:
- Adrenal cortex, specifically the zona fasciculata
Regulation:
- Stimulated by: Corticotropin-releasing hormone (CRH)
- Inhibited by: Negative feedback from cortisol
Clinical Relevance:
- High ACTH: Cushing’s disease
- Low ACTH: Addison’s disease, pituitary insufficiency
Thyroid Stimulating Hormone (TSH)
Function:
TSH promotes:
- Synthesis and release of T3 and T4 (thyroid hormones)
Target Organ:
- Thyroid gland
Regulation:
- Stimulated by: Thyrotropin-releasing hormone (TRH)
- Inhibited by: T3 and T4 via negative feedback
Clinical Relevance:
- High TSH: hypothyroidism
- Low TSH: hyperthyroidism, pituitary dysfunction
Prolactin (PRL)
Function:
Prolactin is responsible for:
- Milk production in lactating women
- Modulation of immune system and behavior
Target Organ:
- Mammary glands
Regulation:
- Stimulated by: Suckling, estrogen, TRH
- Inhibited by: Dopamine (Prolactin Inhibiting Hormone)
Clinical Relevance:
- High PRL: galactorrhea, infertility
- Low PRL: rare, but may affect lactation
Growth Hormone (GH)
Function:
GH supports:
- Linear bone growth in children
- Muscle mass and fat metabolism in adults
Target Organs:
- Liver (produces IGF-1)
- Bones and muscles
Regulation:
- Stimulated by: GHRH, sleep, stress, hypoglycemia
- Inhibited by: Somatostatin, high glucose, IGF-1
Clinical Relevance:
- Excess GH: acromegaly/gigantism
- Deficiency: short stature in children
Endorphins
Function:
Endorphins act as:
- Natural painkillers
- Mood enhancers (euphoria)
Target Organs:
- Central Nervous System (CNS)
Regulation:
- Released during exercise, pain, laughter, and stress
Clinical Relevance:
- Basis for opioid mechanisms
- Low endorphins linked to depression
Hormone Classification: Tropic vs Direct
| Classification | Hormones | Description |
|---|---|---|
| Tropic | FSH, LH, ACTH, TSH | Stimulate other endocrine glands |
| Direct | Prolactin, GH, Endorphins | Act directly on target tissues |
Mnemonic recap:
- FLAT = Tropic
- PaGE = Direct
Clinical Disorders of Anterior Pituitary Hormones
| Hormone | Excess (Hyper) | Deficiency (Hypo) |
|---|---|---|
| FSH / LH | Rare, PCOS | Hypogonadism, infertility |
| ACTH | Cushing’s disease | Addison’s disease |
| TSH | Secondary hyperthyroidism | Central hypothyroidism |
| Prolactin | Prolactinoma | Poor lactation |
| GH | Acromegaly / Gigantism | Growth retardation, adult GH def. |
| Endorphins | Unclear | Linked to chronic pain, depression |
Frequently Asked Questions (FAQ)
Q1. What is the function of the anterior pituitary gland?
It secretes hormones that regulate growth, metabolism, reproduction, lactation, and stress response.
Q2. What does the mnemonic FLAT PaGE stand for?
FSH, LH, ACTH, TSH, Prolactin, GH, and Endorphins — the major anterior pituitary hormones.
Q3. Which hormones are tropic and which are direct?
Tropic: FSH, LH, ACTH, TSH.
Direct: Prolactin, GH, Endorphins.
Q4. What stimulates the release of anterior pituitary hormones?
Hypothalamic releasing hormones like GnRH, TRH, CRH, and GHRH.
Q5. How is the anterior pituitary connected to the hypothalamus?
Via the hypophyseal portal system — a vascular link that allows hormonal control.
