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The pituitary gland earns its nickname as the "master gland" because it orchestrates hormone release throughout your entire body—but here's what you're really being tested on: the feedback loops and target organ relationships that keep these systems in balance. Understanding pituitary hormones means understanding how the hypothalamus communicates with peripheral glands, how negative feedback maintains homeostasis, and what happens when these systems fail. You'll see these concepts appear in questions about endocrine pathology, reproductive physiology, fluid balance, and stress responses.
Don't just memorize which hormone does what—know which lobe secretes it, what releases or inhibits it, and what target tissue responds. The pituitary is divided into the anterior lobe (adenohypophysis) and posterior lobe (neurohypophysis), and this distinction matters for understanding both hormone synthesis and clinical disorders. Master these relationships, and you'll be ready for everything from multiple choice to complex case-study questions.
Tropic hormones act on other endocrine glands to stimulate hormone release—they're the messengers that carry hypothalamic commands to peripheral targets.
Compare: FSH vs. LH—both are gonadotropins released by GnRH, but FSH supports gamete development while LH triggers hormone production and ovulation. If an FRQ asks about infertility, discuss how both must function together for reproduction.
These hormones act directly on non-endocrine target tissues rather than stimulating other glands—they complete their effects without an intermediary.
Compare: GH vs. Prolactin—both are direct-acting anterior pituitary hormones, but GH works through an intermediary (IGF-1) while prolactin acts directly on breast tissue. Both are released during sleep and stress.
This hormone bridges the endocrine and integumentary systems, demonstrating how pituitary signals extend beyond traditional metabolic targets.
Compare: MSH vs. ACTH—both derive from the POMC precursor, which explains why adrenal insufficiency causes skin darkening. This shared origin is a favorite exam topic for connecting endocrine pathways.
The posterior pituitary doesn't synthesize hormones—it stores and releases hormones made by hypothalamic neurons. These are true neurohormones transported down axons to the posterior lobe.
Compare: ADH vs. Oxytocin—both are nonapeptides synthesized in hypothalamic nuclei and released from the posterior pituitary, but ADH regulates fluid balance while oxytocin controls reproductive smooth muscle. Both demonstrate how the nervous and endocrine systems integrate.
| Concept | Best Examples |
|---|---|
| Tropic hormones (act on other glands) | ACTH, TSH, FSH, LH |
| Direct-acting hormones | GH, Prolactin, MSH |
| Posterior pituitary release | ADH, Oxytocin |
| Gonadotropins | FSH, LH |
| Negative feedback regulation | TSH/thyroid hormones, ACTH/cortisol, GH/IGF-1 |
| Positive feedback examples | LH surge, Oxytocin during labor |
| POMC-derived hormones | ACTH, MSH |
| Hypothalamic inhibition | Prolactin (by dopamine), GH (by somatostatin) |
Which two anterior pituitary hormones share a common precursor molecule, and how does this explain hyperpigmentation in Addison's disease?
Compare and contrast FSH and LH: What target cells does each act on in males, and how do their functions differ?
A patient presents with dilute urine and excessive thirst despite adequate fluid intake. Which pituitary hormone is likely deficient, and what receptor mechanism is impaired?
Why does continuous GnRH administration suppress gonadotropin release, even though pulsatile GnRH stimulates it? How is this principle used clinically?
If an FRQ asks you to explain why a prolactin-secreting pituitary tumor causes both galactorrhea and infertility, what two mechanisms would you describe?