Topic overview

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Hypothalamic releasing and inhibiting peptides reach the anterior pituitary through portal vessels, while hypothalamic neuropeptides are transported to the posterior pituitary for storage and release. Secretion is shaped by timing: pulsatile GnRH supports responsiveness, whereas continuous exposure can suppress downstream release through receptor desensitization. Peripheral hormones provide long-loop negative feedback at both hypothalamic and pituitary levels. The lesson distinguishes anterior pituitary hormones—including GH, prolactin, ACTH, TSH, LH, and FSH—by their regulation and actions, then introduces vasopressin and oxytocin. Key examples connect receptor signaling to effects such as water reabsorption, vasoconstriction, thyroid hormone secretion, and uterine or mammary activity.