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1. 1
PROLACTIN PRODUCING ADENOMA
Most common pituitary tumor
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2. Prolactin
 Synthesized in lactotropes
 20% of anterior pituitary cells
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3. Common precursor cell
 For lactotropes and somatotropes
 May give rise to a tumor secreting both
prolactin and growth hormone
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4. When does prolactin synthesis
begin?
 Fetus
 12 weeks gestation
 4 weeks after GH
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5. Prolactin secretion
 Pulsatile
 Peak serum prolactin levels
 Between 4:00 and 6:00 A.M
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6. Circulating half-life of prolactin
 50 minutes
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7. Dopamine
 Prolactin inhibitory factor
 Suppresses prolactin release
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9. Pituitary stalk section
 Mass lesions at the skull base
 Prolactin hypersecretion
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10. Primary action of prolactin
 Induce and maintain lactation
 Clinical problems
 Effect of prolactin on gonadal function
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11. Hyperprolactinemia
 Anovulation
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12. Hypersecretion of prolactin
 Infertility
 Gonadal dysfunction
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13. Prolactin
 Suppresses hypothalamic GnRH
 Inhibit the release of LH and FSH
 Impair gonadal steroidogenesis
 Hypoestrogenism and anovulation
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14. Prolactin
 Ensure that maternal lactation is sustained
 Not interrupted by pregnancy
 Decreases reproductive function
 Suppress sexual drive
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15. Increase calcium absorption
 Gastrointestinal calcium absorption is
increased
 Bone calcium is mobilized
 Hyperprolactinemia
 Increases bone loss
 May cause osteoporosis
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16. Males
 Decreased spermatogenesis
 Reduced LH secretion
 Low testosterone levels
 Decreased spermatogenesis
 Decrease libido
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17. Which of the following is not a
prolactin action?
A. Induce and maintain lactation
B. Anovulation
C. Decreased spermatogenesis
D. Increase calcium absorption
E. Pubertal mammary development
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18. Answer
 Pubertal mammary development
 Prolactin is not essential
 Requires GH
 Action mediated by IGF-I
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19. What is the most common
pituitary hormone
hypersecretion syndrome in
males?
A. Acromegaly
B. Cushing’s disease
C. Hyperprolactinemia
D. Diabetes
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20. Answer
 Hyperprolactinemia
 Both males and females
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Endocrinology
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