www.medicinemcq.com 1

PROLACTIN PRODUCING ADENOMA

Most common pituitary tumor

www.medicinemcq.com 2

Prolactin

Synthesized in lactotropes 20% of anterior pituitary cells

3

Common precursor cell

For lactotropes and somatotropes

May give rise to a tumor secreting both prolactin and growth hormone

www.medicinemcq.com

www.medicinemcq.com 4

When does prolactin synthesis begin?

Fetus 12 weeks gestation

4 weeks after GH

www.medicinemcq.com 5

Prolactin secretion

Pulsatile Peak serum prolactin levels

Between 4:00 and 6:00 A.M

6

Circulating half-life of prolactin

50 minutes

www.medicinemcq.com

www.medicinemcq.com 7

Dopamine

Prolactin inhibitory factor Suppresses prolactin release

www.medicinemcq.com 8

www.medicinemcq.com 9

Pituitary stalk section

Mass lesions at the skull base Prolactin hypersecretion

10

Primary action of prolactin Induce and maintain lactation Clinical problems

Effect of prolactin on gonadal function

www.medicinemcq.com

www.medicinemcq.com 11

Hyperprolactinemia

Anovulation

12

Hypersecretion of prolactin Infertility

Gonadal dysfunction

www.medicinemcq.com

www.medicinemcq.com 13

Prolactin

Suppresses hypothalamic GnRH Inhibit the release of LH and

FSHImpair gonadal steroidogenesis Hypoestrogenism and anovulation

www.medicinemcq.com 14

Prolactin

Ensure that maternal lactation is sustained

Not interrupted by pregnancy Decreases reproductive function Suppress sexual drive

www.medicinemcq.com 15

Increase calcium absorption Gastrointestinal calcium

absorption is increased Bone calcium is mobilized Hyperprolactinemia

Increases bone loss May cause osteoporosis

www.medicinemcq.com 16

Males

Decreased spermatogenesis Reduced LH secretion

Low testosterone levels Decreased spermatogenesis Decrease libido

www.medicinemcq.com

www.medicinemcq.com 17

Which of the following is not a prolactin action?

A. Induce and maintain lactation B. AnovulationC. Decreased spermatogenesis

D. Increase calcium absorption E. Pubertal mammary

development

www.medicinemcq.com 18

Answer

Pubertal mammary development Prolactin is not essential Requires GH

Action mediated by IGF-I

www.medicinemcq.com 19

What is the most common pituitary hormone hypersecretion syndrome in males?

A.AcromegalyB. Cushing’s diseaseC. HyperprolactinemiaD.Diabetes

www.medicinemcq.com 20

Answer

Hyperprolactinemia Both males and females

For rest of the slides, visit www.medicinemcq.com > Endocrinology