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Billy Step 1 Questions # 84

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endocrine-
2K views 8 replies 8 participants last post by  koolkiller88 
#1 ·
An endocrine research laboratory is investigating the regulation of the hypothalamic-pituitary axis both through pharmacologic means and by direct ablation of different regions of the brains of chimpanzees. They find that extremely high doses of chlorpromazine as well as destruction of the hypothalamus causes the levels of a certain hormone to rise. Levels of what hormone were found to be elevated?


(A) ADH
(B) Growth hormone
(C) Luteinizing hormone
(D) Oxytocin
(E) Prolactin
(F) Testosterone
(G) Thyroid-releasing hormone
 
#8 ·
E is correct

The hypothalamus regulates prolactin release by the anterior pituitary.
Thyroid-releasing hormone stimulates prolactin release, while dopamine inhibits it. Prolactin stimulates milk production and breast development while inhibiting ovulation and spermatogenesis. Destruction of the hypothalamus would cause a reduction in dopamine secretion, increasing prolactin release. The antipsychotic chlorpromazine is a dopamine receptor antagonist, and would therefore also cause an increase in prolactin release.
 
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