SBA — Single Best Answer · Review
Question 498
Endocrinology → General
Classification
Question
SSBAQuestion Header
Growth hormone stimulates hepatic production of somatomedins. Which mechanism contributes to subsequent suppression of further growth hormone secretion?
Question Stem
Select the single best answer.
Options
A
Somatomedins stimulate hypothalamic somatostatin
B
Somatomedins stimulate pituitary gonadotrophin release
C
Somatomedins suppress hypothalamic dopamine
D
Somatomedins increase circulating glucose-independent growth hormone release
E
Somatomedins inhibit hypothalamic thyrotrophin-releasing hormone
Explanation
Growth hormone stimulates the liver to produce somatomedins, or insulin-like growth factors, which mediate effects on bone and cartilage. Somatomedins participate in negative feedback by stimulating hypothalamic somatostatin, thereby inhibiting further growth hormone secretion.
Option Validity
B) Pituitary gonadotrophins are not the feedback pathway described for somatomedin-mediated control of growth hormone.
C) Dopamine is particularly important in prolactin regulation, not the somatomedin feedback mechanism described here.
D) Somatomedins contribute to negative rather than positive feedback on growth hormone secretion.
E) Thyrotrophin-releasing hormone is not the mediator of this growth hormone feedback pathway.
Further Reading
Saxena, MRCOG-1 Basic Sciences, Endocrinology: Growth Hormone, pp. 304–305.