Prolactin response to growth hormone stimulation tests

Background: Despite many similarities between the structure, receptors, proliferative and growth promoting actions, the relationship between Prolactin (PRL) and Growth Hormone (GH) in clinical conditions has received little attention. Objective: To determine the PRL response to GH stimulation tests. Subjects: Prepubertal and early pubertal boys (n = 581) and girls (n = 502) with idiopathic, non-syndromatic short stature. Design: Data was retrieved from the computerized records of the Endocrine Laboratory, Schneider Children's Medical Center. Peak GH and PRL levels during GH stimulation tests with glucagon (Gluc), Clonidine (Clon) and Clonidine with arginine (Clon+Arg), were compared. Both PRL and GH were determined by radioimmunoassay. Results: Whereas Gluc stimulated both GH and PRL to similar levels, Clon alone or combined with Arg suppressed the PRL secretion (p < 0.0001). It is also evident that in both boys and girls Clon alone and Clon??Arg are superior to Gluc in GH stimulation. The higher GH levels during Clon+Arg than with Clon alone are attributed to the pubertal stage. Conclusion: This study provides further information on the Prolactin-Growth hormone relationship in children.