75 TRANSIENT GROWTH HORMONE DEFICIENCY DURING BROMOCRYPTINE TREATMENT FOR HYPERPROLCATINEMIA

Abstract

Growth hormone (GH) deficiency has been demonstrated in several patients with prolactinoma. Very often it was attrituted to tumor expansion and found to be permanent after surgery. In a 14-year-old boy with galactorrhea, arrested puberty (testesvolume 4ml) and poor growth (3cm/year) elevated prolactin (PRL) levels (5800 mU/l) were found. MR imaging showed no abnormalities of the pituary gland. Nighttime sampling revealed persistent PRL elevation and low GH peaks (max. 12 mU/l). GH response to insuline induced hypoglycemia was also low (max. 10 mU/l) but GH increased normally after GRF injection (38 mU/l). Basal and stimulated LH and FSH values were prepubertal. 3 h. after the administration of 10 mg bromocryptine (B) PRL dropped to normal values and GH increased to 22 mU/l. After six months of treatment with B, height velocity doubled and normalization of GH secretion was observed. Basal LH, FSH and testosterone values remained prepubertal. In conclusion, GH deficiency in hyperprolactinemia can be restored during B treatment. The acute GH response to B may be predictive of the subsequent normalization of GH secretion during long term treatment. In Isolated hyperprolactinemia a central dopaminergie defect is probably responsible for this deficient GH secretion.