Failure to respond to growth hormone releasing hormone (GHRH) in acromegaly due to a GHRH secreting pancreatic tumor: dynamics of multiple endocrine testing.
Growth hormone releasing hormone (GHRH) has recently been isolated and sequenced from pancreatic tumors secreting GHRH. Patients with untreated acromegaly due to a pituitary tumor respond to exogenous administration of GHRH with a further rise of their elevated basal growth hormone (GH) levels. For the first time, we report the effects of exogenously administered synthetic GHRH in a patient with acromegaly due to a GHRH secreting pancreatic tumor. The diagnosis was established by high peripheral IR-GHRH levels (1100 pg/ml) and an arterio- venous tumor gradient of IR-GHRH. In this patient GH failed to respond to 1 microgram/kg of exogenous GHRH with the pancreatic tumor in situ; however, further increase of serum GH levels occurred after TRH administration, hypoglycemia and oral glucose administration. After removal of the tumor, serum GH levels decreased and a normal response to GHRH and TRH were demonstrated. The extract of the tumor contained 1.7 micrograms IR-GHRH per g wet tissue. Thus, lack of response to exogenous GHRH in untreated acromegaly may indicate the presence of an ectopic GHRH producing tumor.
D000172:Acromegaly / Q000097:blood* / Q000209:etiology; D005260:Female; D013006:Growth Hormone / Q000097:blood; D013007:Growth Hormone-Releasing Hormone / Q000378:metabolism*; D006801:Humans; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D011388:Prolactin / Q000097:blood
D011388:Prolactin; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone