Study of the Effect of Growth Hormone-Releasing Hormone Antagonist on Growth Hormone Release in Acromegaly
Study of the Effect of Growth Hormone-Releasing Hormone Antagonist on Growth Hormone Release in Acromegaly
OBJECTIVES: I. Determine whether release of endogenous growth hormone (GH)-releasing hormone
 is involved in GH responses to clonidine, pyridostigmine, levodopa, arginine, GH-releasing
 peptide, insulin-induced hypoglycemia, and exercise in patients with acromegaly.

 II. Determine whether endogenous GH-releasing hormone influences the maintenance of GH
 hypersecretion.
PROTOCOL OUTLINE: Growth hormone-releasing hormone antagonist (GHRH-A) is administered to
 volunteers and followed with 1 of these challenges: insulin, clonidine, pyridostigmine,
 arginine, levodopa, growth hormone-releasing peptide, or exercise. Tests are repeated with
 normal saline as the control; the order of administration (control vs. pharmacologic
 stimulation) is randomly assigned.

 Patients receive GHRH-A (dose determined in volunteer study), thyrotropin-releasing hormone,
 and growth-releasing hormone.

 All stimulation tests follow an overnight fast.
PROTOCOL ENTRY CRITERIA:

 --Disease Characteristics-- Active acromegaly with growth hormone (GH) hypersecretion
 confirmed within 1 month prior to entry, i.e.: Somatomedin C elevated GH not below 2 ng/mL
 on standard 100 g oral glucose tolerance test Postmenopausal and hypogonadal women eligible
 Volunteers aged 18 to 30 recruited for up to 3 stimulation tests Weight within 15% of ideal
 Physical exam normal No history of disease No requirement for medication No medical or
 mental contraindication to protocol participation, including heavy alcohol or tobacco use
 No pregnant women --Prior/Concurrent Therapy-- Not specified --Patient Characteristics--
 Age: 18 to 65 Hematopoietic: No anemia Hepatic: No hepatic disease Renal: No renal disease
 Cardiovascular: No uncontrolled hypertension No heart disease Other: No requirement for
 replacement gonadal steroids, glucocorticoids, or thyroxine No mental illness No heavy
 alcohol use No tobacco use No drug abuse No medical contraindication to protocol therapy