The exclusion criteria will include for both groups age less than 1 or more than 17 y/o, evidence of anemia (hemoglobin less tan 12 mg/dl), the use of medications that can directly impact blood sugar (steroids, oral contraceptives etc), history or proof of chemical abuse, lack of supportive family environment, allergies to local anesthetics and elevated liver enzymes. The GHD children will have a head MRI, and children with evidence of tumors or space occupying lesions will be excluded. GHD subjects with adrenal insufficiency and or hypothyroidism. will not be considered for the study.