Free Fatty Acids, Body Weight, and Growth Hormones Secretion in Children

• INCLUSION CRITERIA:

Subjects will qualify for the overweight group if they meet the following criteria:

1. Good general health.
2. Age greater than or equal to 7 and less than 15 years.
3. Tanner stage I, II or III for the breast among girls and testes less than or equal to 10 mL for boys based upon an examination by a trained physician or nurse practitioner.
4. Weight > 30 kg.
5. Fasting plasma glucose < 100 mg/dL, 2 hour post-dextrose glucose < 140 mg/dL, and HgbA1C less than or equal to 6.4%.
6. Females who are age 10 or greater must have a negative pregnancy test.
7. Body mass index greater than or eqaul to 95th percentile determined by Centers for Disease Control age and sex specific data (given that most pathology of obesity does not usually emerge until children cross the 95th percentile).
8. No evidence of growth failure as defined as height > 5th percentile.

Subjects will qualify for the non-overweight control group if they meet the following criteria:

1. Recommended by a pediatric endocrinologist to undergo GH stimulation testing to establish the diagnosis of GH-deficiency.
2. Good general health.
3. Age greater than or equal to 7 and less than or equal to 15 years.
4. Tanner stage I, II or III for the breast among girls and testes less than or equal to 10 mL for boys based upon an examination by a trained physician or nurse practitioner.
5. Weight > 30 kg.
6. Fasting plasma glucose < 100 mg/dL, 2 hour post-dextrose glucose < 140 mg/dL, and HgbA1C less than or equal to 6.4%.
7. Females who are age 10 or greater must have a negative pregnancy test.
8. Height < 5th percentile.
9. BMI between the 5th and 85th percentiles determined by Centers for Disease Control age and sex specific data.
10. Birth weight and length not consistent with small for gestational age (SGA) criteria or a history of intrauterine growth restriction (IUGR) based on recall history.

EXCLUSION CRITERIA:

Subjects will be excluded if they have any of the following:

1. Baseline creatinine greater than or equal to 1.0 mg/dl.
2. Significant cardiac or pulmonary disease likely to or resulting in hypoxia or decreased perfusion.
3. Hepatic disease with elevated liver function tests (ALT or AST)greater than or equal to 1.5 the upper limits of normal.
4. Pregnancy.
5. Evidence for impaired glucose tolerance or Type 2 diabetes, including fasting plasma glucose greater than or equal to 100 mg/dL, 2 hour post-dextrose glucose greater than or equal to 140 mg/dL, or HgbA1C > 6.4%.
6. Presence of other endocrinologic disorders leading to obesity (e.g. Cushing Syndrome).
7. Any disorder that is known to affect GH secretion (e.g. untreated hypothyroidism) or use of any medication known to affect GH levels (including glucocorticoids and GH itself).
8. Any other disorder that is known to affect stature including skeletal dysplasias.
9. Recent use (within two years) of anorexiant medications, stimulant medications, or other medications felt to impact growth.
10. Individuals who have, or whose parent or guardians have, current substance abuse or a psychiatric disorder or other condition that, in the opinion of the investigators, would impede competence or compliance or possibly hinder completion of the study.
11. Individuals receiving medical treatment other than diet for hypertension or dyslipidemia.
12. Individuals with evidence of precocious puberty as defined as palpable breast tissue noted in females before the age of 7, testicular size greater than or equal to 4cc in males before the age of 9, or bone age advancement more than 2 SD for chronologic age.
13. Individuals receiving androgen or estrogen hormone therapy.