OBJECTIVES: I. Determine the response in plasma norepinephrine concentration and plasma glycerol to the agonist (clonidine) and the antagonist (yohimbine) of the alpha-2 adrenergic receptor in 6 patients with regional lipoatrophy and in 6 controls.

II. Determine the full sequence of the alpha-2 adrenergic receptor structural gene in genomic DNA from peripheral blood leukocytes.

PROTOCOL OUTLINE: Antihypertensives are held, beginning 3 days before the first study day.

An oral challenge is administered as follows: clonidine on day 1, yohimbine on day 2. The order of administration is reversed in alternate subjects.

Timed measurements of norepinephrine, glycerol, and free fatty acids follow each challenge. Structural gene sequencing is evaluated for each participant.

PROTOCOL ENTRY CRITERIA:

--Disease Characteristics-- Clinical diagnosis of regional lipoatrophy Control subjects: Women aged 18 to 65 Weight 90% to 150% of ideal No significant acute or chronic illness --Patient Characteristics-- Negative pregnancy test required of fertile women