Leptin responses to antecedent exercise and hypoglycemia in healthy and type 1 diabetes mellitus men and women.
These studies examined the effects of hypoglycemia or exercise on leptin levels in 47 (23 women, 24 men) healthy (age 26+/-2 years, body mass index 23+/-0.5 kg.m(-2)) and type 1 diabetes mellitus (T1DM) subjects (age 29+/-2 years, body mass index 27+/-2 kg.m(-2)). In Study 1, healthy and T1DM subjects were exposed to morning and afternoon 120-min hyperinsulinemic hypoglycemic ( approximately 50 mg/dl) or euglycemic ( approximately 90 mg/dl) clamps. In Study 2, healthy subjects were studied during morning and afternoon 90-min exercise bouts at 50% VO(2max). In Study 1, basal levels of leptin were significantly greater in T1DM vs. the healthy subjects (13.8+/-3 vs. 5.4+/-1 ng/dl; P<.05). However, during the last 30 min of morning hypoglycemia, plasma leptin levels significantly decreased from 5.4+/-1 to 4.0+/-1 ng/dl (P<.05) and remained low during afternoon hypoglycemia (4.3+/-1 ng/dl) in healthy but not T1DM subjects. In Study 2, plasma leptin levels did not significantly change during exercise the bout in healthy men, but significantly decreased 3 h after morning exercise, and continued to decrease during afternoon exercise in healthy women (P<.0001). Thus, plasma leptin levels decrease in response to hypoglycemia in healthy but not T1DM subjects. However, T1DM patients do have increased basal leptin levels compared to healthy man. Lastly, there is a marked sexual dimorphism in plasma leptin responses to repeated episodes of exercise.
Department of Medicine, Vanderbilt University School of Medicine and Nashville Veterans Affairs Medical Center, Nashville, TN 37232, USA. darleen.sandoval@mcmail.vanderbilt.edu
Darleen A
DA
Sandoval
Pietro
P
Galassetti
Donna
D
Tate
Anthony
A
Neill
Stephen N
SN
Davis
D000222:Adaptation, Physiological; D000328:Adult; D016022:Case-Control Studies; D002940:Circadian Rhythm / Q000502:physiology; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D015309:Glucose Clamp Technique; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000503:physiopathology*; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood*; D008297:Male; D012016:Reference Values; D013312:Stress, Physiological / Q000097:blood* / Q000503:physiopathology
D007328:Insulin; D020738:Leptin