Publication

Intranasal insulin reduces body fat in men but not in women

Journal Paper/Review - Nov 1, 2004

Units
PubMed

Citation
Hallschmid M, Benedict C, Schultes B, Fehm H, Born J, Kern W. Intranasal insulin reduces body fat in men but not in women. Diabetes 2004; 53:3024-9.
Type
Journal Paper/Review (English)
Journal
Diabetes 2004; 53
Publication Date
Nov 1, 2004
Issn Print
0012-1797
Pages
3024-9
Brief description/objective

Insulin acts in the central nervous system to reduce food intake and body weight and is considered a major adiposity signal. After intranasal administration, insulin enters the cerebrospinal fluid compartment and alters brain functions in the absence of substantial absorption into the blood stream. Here we report the effects of 8 weeks of intranasal administration of insulin (4 x 40 IU/day) or placebo to two groups of healthy human subjects (12 men and 8 women in each group). The insulin-treated men lost 1.28 kg body wt and 1.38 kg of body fat, and their waist circumference decreased by 1.63 cm. Plasma leptin levels dropped by an average of 27%. In contrast, the insulin-treated women did not lose body fat and gained 1.04 kg body wt due to a rise in extracellular water. Our results provide a strong, first confirmation in humans that insulin acts as a negative feedback signal in the regulation of adiposity and point to a differential sensitivity to the catabolic effects of insulin based on sex.