Reduced serum cholecystokinin and increase in body fat during oral contraception

This investigation was undertaken to explore a possible role of the "satiety peptide" cholecystokinin and some other gastrointestinal hormones for changes in appetite and weight during oral contraception. Ten young healthy women attending a youth health care center for contraceptive counseling volunteered for the study. A standardized meal test was used for recordings of appetite and gastrointestinal hormone response before and after 5 months of treatment with a monophasic combined oral contraceptive. Body fat was calculated from measurements of skin-fold thickness. Oral contraceptives caused a suppression of basal levels of serum cholecystokinin, which was correlated to an increase in body fat. Meal-related response of cholecystokinin and appetite were not affected. Serum levels of gastrin and insulin were also unchanged, whereas triglycerides and postprandial glucose levels were elevated. The results suggest a role of cholecystokinin in regulation of body composition. Cholecystokinin stimulates the release of insulin and stimulates lipolysis in adipose tissue. Reduced cholecystokinin levels may, therefore, be related to mild impairment of glucose tolerance and promote body fat storage during oral contraception.