Age-associated reduction of stimulatory effect of ghrelin on food intake in mice.

Aging is associated with a progressive decrease in appetite and food intake. We focused on the age-associated changes of the stimulatory effect of the appetite-regulating peptide, ghrelin. Food intake and the concentrations of acyl ghrelin and desacyl ghrelin in the plasma and in the stomach were measured with and without overnight fasting in young and old mice.

Age-associated changes of appetite-regulating peptides.

Aging is associated with a progressive decrease in appetite and food intake. The reasons for the decline in food intake are multifactorial, and relate to both peripheral and central mechanisms. Current studies about the regulation of food intake suggest that there are many central mediators that control the appetite.

Gastric acid secretion in cholecystokinin-1 receptor, -2 receptor, and -1, -2 receptor gene knockout mice.

Gastrin is important for stimulating acid secretion as well as differentiating gastric mucosal cells via cholecystokinin-2 receptors (CCK-2Rs). In turn, CCK acts preferably via CCK-1R to release somatostatin, and somatostatin has been postulated to exhibit a tonic inhibition of gastrin bioactivity. The present study was designed to examine the hypothesis that CCK-1R and 2R may act in opposite directions in gastric acid secretion.

Age-associated gallstone formation in male and female CCK-1(A) receptor-deficient mice.

Background: Gallbladder dysmotility accelerates cholelithiasis. In turn, gallbladder dysmotility can occur secondary to inflammation and excess cholesterol accumulation in gallbladder smooth muscle.

Methods: The present study was designed to determine how much gallbladder dysmotility contributes to gallstone formation as a primary cause and whether a sex difference exists in gallstone formation by comparing cholecystokinin-1 receptor gene-deficient [CCK-1R(-/-)] male and female mice.

Susceptibility to obesity and gallbladder stasis produced by a protein- and fat-enriched diet in male mice compared with female mice.

Background: The frequency of Japanese subjects over 20 years old with metabolic syndrome is 45.6% in men but just 16.7% in women.