Reduction of cholecystokinin-8S-neurons in the paraventricular hypothalamic nucleus of neonatally overfed weanling rats.

Cholecystokinin (CCK) is suggested to be involved, e.g. in the central nervous modulation of food intake, possibly by acting within specific hypothalamic nuclei. Perinatal overnutrition predisposes to permanent obesity and hyperphagia, while underlying mechanisms are unclear. By reducing the litter size from the 3rd to 21st day of life, early overnutrition was induced in newborn rats. At weaning, clear overweight (P < 0.001), hyperglycaemia (P < 0.05), hyperinsulinaemia (P < 0.001), and insulin resistance (P < 0.001) occured. These early signs of obesity were associated with a significantly decreased number of CCK-positive neurons in the paraventricular hypothalamic nucleus (P < 0.002). In conclusion, due to neonatal overfeeding malformation of CCKergic neurons at the end of the critical hypothalamic differentiation period occurs. Long-term consequences on CCK-related neuroendocrine regulations could be suggested, including those affecting food intake and body weight gain.