A longitudinal hormonal profile of the genetically obese mouse.
Obese mice (C57BL/6J ob/ob) and their lean littermates were studied at various ages from immediately post weaning until 62 weeks of age, at which mortality increased markedly. Several age-related changes were noted. 1) Plasma glucose levels were elevated in obese mice 5-20 weeks and 62 weeks of age, but were similar to those in the lean mice at 20-60 weeks of age. Plasma insulin levels were elevated in obese mice, and there were no age-related differences. 2) Brain serotonin was elevated in obese mice at all ages and increased with age in both obese and lean animals. 3) Pituitary contents of ACTH and beta-endorphin were elevated in young obese mice and increased further as these mice approached their life expectancy. 4) The ratios of ACTH to beta-endorphin immunoreactivities were similar in obese and lean mice, except in obese mice over 50 weeks of age where this ratio was increased. We conclude that: 1) the obese mouse is characterized by hyperinsulinemia and hyperadrenocorticism throughout its life; 2) the insulin resistance of the obese mouse improves at 20 weeks of age, yet deteriorates as its life expectancy is approached; 3) the obese mouse has an elevated brain serotonin content similar to previously described elevations of the putative neurotransmitters dopamine and norepinephrine in these mice; and 4) as the obese mouse approaches its life expectancy, abnormalities may occur in the synthesis, processing, or secretion of ACTH and/or beta-endorphine.
D000324:Adrenocorticotropic Hormone / Q000032:analysis; D000375:Aging; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001921:Brain / Q000254:growth & development; D001923:Brain Chemistry; D003345:Corticosterone / Q000097:blood; D004723:Endorphins / Q000032:analysis; D007328:Insulin / Q000097:blood; D008297:Male; D051379:Mice; D008820:Mice, Obese / Q000254:growth & development*; D010902:Pituitary Gland / Q000032:analysis; D011506:Proteins / Q000032:analysis; D012701:Serotonin / Q000032:analysis; D013045:Species Specificity
D001786:Blood Glucose; D004723:Endorphins; D007328:Insulin; D011506:Proteins; D012701:Serotonin; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone