title: Age-related changes in the oestrous cycle and reproductive hormones in senescence-accelerated mouse.
abstract: To investigate age-related changes in the oestrous cycle and reproductive hormone levels in senescence-accelerated mouse (SAM), we examined these parameters in 3-, 5-, 7-, 9- and 11-month-old female SAM-prone/8 (SAMP8) and SAM-resistant/1 (SAMR1) strains. Levels of beta-endorphin (beta-EP) and substance P (SP) in the hypothalamus were also measured. The oestrous cycle and dioestrus of 9-month-old SAMP8 mice were significantly prolonged compared with age-matched SAMR1 mice. Furthermore, the concentration of serum oestradiol was lower and the level of pituitary luteinising hormone was higher in SAMP8 mice compared with SAMR1 mice. This characterises the hypothalamus-pituitary-ovary (HPO) axis of the SAMP8 strain as hypergonadotropic-hypogonad. The levels of beta-EP and SP in the SAMP8 hypothalamus were lower than in the SAMR1 hypothalamus. These results indicate that the function of the HPO axis in SAMP8 mice declines early and this may be attributed, in part, to the decline in beta-EP and SP concentrations in the hypothalamus.
authors.affiliation: Department of Neuro-Immuno Pharmacology of Traditional Chinese Medicine, Beijing Institute of Pharmacology and Toxicology, China.
authors.forename: Ma
authors.initials: M
authors.lastname: Yuan
authors.forename: Zhou
authors.initials: Z
authors.lastname: Wen-Xia
authors.forename: Cheng
authors.initials: C
authors.lastname: Jun-Ping
authors.forename: Zhang
authors.initials: Z
authors.lastname: Yong-Xiang
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D004031:Diestrus; D004958:Estradiol / Q000097:blood*; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D007031:Hypothalamus / Q000737:chemistry; D007986:Luteinizing Hormone / Q000032:analysis*; D008297:Male; D051379:Mice; D008806:Mice, Inbred AKR; D010902:Pituitary Gland / Q000737:chemistry*; D012098:Reproduction / Q000502:physiology*; D013373:Substance P / Q000032:analysis; D001615:beta-Endorphin / Q000032:analysis
chemical_list: D013373:Substance P; D004958:Estradiol; D001615:beta-Endorphin; D007986:Luteinizing Hormone