title: Aging-related changes in release of growth hormone and luteinizing hormone in female rhesus monkeys.
abstract: A decline in somatic function with aging in women is associated with a decrease in GH release and a loss of estrogen after menopause. As an initial step to establish a monkey model for the neuroendocrine mechanisms underlying somatopause and menopause, we have conducted three experiments in unrestrained aged (approximately 25.7-yr-old) and young (approximately 5.4-yr-old) female rhesus monkeys. GH release was pulsatile, and mean GH release and pulse amplitude were significantly lower in aged monkeys than in young monkeys. Injection of GHRH alone, GH-releasing peptide-2 alone, or the combination of both induced an increase in GH release in both age groups. The mean LH level, pulse amplitude, and baseline LH levels were significantly higher in aged animals than in young animals. Both estrogen and IGF-I levels were lower in aged than young monkeys. These results suggest that in female rhesus monkeys 1) there is a clear decline in circulating GH and IGF-I levels with aging; 2) GHRH and GH-releasing peptide-2 stimulate GH release synergistically; and 3) circulating LH levels increase as estrogen decreases with aging. These results indicate that the rhesus monkey is an excellent model for studies of the neuroendocrine mechanisms of aging.
authors.affiliation: Wisconsin Primate Research Center, 1223 Capitol Court, Madison, Wisconsin 53715, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Woller
authors.forename: Gina
authors.initials: G
authors.lastname: Everson-Binotto
authors.forename: Elana
authors.initials: E
authors.lastname: Nichols
authors.forename: Ashley
authors.initials: A
authors.lastname: Acheson
authors.forename: Kim L
authors.initials: KL
authors.lastname: Keen
authors.forename: Cyril Y
authors.initials: CY
authors.lastname: Bowers
authors.forename: Ei
authors.initials: E
authors.lastname: Terasawa
mesh_terms: D000375:Aging; D000818:Animals; D004347:Drug Interactions; D004958:Estradiol / Q000097:blood; D005260:Female; D013006:Growth Hormone / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000008:administration & dosage; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007986:Luteinizing Hormone / Q000378:metabolism*; D008253:Macaca mulatta / Q000254:growth & development* / Q000502:physiology; D009842:Oligopeptides / Q000008:administration & dosage; D010507:Periodicity; D011374:Progesterone / Q000097:blood
chemical_list: D009842:Oligopeptides; D011374:Progesterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D007986:Luteinizing Hormone; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; C091874:growth hormone-releasing peptide-2