title: Age-related alterations in the stimulated release in vitro of catecholamines and luteinizing hormone-releasing hormone from the male rat hypothalamus.
abstract: Using an in vitro perifusion system, the present study investigated the possibility that alterations in catecholamine and luteinizing hormone-releasing hormone (LHRH) secretion from the male rat mediobasal hypothalamus are present during the period of middle-age. The results indicate that, while tissue concentrations and baseline secretion of norepinephrine, dopamine and LHRH were similar between age groups, the patterns of dopamine and LHRH release in response to a series of depolarizing stimuli was different in the older animals. After all challenges, dopamine concentrations in the perifusate declined much more sharply for the middle-aged group, a finding that may be associated with a decrease with age in the pool of transmitter available for ready release. Also, tissue fragments from young adult rats were able to maintain the release of LHRH to a greater extent than tissue from the middle-aged animals, but only for the initial challenge period. The typical episodic pattern of LHRH release appeared to be disrupted in the older group following a second stimulus. It is possible that these age-related changes are early components of a disruption in the hypothalamic mechanisms governing gonadotropin secretion.
authors.forename: J M
authors.initials: JM
authors.lastname: Goldman
authors.forename: R L
authors.initials: RL
authors.lastname: Cooper
authors.forename: G L
authors.initials: GL
authors.lastname: Rehnberg
authors.forename: S
authors.initials: S
authors.lastname: Gabel
authors.forename: W K
authors.initials: WK
authors.lastname: McElroy
authors.forename: J
authors.initials: J
authors.lastname: Hein
authors.forename: P M
authors.initials: PM
authors.lastname: Conn
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D046508:Culture Techniques; D004298:Dopamine / Q000378:metabolism; D004558:Electric Stimulation; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007033:Hypothalamus, Middle / Q000502:physiology*; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002395:Catecholamines; D007987:Gonadotropin-Releasing Hormone; D004298:Dopamine; D009638:Norepinephrine