Age-related alterations in the stimulated release in vitro of catecholamines and luteinizing hormone-releasing hormone from the male rat hypothalamus.
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.
Goldman
J M
JM
Cooper
R L
RL
Rehnberg
G L
GL
Gabel
S
S
McElroy
W K
WK
Hein
J
J
Conn
P M
PM
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
D002395:Catecholamines; D007987:Gonadotropin-Releasing Hormone; D004298:Dopamine; D009638:Norepinephrine