N-methyl D,L-aspartate induces the release of luteinizing hormone-releasing hormone in the prepubertal and pubertal female rhesus monkey as measured by in vivo push-pull perfusion in the stalk-median eminence
Le. Claypool et al., N-methyl D,L-aspartate induces the release of luteinizing hormone-releasing hormone in the prepubertal and pubertal female rhesus monkey as measured by in vivo push-pull perfusion in the stalk-median eminence, ENDOCRINOL, 141(1), 2000, pp. 219-228
The role of the excitatory amino acid glutamate, N-methyl D-aspartate (NMDA
) receptor agonist, in stimulating in vivo luteinizing hormone-releasing ho
rmone (LHRH) release in the stalk-median eminence of conscious prepubertal
and pubertal female rhesus monkeys was evaluated using push-pull perfusion.
In Exp 1, the effects of iv bolus injection of N-methyl D,L-aspartate (NMA
) on LHRH release were examined. Injection of NMA induced an increase in LH
RH release in all maturational stages of monkeys. Although the LHRH respons
e to NMA tended to be larger in the older groups, only the duration of the
LHRH response in the midpubertal group was significantly longer than that i
n the prepubertal group. In Exp 2, the effects of direct infusion of NMA (0
.1, 1, and 100 mu M) into the stalk-median eminence on LHRH release were si
milarly examined. NMA infusion stimulated LHRH release in pubertal monkeys,
whereas it did not induce any consistent changes in LHRH release in prepub
ertal monkeys except for the highest dose. These data suggest that: 1) the
systemic injection of NMA is more effective than direct infusion of NMA; an
d 2) the prepubertal LHRH neurosecretory system is capable of responding to
NMDA, although the responsiveness may undergo developmental changes. There
fore, stimulation of NMDA receptors may contribute to the pubertal changes
in the LHRH neurosecretory activity.