Abstract
In several species, IV or SC administration of NMA, a neuroexcitatory analog of aspartate, elicits a pulse of LH secretion. In prepubertal monkeys, chronic intermittent administration of NMA induces pubertal development through a putative hypothalamic action (Plant TM et al, Endocrine Soc, Meeting, 1987, Abst. 65). In order to get a direct insight into this mechanism, GnRH releast from the rat hypothalamus was studied in vitro in the presence of NMA. Concentrations ≤ 0.74 mg/ml were not effective. Incubation with NMA 1.47 mg/ml for 7.5 min resulted in an increase of GnRH release from 11.5 ± 4.3 to 36.2 ± 14.1 pg/0.5 ml (mean ± SD, n= 12). The effect of NMA in vivo was evaluated by studying rats sacrificed at different times after SC injection of 30 mg/kg of NMA. One, 3, 5, 7.5 and 10 min after NMA injection, mean serum LH rose progressively (32.0, 38.0, 70.0, 71.0 and 87.5 ng/ml, respectively). The hypothalami of these rats were immediately dissected and studied in vitro. One, 3, 5, 7.5 and 10 min after NMA injectior in vivo, mean GnRH release in vitro showed a marked increase (20.0, 32.0, 46.3, 115.5 and 41.8 pg/0.5 ml, respectively), indicating that CnRH is likely the neuroendocrine mediator of NMA-induced LH secretion. The study of GnRH release by NMA in vitro provides a means to further elucidate the mechanisms of the hypothalamic pulse generator and its role in the initiation of puberty.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bourguignon, J., Gerard, A., Charlet-Renard, C. et al. 130 STIMULATION OF GnRH SECRETON BY N-METHYL-D, L-ASPARTATE (NMA) IN VITRO AND IN VIVO. Pediatr Res 24, 538 (1988). https://doi.org/10.1203/00006450-198810000-00151
Issue Date:
DOI: https://doi.org/10.1203/00006450-198810000-00151