Influence of N-methyl-D-aspartate on the reproductive axis of male Syrian hamsters

Henryk Urbanski, M. M. Fahy, P. M. Collins

    Research output: Contribution to journalArticle

    11 Citations (Scopus)

    Abstract

    The influence of excitatory amino acids (EAAs) on reproductive neuroendocrine function was investigated in adult male Syrian hamsters of the LSH/Ss Lak strain. Before the study, the animals were maintained in a sexually regressed condition, under short days (SD) and subsequently were either transferred to long days (LD) or kept under SD, for a further 4 weeks. In the former group, photostimulation produced a predictable elevation in the hypophysial contents and serum concentrations of FSH and LH. This was accompanied by an increase in testicular size, an elevation in serum testosterone levels and an increase in spermatogenic activity; the SD hamsters remained sexually quiescent throughout the study. In contrast, SD hamsters that were given daily injections of the EAA agonist, N-methyl-D,L-aspartate (NMA; 50 mg/kg body weight, s.c.), showed stimulatory responses that were generally even more pronounced than those shown by the LD group. Surprisingly, an identical NMA treatment paradigm failed to cause a similar activation of the reproductive axis in LD hamsters that were given daily afternoon injections of melatonin (25 μg, s.c.), even though the inhibitory effect of this melatonin treatment is generally regarded as being comparable with that produced by exposure to SD. Although EAAs can acutely stimulate the neurocircuitry that controls LH-releasing hormone secretion, the present findings suggest that EAAs might also exert a long-term stimulatory action by acting further upstream in the photoneuroendocrine pathway.

    Original languageEnglish (US)
    Pages (from-to)247-252
    Number of pages6
    JournalJournal of Endocrinology
    Volume137
    Issue number2
    StatePublished - 1993

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    Excitatory Amino Acids
    Mesocricetus
    N-Methylaspartate
    Cricetinae
    Melatonin
    Excitatory Amino Acid Agonists
    Injections
    Serum
    Aspartic Acid
    Gonadotropin-Releasing Hormone
    Testosterone
    Body Weight
    Therapeutics

    ASJC Scopus subject areas

    • Endocrinology

    Cite this

    Influence of N-methyl-D-aspartate on the reproductive axis of male Syrian hamsters. / Urbanski, Henryk; Fahy, M. M.; Collins, P. M.

    In: Journal of Endocrinology, Vol. 137, No. 2, 1993, p. 247-252.

    Research output: Contribution to journalArticle

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