Developmental expression of the genes encoding transforming growth factor alpha and its receptor in the hypothalamus of female rhesus macaques

Y. J. Ma, M. E. Costa, Sergio Ojeda

    Research output: Contribution to journalArticle

    95 Citations (Scopus)

    Abstract

    Studies in female rats have shown that transforming growth factor alpha (TGFα) stimulates release of luteinizing hormone-releasing hormone (LHRH), the neuropeptide controlling sexual maturation. and that expression of the TGFα gene in the hypothalamus increases during both the initiation of normal puberty and after hypothalamic lesions that induce sexual precocity. Since blockade of epidermal growth factor receptors (EGFR), which mediate TGFα actions, delayed the normal timing of puberty, it was postulated that TGFα/EGFR contributes to the neuroendocrine process that underlies the initiation of normal female puberty. The present study was undertaken to examine the hypothesis that hypothalamic expression of the TGFα gene and its receptor changes in relation to the stage of sexual development in nonhuman primates, and to determine whether these changes arc accompanied by corresponding alterations in LHRH gene expression. DNA fragments complementary to the coding regions of the rhesus monkey TGFα, EGFR and LHRH genes were cloned by reverse transcription-polymerase chain reaction (RT-PCR), sequenced and used to prepare monkey-specific antisense RNA probes. A quantitative RT-PCR was developed in which the cloned sequences were utilized to prepare RNA standards for the quantitation of tissue mRNA levels. Both TGFα and EGFR mRNA levels in the medial basal hypothalamus and preoptic area of female monkeys were elevated during neonatal life (1 week to 6 months of age), when FSH secretion is also high, decreased during juvenile development (8-18 months of age) when secretion of both FSH and LH is low, and markedly increased during the expected time of puberty (30-36 months of age). No such changes were observed in either the cerebellum or the cerebral cortex, two brain regions irrelevant to neuroendocrine reproductive control. In contrast to the pronounced alterations in hypothalamic TGFα/EGFR gene expression observed during sexual development, LHRH mRNA levels did not vary significantly during this time. Hybridization histochemistry revealed the presence of both TGFα and EGFR mRNAs in cells scattered throughout the hypothalamus, but more predominantly in the median eminence, suprachiasmatic nuclei, optic chiasm and cells along the wall of the third ventricle. These results demonstrate that increases in TGFα and EGFR gene expression, specific to the neuroendocrine brain, occur during developmental phases in which gonadotropin output is also elevated - most noticeably at the time of puberty. The remarkable parallelism between these changes and those in gonadotropin secretion known to occur during postnatal sexual development in primates, and the lack of developmental alterations in LHRH mRNA levels suggest that, as postulated in rodents, an activation of the TGFα ligand-EGF receptor system leading to LHRH gene-independent changes in LHRH release contributes to the the neuroendocrine control of female puberty in primates.

    Original languageEnglish (US)
    Pages (from-to)346-359
    Number of pages14
    JournalNeuroendocrinology
    Volume60
    Issue number4
    StatePublished - 1994

    Fingerprint

    Developmental Genes
    Transforming Growth Factor alpha
    Macaca mulatta
    Epidermal Growth Factor Receptor
    Hypothalamus
    Gonadotropin-Releasing Hormone
    Puberty
    Sexual Development
    Messenger RNA
    Primates
    erbB-1 Genes
    Gonadotropins
    Gene Expression
    Genes
    Reverse Transcription
    Haplorhini
    Middle Hypothalamus
    RNA Probes
    Optic Chiasm
    Antisense RNA

    Keywords

    • Female sexual development
    • Gene expression
    • Growth factor receptors
    • Hypothalamic growth factors
    • Messenger RNA
    • Primate puberty
    • Receptors
    • Transforming growth factor

    ASJC Scopus subject areas

    • Endocrinology
    • Neuroscience(all)

    Cite this

    Developmental expression of the genes encoding transforming growth factor alpha and its receptor in the hypothalamus of female rhesus macaques. / Ma, Y. J.; Costa, M. E.; Ojeda, Sergio.

    In: Neuroendocrinology, Vol. 60, No. 4, 1994, p. 346-359.

    Research output: Contribution to journalArticle

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