To explore the therapeutic effects of Ziyin Xiehuo Recipe (ZYXHR) for nourishing yin and lowering fire and Yishen Tianjing Recipe (YSTJR) for nourishing kidney and replenishing essence on regulating the gonadotrophic and somatotrophic functions of hypothalamic-pituitary axis, and to reveal the mechanisms of ZYXHR and YSTJR in modulating the course of pubertal development of children with precocious puberty.
The pubertal rats were fed with ZYXHR or YSTJR for 30 days, and the parameters of rats were monitored as the followings: The content of gonadotropin-releasing hormone（GnRH）, the frequency and amplitude of GnRH impulse releasing, the releasing amounts of aminoacid neurotransmitters, and neuropeptide Y (NPY) and β-endorphin (β-END) in the gonadotrophic area of the hypothalamus were detected with neurobiological methods (push-pull perfusion, homogenate, incubation of brain slices, and immunohistochemical staining). The levels of gene and protein expressions of GnRH, growth hormone releasing hormone (GHRH) and somatostatin (SS) in hypothalamus, and follicular stimulating hormone (FSH), luteinizing hormone (LH) and growth hormone (GH) in adenohypophysis as well as insulin-like growth factorⅠ (IGF-Ⅰ) in metaphysis were determined with real time reverse transcription-polymerase chain reaction (RT-PCR).
The ZYXHR could reduce the activity of GnRH neurons in hypothalamus through inhibiting the release of central exciting aminoacid neurotransmitters, whereas promoting the release of central inhibiting aminoacid neurotransmitters, NPY and β-END in gonadotrophic area of hypothalamus. The expression levels of GnRH, FSH and LH mRNAs were down-regulated while the expression level of SS mRNA in hypothalamus was up-regulated in the ZYXHR-treated group. The GH mRNA in hypophysis and the IGF-Ⅰ mRNA in metaphysis were both down-regulated by ZYXHR. The YSTJR could promote the activity of GnRH neurons in hypothalamus through inhibiting the release of NPY in gonadotrophic area of hypothalamus, up-regulating the expression levels of GnRH, FSH, LH and GH mRNAs in hypophysis, and IGF-Ⅰ mRNA in metaphysis, while down-regulating the expression level of SS mRNA in hypothalamus.
The ZYXHR and YSTJR could both regulate the gonadotrophic and somatotrophic functions of hypothalamic-pituitary axis through modulating the neuroendocrine regulation and the gene expressions of GnRH and SS in hypothalamus, GH, FSH and LH in hypophysis, and IGF-Ⅰ in metaphysis. These may be the chief mechanisms of ZYXHR and YSTJR in modulating the course of pubertal development and ameliorating the skeletal development in children with precocious puberty.