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Purpose: To examine the association between semen characteristics and outcomes of intrauterine insemination (IUI)., Methods: This retrospective analysis examined 1380 IUI procedures involving 421 couples. The association of clinical pregnancy with pre- and post-wash sperm characteristics was assessed., Results: Pre- and post-wash sperm characteristics did not differ between IUI cycles that resulted in pregnancy and those that did not. When the motility of pre-wash sperm was below the normal range (<42%) established by the World Health Organization (WHO), the pregnancy rate was significantly lower. In the IUI cycles when post-wash sperm motility was below the WHO standard, pregnancy was not achieved. The frequency of improvement in post-wash sperm motility in repeated IUI cycles appeared to correlate with the success of future IUI cycles. At the fourth IUI cycle, pregnancy was not achieved unless the post-wash sperm motility was normal in at least two of three attempts. When post-wash sperm concentration was below the normal range, the woman's age did not affect the IUI outcomes., Conclusions: Sperm motility above the lower limit of the WHO criteria in post-wash semen samples is an important factor in IUI outcomes., Competing Interests: The authors declare no conflict of interest., (© 2024 The Authors. Reproductive Medicine and Biology published by John Wiley & Sons Australia, Ltd on behalf of Japan Society for Reproductive Medicine.)

Purpose: Relaxin-3 is a hypothalamic neuropeptide that belongs to the insulin superfamily. We examined whether relaxin-3 could affect hypothalamic Kiss-1, gonadotropin-releasing hormone (GnRH), and pituitary gonadotropin subunit gene expression., Methods: Mouse hypothalamic cell models, mHypoA-50 (originated from the hypothalamic anteroventral periventricular region), mHypoA-55 (originated from arcuate nucleus), and GT1-7, and the mouse pituitary gonadotroph LβT2 were used. Expression of Kiss-1, GnRH, and luteinizing hormone (LH)/follicle-stimulating hormone (FSH) β-subunits was determined after stimulation with relaxin-3., Results: RXFP3, a principle relaxin-3 receptor, was expressed in these cell models. In mHypoA-50 cells, relaxin-3 did not exert a significant effect on Kiss-1 expression. In contrast, the Kiss-1 gene in mHypoA-55 was significantly increased by 1 nmol/L relaxin-3. These cells also express GnRH mRNA, and its expression was significantly stimulated by relaxin-3. In GT1-7 cells, relaxin-3 significantly upregulated Kiss-1 expression; however, GnRH mRNA expression in GT1-7 cells was not altered. In primary cultures of fetal rat neuronal cells, 100 nmol/L relaxin-3 significantly increased GnRH expression. In pituitary gonadotroph LβT2, both LHβ- and FSHβ-subunit were significantly increased by 1 nmol/L relaxin-3., Conclusions: Our findings suggest that relaxin-3 exerts its effect by modulating the expression of Kiss-1, GnRH, and gonadotropin subunits, all of which are part of the hypothalamic-pituitary-gonadal axis., Competing Interests: All authors declare that they have no conflict of interest., (© 2019 The Authors. Reproductive Medicine and Biology published by John Wiley & Sons Australia, Ltd on behalf of Japan Society for Reproductive Medicine.)

Purpose: Accumulating evidence indicates that hypothalamic kisspeptin plays a pivotal role in the regulation of the hypothalamic-pituitary-gonadal (HPG) axis. In this study, the direct action of the gamma-aminobutyric acid (GABA) A receptor agonist on kisspeptin-expressing neuronal cells was examined., Methods: A hypothalamic cell model of rat hypothalamic cell line R8 (rHypoE8) cells and primary cultures of neuronal cells from fetal rat brains were stimulated with a potent and selective GABA A receptor agonist, muscimol, to determine the expression of the KiSS-1 gene., Results: Stimulation of the rHypoE8 cells with muscimol significantly increased the level of KiSS-1 messenger (m)RNA expression. The ability of muscimol to increase the level of KiSS-1 mRNA also was observed in the primary cultures of the neuronal cells from the fetal rat brains. The muscimol-induced increase in KiSS-1 mRNA expression was completely inhibited in the presence of the GABA A receptor antagonist. Although muscimol increased the expression of KiSS-1, the natural compound, GABA, failed to induce the expression of KiSS-1 in the rHypoE8 cells. Muscimol did not modulate gonadotropin-releasing hormone expression in either the rHypoE8 cells or the primary cultures of the fetal rat brains., Conclusions: This study's observations suggest that the activation of the GABA A receptor modulates the HPG axis by increasing kisspeptin expression in the hypothalamic neurons., Competing Interests: The authors declare no conflict of interest. Human and Animal Rights: This study's protocol was approved by the committee of the Experimental Animal Center for Integrated Research at Shimane University, Izumo, Japan. All the institutional and national guidelines for the care and use of laboratory animals were followed. This article does not contain any study with human participants that has been performed by any of the authors.