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Shiping Su, Xiaoxia Sun, Xiuhong Zhou, Fuigui Fang and Yunsheng Li

; two slices per hypothalamic nuclei). * P <0.05, ** P <0.01. Discussion GnRH and thymulin are the two keys signaling molecules that link the reproductive axis and the immune axis. Immunization against GnRH is an effective method of limiting reproduction

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H. F. Urbanski, M. M. Fahy and P. M. Collins

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.

Journal of Endocrinology (1993) 137, 247–252

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Christopher J Scott, Jessica L Rose, Allan J Gunn and Briony M McGrath

://doi.org/10.1111/j.1365-2826.2010.02022.x ) 20456610 Caraty A Decourt C Briant C Beltramo M 2012 Kisspeptins and the reproductive axis: potential applications to manage reproduction in farm animals . Domestic Animal Endocrinology 43 95 – 102

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Nilli Zmora, Ten-Tsao Wong, John Stubblefield, Berta Levavi-Sivan and Yonathan Zohar

inhibitory effect of dynorphin-A ( Gallo 1990 , Grachev et al . 2014 ) on the GnRH pulse are widely acknowledged, the effect of NKB remains controversial as studies have reported both NKB inhibition and stimulation of the reproductive axis ( Sandoval

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Fazal Wahab, Ikram Ullah Khan, Ignacio Rodriguez Polo, Hira Zubair, Charis Drummer, Muhammad Shahab and Rüdiger Behr

Introduction The gonadal function is controlled by a complex interaction of regulatory signals, involving hypothalamus, pituitary and the gonads themselves. Altogether, they form the reproductive axis (a.k.a. the hypothalamic

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H Kadokawa, M Matsui, K Hayashi, N Matsunaga, C Kawashima, T Shimizu, K Kida and A Miyamoto

). However, the molecular and cellular mechanisms linking the reproductive axis and somatotropic axis at the levels of the brain and pituitary during puberty still remain incompletely understood. The fact that the kisspeptin–GPR54 system has an important role

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Tony M Plant

1259–1305. Eds TM Plant & AJ Zeleznik. San Diego, CA, USA. Copyright Elsevier (2015). It is probably no exaggeration to say that the discovery of the impact of loss-of-function mutations in GPR54 on the reproductive axis led to a profound and much

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M J Vazquez, I Velasco and M Tena-Sempere

); findings that were later confirmed also for Kiss1 inactivation ( d’Anglemont de Tassigny et al. 2007 , Topaloglu et al. 2012 ). While a detailed recapitulation of the major features of kisspeptins as master regulators of the reproductive axis exceeds

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Arturo Hernandez and M Elena Martinez

-/- mice exhibit proliferation arrest of SCs and premature lumen formation in seminiferous tubules ( Martinez et al . 2016 b ). They further show impaired spermatogenesis, delayed puberty, poor fertility and hormonal abnormalities in the reproductive axis

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Helen L Henderson, Julie Townsend and Domingo J Tortonese

develop in vivo in some circumstances to counteract the suppressive effects of hyperprolactinaemia on the reproductive axis reported by others and/or the robust treatment effects observed here in vitro . In conclusion, this study has demonstrated the