Neuroendocrine mechanism of onset of puberty. Sequential reduction in activity of inhibitory and facilitatory N-methyl-D-aspartate receptors.

Bourguignon, J P; Gérard, Arlette; González, Marta; Franchimont, P

doi:10.1172/jci116047

Cited by 69 publications

(44 citation statements)

References 50 publications

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“…In our in vitro conditions where the developmental acceleration of pulsatile GnRH secretion occurs between 10 and 25 d of age, the NMDA receptor sensitivity was assessed by the sensitivity to the use-dependent antagonist MK-801. Such a sensitivity was found to increase dramatically in a gonad-independent manner between d 10 and 25 (29,30) when a peak sensitivity is observed in consistency with the data obtained in vivo by Cicero et al (10).…”

Section: Sensitivity Of the Gnrh System To Glutamate In Relation To Psupporting

confidence: 90%

Control of Puberty by Excitatory Amino Acid Neurotransmitters and its Clinical Implications

Parent

Matagne

Bourguignon

2005

ENDO

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Excitatory amino acids, glutamate in particular, have a marked stimulatory effect on the reproductive axis, particulary at puberty. Glutamate, N-methyl-D-aspartate (NMDA), and kainite-stimulate gonadotropin-releasing hormone (GnRH) secretion in immature mammals and NMDA receptor stimulation results in precocious puberty in rats and monkeys. Puberty is characterized by an increased sensitivity of GnRH to glutamate as well as an increase in glutaminase activity in the hypothalamus. Glutamatergic and GABAergic regulation of GnRH secretion seem strongly interdependent around puberty. In addition to the transsynaptic glutamatergic regulation of GnRH secretion, a coordinated activity of glutamatergic neurons and astroglial cells has been shown to play an active role in puberty. The participation of kainate receptors in the estradiol-induced advancement of puberty suggest that these receptors may be involved in the estradiol-mediated activation of GnRH secretion at puberty. A case of precocious puberty associated with hyperglycinemia illustrates the NMDA involvement in puberty in humans. In this patient, the occurrence of precocious puberty was thought to result from excessive stimulation by glycine of the NMDA receptors linked to the GnRH neurons. Glutamate plays several roles in the hypothalamic mechanism of puberty as it has been shown in animal models, but there are still few clinical data supporting the role of glutamate in human puberty.

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Section: Sensitivity Of the Gnrh System To Glutamate In Relation To Psupporting

confidence: 90%

Control of Puberty by Excitatory Amino Acid Neurotransmitters and its Clinical Implications

Parent

Matagne

Bourguignon

2005

ENDO

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“…The onset of puberty takes place around the time of weaning by the age of 3 weeks as evidenced from onset of increase in serum levels of gonadal hormones (Maeda et al, 2000). It is preceded by attainment of a pubertal pattern of pulsatile GnRH secretion from hypothalamic explants (Bourguignon and Franchimont, 1984;Bourguignon et al, 1990Bourguignon et al, , 1992. In humans, puberty is characterized by an increase in LH and gonadal hormones.…”

Section: Pubertal Timing and Preceding Life Periods Across Speciesmentioning

confidence: 99%

“…Additional difficulties in human studies come from the limited access to endpoints of neuroendocrine maturation that is commonly assessed indirectly through LH measurement (Grandjean et al, 2012). With the aim of obtaining direct insight into the neuroendocrine changes involved in the mechanism of onset of puberty, we have developed a model enabling to study pulsatile GnRH secretion from hypothalamic explants (Bourguignon and Franchimont, 1984;Bourguignon et al, 1990Bourguignon et al, , 1992. Representative profiles of GnRH secretion are illustrated in Fig.…”

Section: Critical Windows Of Exposure To Endocrine Disrupters and Timmentioning

confidence: 99%

Developmental variations in environmental influences including endocrine disruptors on pubertal timing and neuroendocrine control: Revision of human observations and mechanistic insight from rodents

Parent

Franssen

Fudvoye

et al. 2015

Frontiers in Neuroendocrinology

156

140

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Puberty presents remarkable individual differences in timing reaching over 5 years in humans. We put emphasis on the two edges of the age distribution of pubertal signs in humans and point to an extended distribution towards earliness for initial pubertal stages and towards lateness for final pubertal stages. Such distortion of distribution is a recent phenomenon. This suggests changing environmental influences including the possible role of nutrition, stress and endocrine disruptors. Our ability to assess neuroendocrine effects and mechanisms is very limited in humans. Using the rodent as a model, we examine the impact of environmental factors on the individual variations in pubertal timing and the possible underlying mechanisms. The capacity of environmental factors to shape functioning of the neuroendocrine system is thought to be maximal during fetal and early postnatal life and possibly less important when approaching the time of onset of puberty.

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“…At 15 days of age, NMDA-receptor antagonists such as MK-801 cause a twofold increase in frequency of pulsatile GnRH secretion in vitro (Bourguignon et al 1992). In addition, in vivo administration of low MK-801 doses to prepubertal rats from 9 to 16 days of age results in precocious puberty (Bourguignon et al 1992), while similar treatment delays sexual maturation in older animals (Urbanski & Ojeda, 1990;McDonald & Wilkinson, 1990). Thus NMDA receptors appear to be involved in a dual control of GnRH secretion.…”

Section: MD Brown School Of Sport and Exercise Sciences University Omentioning

confidence: 99%

Symposium Proceedings

1995

The Journal of Physiology

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Starting with the earliest in vivo studies of the microcirculation, observers have been impressed with the variability and heterogeneity of microcirculation blood flow. The question I should like to address is how heterogeneity of microvascular perfusion influences transport of diffusible solutes, and how control of heterogeneity may contribute to regulation of blood-tissue exchange. Available exchange vessel surface area and inter-exchange vessel distances are controlled at the arteriolar level by the number of vessels open to the supply of arterial blood. When metabolic requirements are low, only a fraction of the exchange vessels in a vascular network are perfused; as metabolic activity increases, more exchange vessels are recruited. However, the efficiency with which available exchange vessel surface is utilized for diffusion of a given solute depends on the distribution of individual blood flow/permeability surface area ratios (Q/PS) in the network. Maximum efficiency (full utilization of available PS) is achieved when Q/PS is uniform.In vivo observations of red blood cell velocities show wide variation among individual exchange vessels of the same class (capillaries, postcapillary venules); presumably the same is true of plasma velocities. Flow velocity is only one of the factors that determines local transport; the critical parameter is the product of velocity and vessel radius divided by vessel length times solute permeability (v. r/ 1 P). The impression I get from published intra-vital microscope data is that this ratio may vary even more widely than velocity alone. Physiological measurements of solute transport in whole organs provide indirect support for broad heterogeneity of perfusion, at least in low metabolic states. In resting skeletal muscles the apparent (measured) PS products for 86Rb and 51Cr EDTA increase with increasing perfusion rate, approaching limiting values at high flow rates, as predicted for a heterogeneity perfused assemblage of exchange vessels. Estimated coefficients of variation (cv = S.D./mean) of Q/PS or v. r/ 1 P lie in the range 07-09.In heterogeneously perfused organs and tissues, the degree of heterogeneity (cv of Q/PS) and the total blood flow are potentially important secondary regulators of capillary transport, because they determine the efficiency with which the primary controlling factors, total blood flow and available exchange vessel surface area, are utilized (note that blood flow acts both directly and indirectly). Efficiency, defined as the ratio of apparent PS to the maximum PS at uniform perfusion, is inversely related to the degree of heterogeneity and directly related to the mean flow velocity. There is conflicting evidence in the literature concerning the degree to which alteration of Q/PS heterogeneity is involved in adaptive control of diffusion exchange. However, even with constant total PS and fixed heterogeneity, an increase in total blood flow can decrease the influence of heterogeneity on transport and thus contribute substantially to Berlin 33, Ger...

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Neuroendocrine mechanism of onset of puberty. Sequential reduction in activity of inhibitory and facilitatory N-methyl-D-aspartate receptors.

Cited by 69 publications

References 50 publications

Control of Puberty by Excitatory Amino Acid Neurotransmitters and its Clinical Implications

Control of Puberty by Excitatory Amino Acid Neurotransmitters and its Clinical Implications

Developmental variations in environmental influences including endocrine disruptors on pubertal timing and neuroendocrine control: Revision of human observations and mechanistic insight from rodents

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