Effect of undernutrition on pulsatile luteinizing hormone (LH) secretion in castrate and intact male rats using an ultrasensitive immunofluorometric LH assay

Dong, Qlhan

doi:10.1210/en.135.2.745

Cited by 17 publications

(5 citation statements)

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“…The serum and testicular testosterone concentrations were only decreased in the energy-restricted group, and these findings are consistent with previous studies [19 ± 21, 24]. Some authors have showed that energy restriction leads to a low serum LH concentrations [19,22,25,27]. So, the reduction observed in testosterone concentration in the energy-restricted group may be due to the lack of pituitary stimulus, leading to low testicular synthesis and therefore low serum concentration of testosterone.…”

Section: Discussionsupporting

confidence: 91%

Effects of Undernutrition on Serum and Testicular Testosterone Levels and Sexual Function in Adult Rats

Santos

Ferraz²,

Teixeira³

et al. 2004

Horm Metab Res

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The aim of this study was to evaluate testosterone concentrations, sexual behavior, and androgen receptor protein level in the testes of rats submitted to protein- and energy-restricted diets during 30 days. Adult male Wistar rats were assigned to one of the following groups: (C) control, diet with 23% of protein; (PR) protein-restricted, diet with 8% of protein; (ER) energy-restricted, diet with 23% of protein in restricted quantities. Mount number, ejaculation latencies and copulatory efficiency were evaluated to determine sexual behavior. At the end of the experiment, the animals were sacrificed to determine serum and testicular testosterone concentrations as well as testicular androgen receptor protein level. Compared to the C group, the ER group presented a significant decrease in body (36%), testis (20%) and epididymis (14%) weights in serum (78%) and testicular (68%) testosterone concentrations as well as in copulatory efficiency (26%). On the other hand, the ER group presented a significant increase in mount number (114%) and ejaculatory latency (62%). The androgen receptor protein levels were significantly reduced in both PR and ER groups (41% and 74%, respectively). This is the first paper to demonstrate that the effect of undernutrition on reproduction is not related to reduced protein intake but caloric restriction. Also, in caloric restriction, there is a relationship between sex behavior, androgen receptors, and testosterone concentration.

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Section: Discussionsupporting

confidence: 91%

Effects of Undernutrition on Serum and Testicular Testosterone Levels and Sexual Function in Adult Rats

Santos

Ferraz²,

Teixeira³

et al. 2004

Horm Metab Res

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“…Contrary to what was found in prepubertals, in peripubertal 30day-old male rats it was observed an increase in the LH and FSH serum levels, However these changes do not come with a change in the GnRH hypothalamic release, being a possible explanation that at this age, 4-MBC might produce stimulatory eff ect acting directly on the adenohypophysis secretion of gonadotropins. Another possibility would be that the administration of 4-MBC might cause a change in the pulse frequency of the GnRH neuron, which is not under study in this work, and that was not refl ected in the total amount of hormone in the culture media due to the fact that alterations in the pulsatility of GnRH or LH are not always refl ected in concentrations changes of said hormones ( Dong et al, 1994 ;Kaji et al, 1998 ). Meanwhile, testicular weight did not change at this age in both groups.…”

Section: Exposure To High Doses (100 and 500 Mg / Kg / Day)mentioning

confidence: 86%

Impact of 4-Methylbenzylidene-camphor (4-MBC) during Embryonic and Fetal Development in the Neuroendocrine Regulation of Testicular Axis in Prepubertal and Peripubertal Male Rats

Szwarcfarb²,

Ml³

et al. 2009

Exp Clin Endocrinol Diabetes

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4-Methylbenzylidene-camphor (4-MBC), an UV-B ray filter, belongs to the endocrine disrupters involved with alterations in the reproductive axis. Our target was to study the effect of 4-MBC on the neuroendocrine parameters that regulate reproduction in prepubertal and peripubertal male rats, which received this disrupter during embryonic and fetal development. 4-MBC was administered (sc) to female rats since pregnancy onset in doses of 20, 100 and 500 mg/kg/day. The litters were sacrificed at 15 or 30 days old to determine testicular weight, gonadotropin and prolactin serum levels and also GnRH and amino acids release from the hypothalamus. The exposure to 20 mg/kg/day only increased the LH serum levels in 30-day-old males. Doses of 100 and 500 mg/kg/day caused a decrease in testicular weight and in LH, GnRH and glutamate levels, in prepubertal rats (15-day-old specimens), and an increase in, gonadotropin (LH and FSH) con-centration and aspartate levels in peripubertal rats (30-day-old specimens), without changes in testicular weight. Prolactinaemia remained unaltered in all groups. Results obtained show that the administration of high doses of 4-MBC during embryonic and fetal stage inhibits the testicular axis in male rats during the prepubertal stage and stimulates it during peripubertad stage. On the other hand in the case of low doses no significant effects were observed.

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“…Maintenance of the reproductive cycle is critically dependent upon the occurrence of pulses of luteinizing hormone (LH). Examples of stressors that suppress the pulsatile release of LH in rats include restraint (3), electric shocks (4), fasting (5), under‐nutrition (6), hypoglycaemia (7, 8) and glucoprivation (9, 10). Restraint stress also blocks the pro‐oestrous surge of LH (11).…”

mentioning

confidence: 99%

Studies on the Neuroanatomical Basis for Stress‐Induced Oestrogen‐Potentiated Suppression of Reproductive Function: Evidence Against Direct Corticotropin‐Releasing Hormone Projections to the Vicinity of Luteinizing Hormone‐Releasing Hormone Cell Bodies in Female Rats

Hahn

Κalamatianos

Coen

2003

J Neuroendocrinology

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Various studies implicate corticotropin‐releasing hormone (CRH) as a mediator for the inhibitory effects of stress on reproduction. This study was designed to elucidate the underlying neuroanatomy. The retrograde tracer cholera toxin was picospritzed into the vicinity of the luteinizing hormone‐releasing hormone (LHRH) perikarya. CRH neurones were examined for the tracer in the medial preoptic nucleus (MPO), bed nucleus of the stria terminalis (BST), paraventricular nucleus (PVN), central amygdaloid nucleus (CeM), parabrachial nucleus (PB) and additional locations. Retrograde label was not detected in CRH neurones at any of these sites; nevertheless, in the MPO and PB, abundant retrogradely‐labelled perikarya intermingled with CRH neurones. In the BST, CeM and PVN, sites containing major CRH cell populations, retrogradely‐labelled cells were scarce or absent; however, retrograde labelling was found in adjacent regions: lateral septum, medial amygdaloid nucleus and areas bordering the PVN. Double‐label in situ hybridization for the mRNAs for LHRH and the CRH type‐1 receptor (CRH‐R1) identified the receptor transcript at sites rostral and lateral to the LHRH neurones (in the vertical and horizontal limbs of the diagonal band) but not in the LHRH neurones. Given the ability of oestrogen to potentiate stress‐induced suppression of LH release, the identification of CRH neurones immunoreactive for oestrogen receptor (ER)α in the MPO and for ERβ in the caudal PVN may be significant. In this context, it is also noteworthy that CRH neurones within the MPO and PB which are, respectively, immunopositive and immunonegative for ERα, lie within the vicinity of retrogradely‐labelled cells. The present findings suggest that the means by which CRH may mediate inhibitory effects of stressors on LH release do not involve direct CRH projections to LHRH neurones; the indirect means for such regulation, and the sites at which oestrogen may potentiate the inhibitory response, remain to be established.

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Effect of undernutrition on pulsatile luteinizing hormone (LH) secretion in castrate and intact male rats using an ultrasensitive immunofluorometric LH assay

Cited by 17 publications

References 0 publications

Effects of Undernutrition on Serum and Testicular Testosterone Levels and Sexual Function in Adult Rats

Effects of Undernutrition on Serum and Testicular Testosterone Levels and Sexual Function in Adult Rats

Impact of 4-Methylbenzylidene-camphor (4-MBC) during Embryonic and Fetal Development in the Neuroendocrine Regulation of Testicular Axis in Prepubertal and Peripubertal Male Rats

Studies on the Neuroanatomical Basis for Stress‐Induced Oestrogen‐Potentiated Suppression of Reproductive Function: Evidence Against Direct Corticotropin‐Releasing Hormone Projections to the Vicinity of Luteinizing Hormone‐Releasing Hormone Cell Bodies in Female Rats

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