Effects of Ghrelin upon Gonadotropin-Releasing Hormone and Gonadotropin Secretion in Adult Female Rats: In vivo and in vitro Studies

2005 ◽  
Vol 82 (5-6) ◽  
pp. 245-255 ◽  
Author(s):  
Rafael Fernández-Fernández ◽  
Manuel Tena-Sempere ◽  
Víctor M. Navarro ◽  
María L. Barreiro ◽  
Juan M. Castellano ◽  
...  
Keyword(s):  
Adult Female ◽  
Gonadotropin Releasing Hormone ◽  
In Vitro Studies ◽  
Female Rats ◽  
Gonadotropin Secretion ◽  
Releasing Hormone

scholarly journals Melatonin secretion from organ-cultured pineal glands of rats: modulation by gonadectomy and gonadotropin-releasing hormone agonist administration

2000 ◽  
pp. 387-392 ◽  
Author(s):  
B Ishizuka ◽  
S Fusama ◽  
K Hirai ◽  
T Hosaka ◽  
N Hamada ◽  
...  
Keyword(s):  
Adult Female ◽  
Gonadotropin Releasing Hormone ◽  
Female Rats ◽  
Male Rats ◽  
Female Rat ◽  
Serum Estradiol ◽  
Melatonin Secretion ◽  
Releasing Hormone ◽  
Gonadotropin Releasing Hormone Agonist

The objective of the study was to evaluate the effect of pretreatments such as gonadectomy in male and female rats, and gonadotropin-releasing hormone agonist (GnRHa) administration in female rats, on levels of secretion of melatonin, using an organ culture of pineal glands. Gonadectomy 2 weeks before the animal was killed increased the amount of melatonin secreted into the medium by the pineal glands of female rats but not of male rats. The increase in in vitro melatonin secretion after ovariectomy in female rats was prevented by estrogen replacement. Ovariectomy 3 and 4 weeks before death also significantly increased the amount of melatonin secretion. Administration of GnRHa 2 weeks before decapitation significantly decreased serum estradiol concentrations and significantly increased melatonin secretion by the pineal glands of female rat. GnRHa administration 3 or 4 weeks before decapitation also significantly decreased serum estradiol concentrations, but did not increase pineal secretion of melatonin. The results indicate that ovariectomy increases melatonin secretion from organ-cultured pineal glands and that this increase is suppressed by estrogen in adult female rats. In contrast, orchiectomy in male rats does not influence in vitro secretion of melatonin. These results suggest that the GnRH-gonadotropin system may participate in the regulation of pineal melatonin secretion in adult female rats.

scholarly journals Live View of Gonadotropin-Releasing Hormone Containing Neuron Migration

Endocrinology ◽  
2005 ◽  
Vol 146 (1) ◽  
pp. 463-468 ◽  
Author(s):  
Elizabeth P. Bless ◽  
Heather J. Walker ◽  
Kwok W. Yu ◽  
J. Gabriel Knoll ◽  
Suzanne M. Moenter ◽  
...  
Keyword(s):  
Real Time ◽  
Direct Evidence ◽  
Gonadotropin Releasing Hormone ◽  
Releasing Hormone ◽  
Reproductive Axis ◽  
Gnrh Neurons ◽  
Migratory Route ◽  
The Brain

Neurons that synthesize GnRH control the reproductive axis and migrate over long distances and through different environments during development. Prior studies provided strong clues for the types of molecules encountered and movements expected along the migratory route. However, our studies provide the first real-time views of the behavior of GnRH neurons in the context of an in vitro preparation that maintains conditions comparable to those in vivo. The live views provide direct evidence of the changing behavior of GnRH neurons in their different environments, showing that GnRH neurons move with greater frequency and with more changes in direction after they enter the brain. Perturbations of guiding fibers distal to moving GnRH neurons in the nasal compartment influenced movement without detectable changes in the fibers in the immediate vicinity of moving GnRH neurons. This suggests that the use of fibers by GnRH neurons for guidance may entail selective signaling in addition to mechanical guidance. These studies establish a model to evaluate the influences of specific molecules that are important for their migration.

252 EFFECT OF SUPERSTIMULATORY TREATMENT TO DONOR COWS IN OXYGEN CONSUMPTION OF MATURED OOCYTES

2013 ◽  
Vol 25 (1) ◽  
pp. 273
Author(s):  
K. Imai ◽  
S. Sugimura ◽  
M. Ohtake ◽  
Y. Aikawa ◽  
Y. Inaba ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Prostaglandin F2α ◽  
Gonadotropin Releasing Hormone ◽  
Oestrous Cycle ◽  
Control Group ◽  
Releasing Hormone ◽  
And Control ◽  
Bovine Oocytes

We previously reported that follicular wave synchronization and follicular growth treatment (FGT) before ovum pick-up (OPU) were effective in improving oocyte competence, which was associated with an increase in related embryos obtained by somatic cell nuclear transfer (Sugimura et al. 2012 Cell. Reprogram. 14, 29–37). However, oxygen consumption in oocytes remained unknown. The present study was designed to examine the differences in oxygen consumption between bovine oocytes obtained by OPU with or without FGT after in vitro maturation. Holstein dry cows (n = 8) were reared under the same feeding and environmental conditions. Two OPU sessions were conducted in each cow to collect immature oocytes, as described by Sugimura et al. (2012). The first OPU session (OPU group) was performed in cows on arbitrary days of the oestrous cycle, using a 7.5-MHz linear transducer with the needle connected to an ultrasound scanner. Follicles larger than 8 mm in diameter were then aspirated and a controlled internal drug release device (CIDR) was inserted on Day 5 (the day of the first OPU session = Day 0). Then 30 Armour units (AU) of FSH (Antrin, Kyoritsu Seiyaku, Tokyo, Japan) was administrated to cows twice a day from Day 7 to 10 in decreasing doses (6, 6, 4, 4, 3, 3, 2, 2 AU day–1). Cloprostenol (prostaglandin F2α; 0.75 mg) was administered in the morning of Day 9. The second OPU session (FGT-OPU group) was performed 48 h after prostaglandin F2α administration (Day 11), and only follicles larger than 5 mm in diameter were aspirated. The CIDR was removed from the cows just before OPU. Collected cumulus–oocyte complexes in the OPU and FGT-OPU groups were matured in vitro as described by Imai et al. [2006 J. Reprod. Dev. 52(Suppl.), S19–S29]. To collect in vivo-matured oocytes (control group), the CIDR was inserted into the cows on arbitrary days of the oestrous cycle (= Day 0), and oestradiol benzoate (0.8 mg) was administered on Day 1. The cows received the FGT treatment (as described above) from Day 6 to 10; however, the CIDR was removed in the evening of Day 8. Buserelin (gonadotropin-releasing hormone; 200 µg) was then administrated in the morning of Day 10, and OPU was performed at 24 h after gonadotropin-releasing hormone administration (Day 11). Oxygen consumption of matured oocytes was measured noninvasively with a scanning electron microscopy system (HV-405SP; Hokuto Denko Co., Tokyo, Japan). Data were analysed by ANOVA followed by a Tukey-Kramer test. There was no difference in the mean oxygen consumption between the FGT-OPU group (0.34 ± 0.02 × 10–14 mol–1, mean ± SEM) and control group (0.40 ± 0.01 × 10–14 mol–1). However, oxygen consumption in the FGT-OPU and control groups was significantly lower (P < 0.01) than that in the OPU group (0.50 ± 0.02 × 10–14 mol–1). These results revealed significantly lower oxygen consumption in OPU-derived in vitro-matured bovine oocytes after FGT treatment compared with those obtained without FGT treatment. Oxygen consumption of oocytes obtained from FGT-OPU was similar to that of in vivo-matured oocytes, which may reflect their cytoplasmic maturation status with high developmental competence.

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