The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology

Warsaw, Poland

The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology

Warsaw, Poland
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Ciechanowska M.O.,The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology | Lapot M.,The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology | Mateusiak K.,The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology | Paruszewska E.,The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology | And 2 more authors.
Canadian Journal of Physiology and Pharmacology | Year: 2017

This study was performed to explain how the molecular processes governing the biosynthesis of gonadotropinreleasing hormone (GnRH) and GnRH receptor (GnRHR) in the hypothalamic–pituitary unit are reflected by luteinizing hormone (LH) secretion in sheep during anoestrous period and during luteal and follicular phases of the oestrous cycle. Using an enzyme-linked immunosorbent assay (ELISA), we analyzed the levels of GnRH and GnRHR in preoptic area (POA), anterior (AH) and ventromedial hypothalamus (VM), stalk–median eminence (SME), and GnRHR in the anterior pituitary gland (AP). Radioimmunoassay has also been used to define changes in plasma LH concentrations. The study provides evidence that the levels of GnRH in the whole hypothalamus of anoestrous ewes were lower than that in sheep during the follicular phase of the oestrous cycle (POA: p < 0.001, AH: p < 0.001, VM: p < 0.01, SME: p < 0.001) and not always than in luteal phase animals (POA: p < 0.05, SME: p < 0.05). It has also been demonstrated that the GnRHR amount in the hypothalamus–anterior pituitary unit, as well as LH level, in the blood in anoestrous ewes were significantly lower than those detected in animals of both cyclic groups. Our data suggest that decrease in LH secretion during the long photoperiod in sheep may be due to low translational activity of genes encoding both GnRH and GnRHR. © 2017 Canadian Science Publishing. All rights reserved.


Ciechanowska M.,The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology | Lapot M.,The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology | Mateusiak K.,The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology | Paruszewska E.,The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology | And 3 more authors.
Reproduction in Domestic Animals | Year: 2016

The effects of prolonged, intermittent infusion of β-endorphin or naloxone into the third cerebral ventricle of follicular-phase ewes on the expression of genes encoding GnRH and GnRHR in the hypothalamus and GnRHR in the anterior pituitary gland (AP) were examined by an enzyme-linked immunoabsorbent assay. Activation or blockade of μ-opioid receptors significantly decreased or increased the GnRH concentration and GnRHR abundance in the hypothalamus, respectively, and affected in the same way GnRHR quantity in the AP gland. The changes in the levels of GnRH and GnRHR after treatment with β-endorphin as well as following action of naloxone were reflected in fluctuations of plasma LH concentrations. On the basis of these results, it is suggested that β-endorphinergic system in the hypothalamus of follicular-phase ewes affects directly or via β-endorphin-sensitive interneurons GnRH and GnRHR biosynthesis leading to suppression in secretory activity of the hypothalamic-pituitary axis. © 2016 Blackwell Verlag GmbH


Ciechanowska M.,The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology | Lapot M.,The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology | Antkowiak B.,The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology | Mateusiak K.,The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology | And 4 more authors.
Animal Reproduction Science | Year: 2016

Using an ELISA assay, the levels of GnRH and GnRHR were analysed in the preoptic area (POA), anterior (AH) and ventromedial hypothalamus (VM), stalk/median eminence (SME); and GnRHR in the anterior pituitary gland (AP) of non-breeding and breeding sheep subjected to short-term or prolonged stress. The ELISA study was supplemented with an analysis of plasma LH concentration. Short-term footshock stimulation significantly increased GnRH levels in hypothalamus in both seasons. Prolonged stress elevated or decreased GnRH concentrations in the POA and the VM, respectively during anoestrus, and lowered GnRH amount in the POA-hypothalamus of follicular-phase sheep. An up-regulation of GnRHR levels was noted in both, anoestrous and follicular-phase animals. In the non-breeding period, a prolonged stress procedure increased GnRHR biosynthesis in the VM and decreased it in the SME and AP, while in the breeding time the quantities of GnRHR were significantly lower in the whole hypothalamus. In follicular-phase ewes the fluctuations of GnRH and GnRHR levels under short-term and prolonged stress were reflected in the changes of LH secretion, suggesting the existence of a direct relationship between GnRH and GnRH-R biosynthesis and GnRH/LH release in this period. The study showed that stress was capable of modulating the biosynthesis of GnRH and GnRHR; the pattern of changes was dependent upon the animal's physiological state and on the time course of stressor application. The obtained results indicate that the disturbances of gonadotropin secretion under stress conditions in sheep may be due to a dysfunction of GnRH and GnRHR biosynthetic pathways. © 2016 Elsevier B.V.


PubMed | Polish Academy of Sciences and The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology
Type: | Journal: Animal reproduction science | Year: 2016

Using an ELISA assay, the levels of GnRH and GnRHR were analysed in the preoptic area (POA), anterior (AH) and ventromedial hypothalamus (VM), stalk/median eminence (SME); and GnRHR in the anterior pituitary gland (AP) of non-breeding and breeding sheep subjected to short-term or prolonged stress. The ELISA study was supplemented with an analysis of plasma LH concentration. Short-term footshock stimulation significantly increased GnRH levels in hypothalamus in both seasons. Prolonged stress elevated or decreased GnRH concentrations in the POA and the VM, respectively during anoestrus, and lowered GnRH amount in the POA-hypothalamus of follicular-phase sheep. An up-regulation of GnRHR levels was noted in both, anoestrous and follicular-phase animals. In the non-breeding period, a prolonged stress procedure increased GnRHR biosynthesis in the VM and decreased it in the SME and AP, while in the breeding time the quantities of GnRHR were significantly lower in the whole hypothalamus. In follicular-phase ewes the fluctuations of GnRH and GnRHR levels under short-term and prolonged stress were reflected in the changes of LH secretion, suggesting the existence of a direct relationship between GnRH and GnRH-R biosynthesis and GnRH/LH release in this period. The study showed that stress was capable of modulating the biosynthesis of GnRH and GnRHR; the pattern of changes was dependent upon the animals physiological state and on the time course of stressor application. The obtained results indicate that the disturbances of gonadotropin secretion under stress conditions in sheep may be due to a dysfunction of GnRH and GnRHR biosynthetic pathways.

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