Effects of central orexin A on gonadotropins and progesterone secretion in ewes during the luteal phase of the estrous cycle and during anestrus

Katarzyna Kirsz , Małgorzata Szczęsna , Aneta Bocheńska , Agnieszka Pietsch-Fulbiszewska , Natalia Sowińska , Natalia Kabała , Dorota Zięba-Przybylska


Prior studies, mainly on rodents demonstrated that orexin A (OXA) plays an important role in regulating the hypothalamo-pituitary-gonadal (HPG) axis. However, the results of those works have indicated that the central impact of OXA on the HPG axis may vary depending on the species or sex of the animal, the phase of the estrous cycle, or the experimental model system (in vivo vs. in vitro). The aim of the present study was to further investigate the role of OXA in the regulation of reproduction in seasonally breeding, intact, non-steroid-primed ewes during the luteal phase of the estrous cycle and during anestrus. We examined the effect of fourth-ventricle injections of OXA (0.3 μg/kg body weight) on plasma luteinizing hormone (LH), follicle-stimulating hormone (FSH) and progesterone concentrations and on the level of gonadotropin-releasing hormone receptor (GnRH-R) protein in the anterior pituitary (AP). Radioimmunoassays revealed that OXA treatments inhibited (P < 0.001) LH and FSH secretion during both examined periods and progesterone (P < 0.001) during the luteal phase. The influence of OXA on LH and FSH release may be partially attributable to the additional response of the pituitary to OXA, as, under the influence of OXA, the concentration of GnRH-R protein in the AP was downregulated during the luteal phase (P < 0.01) and during anestrus (P < 0.05). We conclude that OXA may be a negative regulator of gonadotropin secretion in intact, non-steroid-primed ewes in periods when the HPG axis is suppressed by negative feedback through steroid sex hormones.
Author Katarzyna Kirsz (FoAS / DoAB)
Katarzyna Kirsz,,
- Department of Animal Biotechnology
, Małgorzata Szczęsna (FoAS / DoAB)
Małgorzata Szczęsna,,
- Department of Animal Biotechnology
, Aneta Bocheńska
Aneta Bocheńska,,
, Agnieszka Pietsch-Fulbiszewska (VET)
Agnieszka Pietsch-Fulbiszewska,,
- University Centre for Veterinary Medicine UJ-UR
, Natalia Sowińska (VET)
Natalia Sowińska,,
- University Centre for Veterinary Medicine UJ-UR
, Natalia Kabała (VET)
Natalia Kabała,,
- University Centre for Veterinary Medicine UJ-UR
, Dorota Zięba-Przybylska (FoAS / DoAB)
Dorota Zięba-Przybylska,,
- Department of Animal Biotechnology
Journal seriesSmall Ruminant Research, ISSN 0921-4488, e-ISSN 1879-0941, (N/A 100 pkt)
Issue year2019
Publication size in sheets0.5
Keywords in EnglishOrexin A, Luteinizing hormone, Follicle-stimulating hormone, Progesterone, Gonadotropin-releasing hormone receptor, Intact and non-steroid-primed ewes
ASJC Classification3403 Food Animals; 1103 Animal Science and Zoology
URL https://www.sciencedirect.com/science/article/pii/S0921448819301208
Internal identifierWHiBZ/2019/32
Languageen angielski
Score (nominal)100
Score sourcejournalList
Publication indicators WoS Citations = 0; Scopus SNIP (Source Normalised Impact per Paper): 2016 = 0.947; WoS Impact Factor: 2018 = 1.21 (2) - 2018=1.351 (5)
Citation count*
Additional fields
FinansowanieThis work was supported by grunt from the H. Kołłątaj University of Agriculture in Krakow, Poland [grant number BM-4269/KBZ/2017].
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