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1

Leptyna i jej udzial w regulacji procesow rozrodu i metabolizmu u przezuwaczy

100%
Zieba D. A.
Zeszyty Naukowe Akademii Rolniczej w Krakowie. Rozprawy
|
2005
|
nr 303
1-95
2

Kisspeptyna - neurohormon o kluczowej roli w rozrodzie

63%
Klocek-Gorka B., Zieba D. A.
Medycyna Weterynaryjna
|
2008
|
tom 64
|
nr 09
1087-1090
Kisspeptin is a newly-discovered neurohormone, which is secreted from the hypothalamus. Initially it was thought that kisspeptin takes part in metastasis suppression. However, nowadays it is known that this hormone plays an essential role in the modulation of the hypothalamus-pituitary-gonadal axis. It has been demonstrated that mutation in the gene encoding kisspeptin’s receptor causes hypogonadotrophic hypogonadism and infertility in animals and humans. It is well established that kisspeptin may directly stimulate hypothalamic neurons. In addition, this neurohormone directly affects the pituitary and gonads. In the current review the authors sum up all information about different ways of direct and indirect effects of kisspeptin on reproductive processes and also present a novel insight into the mechanism responsible for the feedback loop of estrogen and androgen in mammals.
3

Interakcje pomiedzy leptyna i prolaktyna u owiec

63%
Szczesna M., Zieba D. A.
Medycyna Weterynaryjna
|
2008
|
tom 64
|
nr 08
973-976
The capacity of an organism to cope with harsh conditions is the result of long evolutionary processes and interactions between hormones involved in reproduction (LH, FSH, GnRH), metabolic processes (leptin, prolactin, growth hormone) and seasonality (melatonin). The mechanism through which animals adjust energy intake and expenditure according to the demands of the organism in different physiological status is still unknown. In the literature, information about interaction between leptin and prolactin is scarce and contradictory. Leptin plays a crucial role in the regulation of energy homeostasis or food intake and, as well as prolactin, it is a hormone of importance as an endocrine mediator. Day length and lactation are able to affect leptin and prolactin expression and secretion, but also modulate the correlation between them. The present review summarises research on interaction between leptin and prolactin, starting from the direct effects, through the influence of seasonality and lactation. The complete understanding of mechanisms involved in the interactions may be very useful not only in animal breeding, but also in developing effective therapies in human obesity, eating disorders and infertility.
4

Wybrane czynniki podwzgórzowe integrujące rozród i kontrolę bilansu energetycznego u zwierząt

63%
Kirsz K., Zieba D. A.
Medycyna Weterynaryjna
|
2012
|
tom 68
|
nr 01
Mammalian reproduction is the most energy-consuming biological process. However, chronic dietary energy deficits, as well as energy surpluses can impair reproductive capacity, including the ability to produce viable gametes, and interrupt pregnancy or lactation. Thus, there is no doubt that the mechanisms controlling energy balance are integrated with those that control reproduction. There is functional evidence for a crucial connection between those mechanisms in the gonadotropin-releasing hormone (GnRH) cells of the hypothalamus, which are part of the hypothalamo-pituitary-gonadal (HPG) axis. Recent research has shown that the multiple hypothalamic peptidergic systems responsible for the homeostatic control of energy balance are involved in signaling to GnRH neurons. This group includes neuropeptyd Y (NPY), melanin-concentrating hormone (MCH), proopiomelanocortin (POMC), as well as periphery factors, such as leptin, ghrelin and insulin. However, the discovery of kisspeptin and gonadotropin-inhibitory hormone (GnIH) sheds a new light on mechanisms by which reproductive activity is regulated, also in the context of diurnal and annual photoperiod-driven cycles of mammals’ energy requirements. Thus, it seems clear that those two peptides are very important in linking the processes of energy balance maintenance and reproduction.
5

Kisspeptyna - neurohormon regulujacy sezonowosc rozrodu

63%
Klocek-Gorka B., Zieba D. A.
Przegląd Hodowlany
|
2008
|
tom 76
|
nr 08
7-9
6

Psychoneuroimmunologiczne podloze zooterapii

51%
Dziurdzia A., Flaga J., Merchut J., Zieba D. A.
Wszechświat
|
2007
|
tom 108
|
nr 10-12
296-299
7

Cross-talk between leptin, ghrelin and orexins in the central nervous system of seasonal animals - a review

51%
Kirsz K., Szczesna M., Borsuk A., Zieba D. A.
Annals of Animal Science
|
2017
|
tom 17
|
nr 2
8

High doses of copper administered to sheep and the postnatal adaptation of the twin lambs

51%
Murawski M., Wronska-Fortuna D., Zieba D. A.
Annals of Animal Science
|
2010
|
tom 10
|
nr 4
9

Gestational profile of suppressor of cytokine signaling-3 (SOCS-3) transcripts in ovine brain and anterior pituitary

51%
Szczesna M., Kirsz K., Zieba D. A.
Acta Neurobiologiae Experimentalis
|
2017
|
tom 77
|
nr Suppl.1
10

Ghrelin regulates nightly melatonin secretion from sheep pineal gland in a TPH1- independent manner: An in vitro study

51%
Kirsz K., Szczesna M., Zieba D. A.
Acta Neurobiologiae Experimentalis
|
2017
|
tom 77
|
nr Suppl.1
INTRODUCTION: Several studies suggest that ghrelin (GHRL) has neurobiological effects that extend beyond the control of food intake. Our previous results confirmed that GHRL modulates the secretory activity of the pineal gland (PG) through nocturnal melatonin (MEL) secretion in sheep, which are seasonally reproductive animals. AIM(S): We investigated the effects of GHRL and seasons on the tryptophan 5-hydroxylase 1 (TPH1) expression in sheep PG. TPH1 is the rate-limiting enzyme in the biosynthesis of serotonin (MEL precursor). METHOD(S): Glands were collected after sunset from 8 ewes during long-day season (LD; May) and from 8 ewes during short-day season (SD; November). The PG were transected into strips (n=72), with each equilibrated in 1.0 ml of DMEM for 60 min, followed by a 4-hr incubation in a gas-liquid interface in medium alone (control) or in medium containing GHRL (10 ng/ml). After each hr of incubation, selected explants were frozen in liquid nitrogen and stored at −80°C for Real‑time PCR and ELISA. Sixty minutes (light intensity: 400 lux). During following 9 experimental days blue part of the spectrum was blocked by yellow filter (cut off at 525 nm). Locomotor activity, core body temperature and their circadian parameters were compared between light conditions. RESULTS: After blue light blockage amplitude and robustness of the locomotor activity rhythm decreased. A significant reduction in the mean level of activity was observed in the dark phase. Moreover, the mesor of the rhythm of core body temperature decreased, core body temperature was reduced both in the light and the dark phase. CONCLUSIONS: Blue light deprivation results in disturbances in circadian rhythmicity in non-genetically modified rats with fully functional retina. Observed changes resemble those found in depressed patients, suggesting that not only light intensity but also its spectral composition matters. FINANCIAL SUPPORT: Supported by 2013/08/W/ NZ3/00700.
11

Srodowiskowe i fizjologiczne uwarunkowania sezonowosci rozrodu owiec

51%
Klocek B. A., Zieba D. A., Wierzchos E.
Przegląd Hodowlany
|
2006
|
tom 74
|
nr 10
19-22
12

Zalezne od fotoperiodu oddzialywanie egzogennej leptyny na poziom uwalniania melatoniny u owiec

51%
Klocek-Gorka B., Wozniak M., Zieba D. A., Murawski M.
Zeszyty Naukowe Akademii Rolniczej w Krakowie. Sesja Naukowa
|
2007
|
tom 93
363-368
13

Pattern of follicular development in high fecundity Olkuska ewes during the estrous cycle

51%
Zieba D. A., Murawski M., Schwarz T., Wierzchos E.
Reproductive Biology
|
2002
|
tom 02
|
nr 1
14

Transcript abundances of the prolactin receptor, the leptin receptor and their major suppressor in the sheep mammary gland during pregnancy and lactation

51%
Szczesna M., Kirsz K., Nowakowski M., Zieba D. A.
Annals of Animal Science
|
2020
|
tom 20
|
nr 4
15

Seasonal plasticity of the brain: the use of sheep model to study leptin resistance and obesity

51%
Zieba D. A., Szczesna M., Kirsz K., Molik E.
Acta Neurobiologiae Experimentalis
|
2017
|
tom 77
|
nr Suppl.1
The core of the leptin resistance hypothesis promulgated several years ago to explain obesity as a result of environmental causes consists of two tenets: the extinction of leptin-induced intracellular signaling downstream of leptin binding to the long form of the neuronal receptor LTRb in the hypothalamus and the impedance to leptin entry imposed at the blood-brain barrier (BBB). A recent comprehensive investigation concluded that a central leptin insufficiency associated with obesity can be attributed to a decreased efficiency of BBB leptin transport and not to leptin insensitivity within the hypothalamus. Interestingly, anorectic leptin’s effects are counteracted in some individuals by a natural resistance associated with hyperleptinemia, which is related to changes in hypothalamic sensitivity to leptin associated with, for example, seasonal reproduction, malnutrition or obesity. In sheep, it was observed that the hypothalamus is resistant to leptin in some periods, and this phenomenon is related to the adaptation of these animals to annual changes in energy supply and demand. However, a broad range of ambiguities exists regarding the implications that the intracellular signaling of signal transducer and activator of transcription-2/ suppressor of cytokine signaling 3 (STAT2/SOCS3) imparts central leptin resistance. Furthermore, several plausible alternative possibilities have been proposed, such as compensatory functional and anatomical reorganizations in the appetite regulating network (ARN), rearrangements in the afferent hormonal feedback signaling involved in weight homeostasis and modifications in leptin transport to the hypothalamus across the BBB. Taken together, these observations suggest that the contention that impaired intracellular signaling downstream of leptin entry into the ARN expedites environmentally induced obesity remains unsubstantiated and requires further evidence. FINANCIAL SUPPORT: Supported by NCN grants No. 2013/09 /B/NZ4/01532 and No. 2015/19/B/NZ9/01314.
16
Content available remote

Leptin as a nutritional signal regulating appetite and reproductive processes in seasonally-breeding ruminants

51%
Zieba D. A., Szczesna M., Klocek-Gorka B., Williams G. L.
Journal of Physiology and Pharmacology. Supplement
|
2008
|
tom 59
|
nr 9
7-18
17

Induction of the secretion of LH and GH by orexin A and ghrelin is controlled in vivo by leptin and photoperiod in sheep

45%
Kirsz K., Szczesna M., Molik T., Misztal T., Zieba D. A.
Annals of Animal Science
|
2017
|
tom 17
|
nr 1
18

Photoperiodic conditions as a factor modulating leptin influence on pro-inflammatory cytokines and their receptors gene expression in ewe’s aorta

39%
Krawczynska A., Antushevich H., Bochenek J., Wojtulewicz K., Pawlina B., Herman A. P., Zieba D. A.
Journal of Animal and Feed Sciences
|
2019
|
tom 28
|
nr 2
Atherosclerosis, a chronic inflammation state of the aorta, is characterised by increased levels of pro-inflammatory cytokines (tumour necrosis factor alpha (TNFα), interleukin (IL)-1β, IL-6). Sheep is used in both cardiovascular and immunological studies; besides, ‘long-day’ ewe can be a model of leptin resistance state. The aim of the study was to examine whether photoperiodic conditions (long-day (LD) and short-day (SD) seasons) are a key factor modulating exogenous leptin influence on pro-inflammatory cytokines and their receptors gene expression in aorta of ewe’s with or without prior induction of acute inflammation. The experiment was conducted on 48 ewes during SD and LD seasons which were randomly divided into 4 groups: control; with LPS injection (400 ng/kg of body weight (BW)); with leptin injection (20 μg/kg BW); and with LPS and 30-min later leptin injection. Three hours after LPS/control treatment animals were euthanized to collect the thoracic aorta samples. In both seasons leptin injection intensified LPS-induced increase in IL1B gene expression but only in SD season leptin injection increased IL1R1 and IL1R2 gene expressions. The leptin injection increased IL6 gene expression but only in SD season. In the LD season leptin enhanced the LPS effect on IL6 gene expression. Neither TNFA nor its receptors gene expression was influenced by leptin regardless of season. In the thoracic aorta tissue an exogenous leptin exerts effect on pro-inflammatory cytokines and their receptors gene expression; however in ewe this influence depends on photoperiodic conditions. Moreover, leptin can moderate progression of the inflammation reaction in this tissue.
19
Content available remote

The role of orexin A in the control of prolactin and growth hormone secretions in sheep - in vitro study

39%
Molik E., Zieba D. A., Misztal T., Romanowicz K., Wszola M., Wierzchos E., Nowakowski M.
Journal of Physiology and Pharmacology. Supplement
|
2008
|
tom 59
|
nr 9
91-100
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