English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Prolactin is a pituitary hormone with a wide range of activities, including its involvement in the control of reproductive processes, related to the oestrous cycle, pregnancy and lactation (Freeman et al., 2000; Dusza and Ciereszko, 2007; Ignacak et al., 2012). In pigs, prolactin secretion during the oestrous cycle is altered. During the luteal phase, the plasma prolactin concentration is low, in the late luteal/early follicular phases characteristic and relatively short pulses correlated with prostaglandin F2α (PGF2α) surges are observed, and during the preovulatory period substantial increase in its secretion occurs (Dusza and Krzymowska, 1979; Brinkley, 1981; Van de Wiel et al., 1981; Dusza et al., 1988). A key role in the regulation of prolactin secretion is played by dopamine and thyreoliberin (TRH) ABSTRACT. The aim of the study was to determine an in vitro effect of specific agonists of opioid receptors on basal prolactin secretion and in the presence of dopamine or thyreoliberin (TRH) by porcine anterior pituitary cells. The cells were isolated from anterior pituitaries of gilts on days 8–10, 15–17 and 19–21 of the oestrous cycle and submitted to in vitro culture with mu-, deltaand kappaopioid receptor agonists – FK 33-824, DPLPE and U 50,488, respectively. Differentiated effects of the opioid agonists on prolactin secretion by isolated pituitary cells of gilts in chosen days of the oestrous cycle were shown. In the midluteal phase (days 8–10), a reduced prolactin secretion was demonstrated after activation of mu-, deltaand kappa-opioid receptors under all tested conditions. In the early follicular phase (days 15–17), the activation of mu-, deltaand kappa-opioid receptors increased prolactin secretion under basal conditions, as well as muand delta-opioid receptors – in the presence of TRH, but the stimulation of muand kappa-opioid receptors reduced the hormone secretion in the presence of dopamine. In the late follicular phase (days 19–21), kappa-opioid receptor agonist stimulated prolactin secretion under all tested conditions. The activation of muand delta-opioid receptors increased prolactin secretion under basal conditions and in the presence of dopamine, but decreased – in the presence of TRH. The results suggest a possibility of diverse participation of endogenous opioids, depending on stage of the oestrous cycle, in the modulation of prolactin secretion at the pituitary level in gilts during the oestrous cycle. Received: 19 January 2018 Revised: 26 April 2018 Accepted: 8 June 2018

journal of animal and feed sciences

The effects of &lt;i&gt;mu&lt;/i&gt;-, &lt;i&gt;delta&lt;/i&gt;- and &lt;i&gt;kappa&lt;/i&gt;-opioid receptor activation on &lt;i&gt;in vitro&lt;/i&gt; prolactin secretion by anterior pituitary cells of cyclic gilts