Opioid modulation of LH secretion by pig pituitary cells in vitro

Barb, C. R.; Barrett, John B.; Wright, Jackson T.; Kraeling, Robert R.; Rampacek, George B.

doi:10.1530/jrf.0.0900213

Cited by 39 publications

(20 citation statements)

References 16 publications

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“…Before the experiment was started, we had postulated that response of β-EP to some stress factors such as abnormal calving or malnutrition is involved in delay in first ovulation. It has been reported that β-EP suppressed LH secretion from pituitary [34] and that naloxone, an opioid antagonist, increased pulsatile LH release in postpartum beef cows [35]. In this study, no effect of dystocia, retained placenta or fall in BCS on the plasma ir-β-EP level during the period between calving and first ovulation was found.…”

Section: Discussioncontrasting

confidence: 49%

Effects of Dystocia, Retained Placenta and Body Condition on Plasma .BETA.-Endorphin Profile in Periparturient Dairy Cows.

Osawa

Nakao

Moriyoshi

et al. 2000

Journal of Reproduction and Development

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Abstract. The aims of this study were to determine profiles of plasma immunoreactive β-endorphin (ir-β-EP) during peripartum period in dairy cows, and to examine whether dystocia, retained placenta or body condition affects the plasma ir-β-EP level. Blood samples were collected from 21 Holstein-Friesian cows from day 180 of pregnancy until first ovulation. The cows were classified into two groups based on calving conditions and ir-β-EP patterns at parturition. Seven out of the 21 cows had normal parturition and 14 cows had abnormal parturition (dystocia and/or retained placenta). The proportion of cows which had ir-β-EP elevation at parturition tended to be higher in cows with abnormal parturition (11/14; 79%) than in those with normal parturition (3/7; 42%). Plasma cortisol level increased at parturition both in cows with ir-β-EP elevation and in cows without ir-β-EP elevation at parturition. Postpartum ir-β-EP concentrations in plasma were similar between cows with normal parturition and those with abnormal parturition, and between cows which had lost their body condition score (BCS) after calving and those which had maintained their BCS. In conclusion, abnormal parturition may affect plasma ir-β-EP level at parturition but not postpartum period.

show abstract

Section: Discussioncontrasting

confidence: 49%

Effects of Dystocia, Retained Placenta and Body Condition on Plasma .BETA.-Endorphin Profile in Periparturient Dairy Cows.

Osawa

Nakao

Moriyoshi

et al. 2000

Journal of Reproduction and Development

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“…Preparation of pituitary cells and cell culture was performed essentially as described [29, 30]. In brief, following enzymatic digestion, cells were plated at 1 ml cell suspension/well (100,000 cells) in a 24-well cluster plate and cultured at 37°C in an humidified atmosphere containing 5% CO 2 .…”

Section: Methodsmentioning

confidence: 99%

Stimulation of Porcine Pituitary Luteinizing Hormone Release by Galanin: Putative Auto/Paracrine Regulation

Elsaesser¹

2001

Neuroendocrinology

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It has repeatedly been suggested that galanin acts within the anterior pituitary (AP) in an auto/paracrine manner to modulate luteinizing hormone (LH) release. Except for one recent report in the rat, evidence for this notion is absent. The purpose of this study was to investigate in the pig the effects of galanin on LH and growth hormone (GH) release and to evaluate putative local effects using various AP culture systems (monolayer, perifusion, reaggregates). Independent of age galanin dose dependently (0.05, 0.2, 1 µM) stimulated basal but not gonadotropin-releasing hormone (GnRH; ≧0.01 nM)-induced LH release. Neither basal nor GH-releasing hormone (GHRH)-stimulated GH release was affected at any age. Of 4 galanin receptor antagonists (0.2, 1 µM) tested C7 proved to have agonistic effects, whereas M40 and M15 (galantide) were ineffective in blocking galanin (0.2 µM)-induced LH secretion or affecting basal or GnRH-induced LH release. M32 [galanin (1–13) NPY (25–36) amide] inhibited (p ≤ 0.05) GnRH-induced LH release at doses of ≧2 µM, an effect which could be totally compensated by 1 µM galanin. However, the neuropeptide (NPY) antagonist BIBP 3226 (1 µM) partially overcame the effect of M32 (M32 is known to also bind to NPY receptors and NPY is inhibitory in the pig). In further studies using APs from preovulatory gilts a specific well-characterized galanin antiserum diluted 1:20 or 1:50 attenuated GnRH-induced LH release (p ≤ 0.05). However, an NPY antiserum (also affinity purified and at the same dilution) used as control unexpectedly inhibited GnRH (and galanin)-induced LH release as well, thus suggesting that attenuation of GnRH-induced LH release by galanin antiserum might be at least partly nonspecific. Furthermore 96-hour exposure of AP reaggregates to two types of porcine preprogalanin antisense oligodeoxynucleotides neither affected basal nor GnRH-induced LH release. In line with the failure to unequivocally prove paracrine effects of galanin, concentrations of galanin in AP cultures and AP culture medium were very low (≤2 pg galanin/10⁵ AP cells). In conclusion the present study provides some evidence to ascribe a hypophysiotropic role to galanin in regulating LH but not GH secretion in the pig. The study also points to the critical role of appropriate controls when trying to prove auto/paracrine control mechanisms within the anterior pituitary. Our findings do not provide convincing evidence to support the notion that intrapituitary galanin is involved in the fine tuning of LH secretion, at least in the preovulatory pig.

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“…Primary cell culture was performed as described in the previous studies [2,23,39]. Briefly, under sterile conditions, the pituitary glands were removed and the anterior lobe was immediately dissected from each pituitary gland.…”

Section: Animal and Primary Cell Culturementioning

confidence: 99%

Alteration of the miRNA expression profile in male porcine anterior pituitary cells in response to GHRH and CST and analysis of the potential roles for miRNAs in regulating GH

Qi¹,

Xi²,

Ye³

et al. 2015

Growth Hormone & IGF Research

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Opioid modulation of LH secretion by pig pituitary cells in vitro

Cited by 39 publications

References 16 publications

Effects of Dystocia, Retained Placenta and Body Condition on Plasma .BETA.-Endorphin Profile in Periparturient Dairy Cows.

Effects of Dystocia, Retained Placenta and Body Condition on Plasma .BETA.-Endorphin Profile in Periparturient Dairy Cows.

Stimulation of Porcine Pituitary Luteinizing Hormone Release by Galanin: Putative Auto/Paracrine Regulation

Alteration of the miRNA expression profile in male porcine anterior pituitary cells in response to GHRH and CST and analysis of the potential roles for miRNAs in regulating GH

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