• Animal Bioscience
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• v.37 no.10
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• pp.1712-1725
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• 2024

Objective: The objective of this study was to investigate the effects of prolactin (PRL) on the proliferation and apoptosis of ovine ovarian granulosa cells (GCs) and the secretion of estrogen (E₂) and progesterone (P₄), as well as to explore the effects of PRL on related genes and proteins. Methods: We isolated ovarian GCs from 1-year-old small-tail Han sheep and identified PRL receptor (PRLR) on ovaries and follicle stimulating hormone receptor (FSHR) on ovarian GCs, respectively, using immunohistochemistry. PRL (0, 0.05, 0.50, 5.00 ㎍/mL) were added to GCs in vitro along with FSH, cell proliferation was measured by cell counting Kit-8 (CCK-8) and apoptosis by flow cytometry. The measurement of E₂ and P₄ content by enzyme-linked immunosorbent assays after 48 h and 72 h. The expression of functional genes and proteins was identified by real-time quantitative polymerase chain reaction (RT-qPCR) and Western-blot after 48 h. Results: PRLR was expressed in both follicular GCs and corpus luteum, whereas FSHR was expressed specifically. The proliferative activity was lower on day 1 while higher on day 4 and day 5. The apoptosis rate of GCs in the 0.05 ㎍/mL group was significantly higher than that in the control group after treatment with PRL for 24 h (p<0.05). Compared with the control group, the secretion of E₂ in GCs was reduced significantly (p<0.05) in PRL treatment for 48 h and 72 h, while the secretion of P₄ was significantly increased (p<0.05). The mRNA expression levels of PRLR, FSHR, LHR, CYP11A1, HSD3B7, and STAR were significantly higher than those in the control group (p<0.01), and the relative abundance of BCL2 in all PRL group were increased after PRL treatment. Conclusion: PRL promoted the proliferation of GCs and supraphysiological concentrations inhibited apoptosis caused by down-regulation of BAX and up-regulation of BCL2. PRL inhibited E₂ by down-regulating CYP19A1 and promoted P₄ by up-regulating CYP11A1, STAR, and HSD3B7.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.4
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• pp.571-579
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• 2016

In this work, we prepared a panel of monoclonal anti-idiotypic antibodies to ovine prolactin (oPRL) by the hybridoma technique. Among these antibodies, one anti-idotypic antibody (designated B7) was chosen for further characterization by a series of experiments. We first demonstrated that B7 behaved as a typical $Ab2{\beta}$ based on a series of enzyme-linked immunosorbent assays. Subsequently, the results of a competitive receptor-binding assay confirmed that B7 could specifically bind to the prolactin receptor (PRLR) expressed on target cells. Finally, we examined its biological activities in CHO-PRLR and Nb2 cells and observed that B7 could activate Janus kinase 2-signal transducer and activator of transcription signalling in CHO-PRLR and Nb2 cells and induce BaF3 proliferation. The present study suggests that i) B7 can serve as a PRLR agonist or PRL mimic and has potential applications in regulating mammary gland development, milk production and maintenance of lactation in domestic animals and ii) B7 may be a biological reagent that can be used to explore the mechanism of PRLR-mediated intracellular signalling.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.10
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• pp.1291-1298
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• 2010

The aim of this research was to investigate the dynamic changes of the level of total prolactin receptor (PRLR) mRNA and the short form prolactin receptor (S-PRLR) mRNA in skin of cashmere goats from the initiation of cashmere fibre growth to active growth. Eighteen half-sib wethers were allocated randomly to two groups. Melatonin implants were used in order to initiate growth of cashmere fibre before the normal time and reduce blood plasma prolactin (PRL) concentration. Real-time reverse transcription quantitative polymerase chain reaction (real-time PCR) was used to determine PRLR mRNA expression levels of skin from June to November. The results showed that, in Chinese Inner Mongolia cashmere goats, there were seasonal variations in expression of total PRLR mRNA in skin with levels decreasing from June to October. Synchronously, the cashmere fibre growth rate gradually increased during this period, but the expression levels of S-PRLR mRNA did not decrease along with seasonal variation from initiation to active growth of cashmere fibre. These results suggest that expression levels of S- PRLR mRNA might be involved in the process of cashmere growth. It was also possible that the change of alternative splicing of PRLR occurred in the skin of cashmere goats from proanagen to anagen.