Regulatory Effects of Dopamine, Oxytocin, and Thyrotropin- Releasing Hormone on the Release of Prolactin Variants From the Adenohypophysis of Lactating Rats
International Journal of Endocrinology and Metabolism: 9 (3); 382-390 Article Type: Original Article
February 9, 2011
June 20, 2011
A. Regulatory Effects of Dopamine, Oxytocin, and Thyrotropin- Releasing Hormone on the Release of Prolactin Variants From the Adenohypophysis of Lactating Rats,
Int J Endocrinol Metab.
Online ahead of Print
Background: Previous studies used western blotting to show that prolactin (PRL) released from the adenohypophysis (AP) of lactating rats in vitro contains size variants from 7–14 kDa to 70–97 kDa. These variants when eluted from sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels and incubated with AP lactotrophs from male rats and rats in other conditions, promoted the selective stimulation and/or inhibition of the in vitro release of PRL variants. Objectives: In the present study, we determined the regulatory effects of dopamine (DA), thyrotropin-releasing hormone (TRH), and oxytocin (OT) on release of PRL variants from AP lactotrophs. Materials and Methods: Primary cultures of lactotrophs from lactating rats, which were non-suckled (NS) for 6 h or suckled (S) for 15 min after NS, were incubated with PRL variants that were electroeluted from SDS-PAGE gels along with different doses of DA (0.5, 1.0, 1.5 µM), TRH (0.1, 1.0, 10 µM), or OT (0.1, 1.0, 10 µM). The secretion of PRL from the lactotrophs was determined by enzyme-linked immunosorbant assay. Results: The results showed stimulatory and/or inhibitory effects of DA, TRH, and OT on the release of PRL variants from AP lactotrophs both by the presence of PRL variants. Conclusions: These results indicate that PRL variants are released from AP lactotrophs, and, in concert with hypothalamic hormones, they regulate the release of PRL from lactating rat APs.
Implication for health policy/practice/research/medical education: PRL secretion exerted by variants of the PRL in presence of hypothalamic hormones.
Please cite this paper as: Mena F, Navarro N, Castilla A. Regulatory Effects of Dopamine, Oxytocin, and Thyrotropin-Releasing Hormone on the Release of Prolactin Variants From the Adenohypophysis of Lactating Rat. Int J Endocrinol Metab. 2011;9(3):382-90. DOI: 10.5812/Kowsar.1726913X.3179
Copyright © 2011 Kowsar M. P. Co. All rights reserved.
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