Short-term effects of prolactin on prostatic function in rats with lisuride-induced hypoprolactinaemia

Rui, Hallgeir; Haug, Egil; Mevåg, B.; Thomassen, Yngvar; Purvis, K.

doi:10.1530/jrf.0.0750421

Cited by 11 publications

(7 citation statements)

References 20 publications

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“…The measurements of citric acid, PAP and fructose were carried out as described earlier (Rui et al 1984), and the assays for PGE, polyamines and putrescine have also been reported previously (Rui et al 1985). Protein was determined by the method of Lowry et al (1951).…”

Section: Methodsmentioning

confidence: 99%

Time‐ and temperature‐related alterations in seminal plasma constituents after ejaculation

Rui¹,

Mørkås²,

Purvis³

1986

Int J of Andrology

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The effects of temperature and incubation time were examined on the concentrations of the following seminal plasma constituents in ejaculates from seven healthy volunteers: prostatic acid phosphate (PAP), citric acid, testosterone, prostaglandin E (PGE), fructose, protein, putrescine and the polyamines spermidine and spermine. The results indicated that the majority of glandular products were stable up to 3 h after ejaculation when stored at room temperature, with the exception of the prostatic diamine putrescine, which appeared to undergo rapid metabolism. Prolonged periods of incubation resulted in a gradual reduction in the levels of fructose and a significant increase in the activity of PAP and the levels of spermidine. On the basis of these findings it appears that an evaluation of the functional integrity of the accessory sex glands can be carried out on semen up to 3 h after ejaculation.

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Section: Methodsmentioning

confidence: 99%

Time‐ and temperature‐related alterations in seminal plasma constituents after ejaculation

Rui¹,

Mørkås²,

Purvis³

1986

Int J of Andrology

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“…Prostate secretory function and probasin expression are sensitive to changes in circulating testosterone and PRL (Cunha et al, 1987;Rui et al, 1985). We therefore examined serum levels of these hormones in Stat5a-deficient male mice.…”

Section: Circulating Levels Of Testosterone and Prl Are Normal In Stamentioning

confidence: 99%

“…It remains mechanistically unclear why selective Stat5a deficiency or an associated imbalance in PRL signal transduction would be associated with increased levels of secretory probasin. In fact, PRL generally stimulates differentiation and secretory function of rodent prostates (Costello and Franklin 1994;Rui et al, 1985). Further knowledge of regulatory targets of the Stat5a transcription factor and insight into the role of individual signal transduction pathways downstream of PRL receptors in the prostate may clarify this apparent paradox.…”

Section: Similar Levels Of Local Prl Immunoreactivity Inmentioning

confidence: 99%

Epithelial Defect in Prostates of Stat5a-Null Mice

Nevalainen

Ahonen

Yamashita

et al. 2000

Laboratory Investigation

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SUMMARY:The transcription factor Stat5a critically mediates prolactin (PRL)-induced mammary gland development and lactogenesis. PRL also stimulates growth and differentiation of prostate tissue. Specifically, hyperprolactinemia gives rise to prostate hyperplasia, and prostate size is reduced in PRL-deficient mice. We therefore investigated the importance of Stat5a for prostate development and function by examining Stat5a-null mice. The absence of Stat5a in mice was associated with a distinct prostate morphology characterized by an increased prevalence of local disorganization within acinar epithelium of ventral prostates. Affected acini were typically filled with desquamated, granular epithelial cells that had become embedded in dense, coagulated secretory material. These features were reminiscent of acinar cyst formation and degeneration frequently observed in human benign prostate hyperplasia, however, cystic changes in prostate acini of Stat5a-deficient mice were not associated with increased prostate size or morphologic hallmarks of epithelial hyperplasia. Instead, immunohistochemistry of the prostate-specific secretory marker, probasin, suggested that hypersecretory function of the epithelium could underlie local congestion and cyst formation in prostates of Stat5a-null mice. Serum testosterone and PRL levels were normal in Stat5a knockout mice, but prostate PRL receptor expression was reduced as determined by immunohistochemistry. Expression levels or activation states of other PRL signal transduction proteins, including Stat5b, Stat3, Stat1, ERK1, and ERK2 were not altered. The present study offers the first evidence for a direct role of Stat5a in the maintenance of normal tissue architecture and function of the mouse prostate. (Lab Invest 2000, 80:993-1006.

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“…The lowest dose of o-PRL eliciting an effect was 150 µg/l, which is in the upper range of circulating rodent prolactin under normal conditions (Rui et al 1985). On the other hand, differences in the receptor specificity for the ovine and endogenous hormone and the biological activity of the com¬ mercial preparation should also be considered.…”

Section: Discussionmentioning

confidence: 99%

Further observations on the autoregulation of the prolactin receptor in rat ventral prostate explants

Rui¹,

Brekke²,

Torjesen³

et al. 1987

Acta Endocrinologica

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In confirmation and extension of an earlier preliminary communication, ovine prolactin was found to elevate prolactin binding by approximately 100% in rat ventral prostate explants incubated for 20 h in vitro.A stimulation was observed with low doses of ovine hormone (150 \g=m\g/l ) which, from available data on the relative biological potencies, could be considered equivalent to the upper limit of the physiological range of endogenous rat prolactin. The response was associated with a lag period of 3\p=n-\6h. The effect could be obtained with other lactogenic hormones, including human and rat prolactin and human growth hormone, but not with non-lactogenic hormones such as insulin, hCG, corticosterone, testosterone or oestradiol. The prostaglandin synthesis inhibitor, indomethacin, and the Ca2+-antagonist, verapamil, could not counteract the increase in prolactin binding induced by prolactin treatment, nor could dibutyryl cyclic AMP alone mimic the response. These data suggest that prostaglandins, Ca2+ or cAMP do not mediate the alteration in receptor binding. Furthermore, inhibition of lysosome activity by chloroquine could not alone increase the prolactin binding in the control tissues, suggesting that up-regulation does not simply reflect a protective action of prolactin on receptor degradation. The degree and the direction to which prolactin modulates the concentration of its membrane receptor in its target organs is still a source of controversy. In the rat, evidence has been pres¬ ented for an up-regulation (Dave & Witorsch 1985; Blankenstein et al. 1985), a down-regula¬ tion (Barash et al. 1983), and lack of effect (Kledzik et al. 1976;Amit et al. 1983) in vivo. In a preliminary publication, we recently reported both an apparent up-regulation and a down-regulation of the receptor in prostatic expiants which were dose-dependent (Rui et al. 1986). Such a biphasic response was presented as a possible explanation of the inconsistent findings reported by others. The present study extends these initial observations by examining the specificity and pos¬ sible mechanisms underlying the up-regulatory component of the response. Materials and Methods Preparation of the expiantsAdult male Sprague-Dawley rats (M0llegaard Breeding Centre, Skensved, Denmark), aged 140-160 days, were sacrificed by cervical dislocation under ether anaes¬ thesia. The ventral prostate lobes from each animal were divided into culture dishes (Costar, Ma, USA; 3.9 cm diameter) prefilled with medium (2 ml; Eagle's Minimum Essential,The tissue was minced immediately, and this procedure was then repeated with the ventral lobes of a second animal which were divided into the same culture dishes.The number of culture dishes varied (from two to eight) depending on the experimental design. Each culture dish thus contained prostatic tissue (100-200 mg) from two animals. This procedure was carried out under sterile conditions at room temperature. Sterile water (Gibco Laboratories, Ohio, USA), 5 ml containing peni¬ cillin (107 U/l, streptomycin base (10 g/...

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Short-term effects of prolactin on prostatic function in rats with lisuride-induced hypoprolactinaemia

Cited by 11 publications

References 20 publications

Time‐ and temperature‐related alterations in seminal plasma constituents after ejaculation

Time‐ and temperature‐related alterations in seminal plasma constituents after ejaculation

Epithelial Defect in Prostates of Stat5a-Null Mice

Further observations on the autoregulation of the prolactin receptor in rat ventral prostate explants

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