Interaction of prolactin and testosterone in the human prostate

Farnsworth, Wells E.; Slaunwhite, W. Roy; Sharma, Manisha; Oseko, F; Brown, James R.; Gonder, Maurice J.; Cartagena, Rubin

doi:10.1007/bf00256681

Cited by 44 publications

(18 citation statements)

References 24 publications

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“…PRL has emerged as the pituitary hormone most likely to account for prostate gland evolution [35], The proliferative effects of PRL are closely associated with androgens. Indeed, PRL can act indirectly on the prostate by altering androgen biosynthe sis at the testis [ 14], or directly in synergism with testoster one by an 'increase in androgen nuclear receptors' [10].…”

Section: Discussionmentioning

confidence: 99%

The Lipidosterolic Extract from Serenoa repens Interferes with Prolactin Receptor Signal Transduction

Vacher¹,

Prevarskaya²,

Skryma³

et al. 1995

J Biomed Sci

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The lipidosterolic extract from the saw palmetto Serenoa repens (LSESr) is commonly used for medical treatment of benign prostatic hypertrophia due to its ability to inhibit 5α-reductase which permits the conversion of testosterone to dihydrotestosterone, the active androgen on prostate cell proliferation. However, the complete action mechanism of LSESr is still unknown. Several lines of evidence suggest that, in addition to inhibition of 5a-reductase, it may interfere with the action of prolactin (PRL). We therefore investigated a possible interference of this plant extract with another hormone that controls prostate gland growth, PRL. As the action mechanism of PRL is now fully documented in Chinese hamster ovary cells expressing the PRL receptor, we have conducted our experiments on these cells. In this study, using electrophysio- logical (whole-cell recording and single-channel recording), microspectrofluo- rimetric and biochemical techniques, we show that LSESr (1-30 μ/ml) reduced the basal activity of a K^+ channel and of protein kinase C (PKC) in CHO cells. In addition, pretreatment of the cells with 1-10 μ/ml LSESr for 6-36 h abolished the effects of PRL on [Ca(2+)]i, K^+ conductance and PKC. LSESr may block PRL-induced prostate growth by inhibiting several steps of PRL receptor signal transduction. LSESr may also be useful for diseases implicating PRL.

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Section: Discussionmentioning

confidence: 99%

The Lipidosterolic Extract from Serenoa repens Interferes with Prolactin Receptor Signal Transduction

Vacher¹,

Prevarskaya²,

Skryma³

et al. 1995

J Biomed Sci

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“…Farnsworth, Slaunwhite, Sharma, Oseko, Brown, Gonder & Cartagena (1981) have shown that the uptake of radiolabelled testosterone by benign prostatic hyperplasia (BPH) was markedly increased by the addition of the prolactin but the existence of specific prolactin-binding sites is controversial (Keenan, Kemp, Ramsey, Garrison, Pearse & Hodges, 1979;Blankenstein, Bolt-De Vries & Schröder, 1982). Recent investigations using an immunocytochemical staining technique have, however, indicated the presence of a prolactin-like molecule in the human prostate gland (Harper, Sibley, Peeling & Griffiths, 1981).…”

Section: Introductionmentioning

confidence: 97%

Characterization of the prolactin receptor in human prostate

Leake¹,

Chisholm²,

Habib³

1983

Journal of Endocrinology

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The uptake of 125I-labelled human prolactin by subcellular fractions obtained from the human hyperplastic prostate was investigated and the specific binding sites were characterized. The binding was both time- and temperature-dependent with maximum specific uptake achieved after incubation for 20 h at 4 degrees C (dissociation constant = 2.4 x 10(-10) mol/l). The present studies also indicate that the bulk of the specific prolactin binding was confined to the 105 000 and 15 000 g membrane fractions whilst the cytosol and nuclear pellet exhibited a lower capacity for the peptide hormone. Attempts to optimize the binding revealed that pretreatment of the subcellular fractions with 4 mol MgCl2/l quadrupled the binding sites; a similar effect was produced after pretreatment with dextran-coated charcoal, but the changes were less pronounced. Furthermore, our studies suggest that the binding was specific for the human prolactin, with other hormones such as ovine prolactin, human LH, human FSH and human GH showing little or no competition. The addition of magnesium and copper ions to the incubation medium also markedly increased the specific binding, whereas calcium, manganese and EDTA inhibited the prolactin uptake. Freezing and storage of tissue at -70 degrees C did not greatly affect the binding sites. The results suggest that we are clearly dealing with a specific prolactin-binding protein.

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“…Prolactin has been implicated in the pathogenesis of prostate cancer [18][19][20][21][22], but there is no evidence suggesting a direct effect of PRL on prostate cancer cells in vivo. Bartsch et al [23,24] observed higher than normal PRL levels in 15-20% of subjects with prostatic cancer.…”

Section: Introductionmentioning

confidence: 99%

Prolactin and luteinizing hormone‐releasing hormone receptors in human benign prostatic hyperplasia and prostate cancer

Kádár¹,

Ben-David

Pontes

et al. 1988

The Prostate

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Using a sensitive micromethod for the determination of prolactin (PRL) binding sites based on 125I-human PRL ligand, PRL receptor levels in specimens of benign prostatic hyperplasia (BPH) and human prostate cancer were estimated by the one-point assay system. Ten of 19 BPH specimens (53%), showed significant PRL binding, four being in the 9-12 fmol/mg range. All ten of these cases had an histological diagnosis of nodular glandular hyperplasia. Of ten adenocarcinomas examined, four samples (40%) exhibited positive PRL binding, the highest receptor levels being 10.2 fmol/mg protein. To characterize the receptors from BPH membranes, samples were then separately pooled according to the results obtained in one-point assays. In the PRL-negative pool no displacement could be detected. In the PRL-positive pool, the Scatchard analysis revealed one class of receptors with an average affinity Kd = 1.1 X 10(-9) M and capacity Bmax = 287 fmol/mg protein. In the prostate cancer specimens, luteinizing hormone-releasing hormone receptors with a high affinity and a low capacity were also found. The results indicate the presence of prolactin receptors in prostate cancer and in BPH. The clinical implications of such findings are not clear, but it is possible that a certain proportion of BPH and prostate cancers might be in part PRL dependent. Further studies are necessary to ascertain this hypothesis in an attempt to improve the treatment of BPH and prostate cancer.

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Interaction of prolactin and testosterone in the human prostate

Cited by 44 publications

References 24 publications

The Lipidosterolic Extract from Serenoa repens Interferes with Prolactin Receptor Signal Transduction

The Lipidosterolic Extract from Serenoa repens Interferes with Prolactin Receptor Signal Transduction

Characterization of the prolactin receptor in human prostate

Prolactin and luteinizing hormone‐releasing hormone receptors in human benign prostatic hyperplasia and prostate cancer

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