Effects of Castration, Testosterone, Estradiol, and Prolactin on Specific Prolactin-Binding Activity in Ventral Prostate of Male Rats

Kledzik, G. S.; Marshall, Stephen; Campbell, Graeme; Gelato, Marie C.

doi:10.1210/endo-98-2-373

Cited by 65 publications

(14 citation statements)

References 17 publications

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“…The mechanism of this interaction is, however, currently being investigated. The apparent lack of effects of prolactin withdrawal and addition on the levels of its own membrane receptor supports previous observations indicating that this receptor is relatively resistant to up or down regulation by prolactin in this gland (Kledzik, Marshall, Campbell, Gelato & Meites, 1976; Barkey, Shani & Barzilai, 1979).…”

Section: Discussionsupporting

confidence: 87%

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

Rui¹,

Haug²,

Mevåg³

et al. 1985

Reproduction

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The effects of a single injection of ovine prolactin on prostatic function were monitored in intact, intact androgenized and castrated-androgenized rats rendered hypoprolactinaemic after 7 days of treatment with a potent dopamine agonist, lisuride. Hypoprolactinaemia was associated with reductions in ventral prostate weight, polyamine levels, lateral lobe zinc and the concentration of the ventral prostate protein prostatein, but an elevation in the level of cytosolic oestradiol binding. Whether these differences attained statistical significance depended on whether the animals were intact, intact-androgenized or castrated-androgenized. With the exception of ventral prostate weight and lateral lobe zinc concentrations, a single injection of prolactin restored or reversed these changes towards control levels within 12 h, which could not be explained by an indirect effect of the hormone on adrenal or testicular function. No effects of lisuride or prolactin were observed with regard to the content of fructose in the coagulating gland or in the degree of prolactin binding to prostatic membranes.

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Section: Discussionsupporting

confidence: 87%

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

Rui¹,

Haug²,

Mevåg³

et al. 1985

Reproduction

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“…Inhibitors of prolactin release also decrease the concentration of esterified cholesterol in the testes (Bartke, 1974; for review see Horrobin, 1975). Binding sites for prolactin have already been reported in membrane preparations of the testis, epididymis, prostate and seminal vesicle (Frantz, Maclndoe & Turkington, 1974;Aragona & Friesen, 1975;Hanlin «fe Yount, 1975;Kledzik, Marshall, Campbell, Gelato & Meites, 1976), and we have presented preliminary reports of prolactin binding to seminal vesicle, prostate and testicular tissue (Barkey, Shani, Amit & Barzilai, 1976; Utilizing the biologically active (Frantz «fe Turkington, 1972) 125I-Iabelled ovine prolactin produced by lactoperoxidase radio-iodination, we decided to investigate further the nature of prolactin binding activity, especially to the seminal vesicles and prostate glands of the rat, and to study its kinetics as well as its specificity. Affinity constants and binding capacities of seminal vesicle and prostate homogenates were determined by Scatchard analysis (Scatchard, 1949).…”

mentioning

confidence: 92%

Specific Binding of Prolactin to Seminal Vesicle, Prostate and Testicular Homogenates of Immature, Mature and Aged Rats

Barkey¹,

Shani²,

Amit³

et al. 1977

Journal of Endocrinology

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Ovine prolactin was iodinated by the lactoperoxidase method and purified by gel filtration on Sephadex G-100. The binding ability of the labelled hormone was determined, by incubation with liver homogenate from rabbits in late pregnancy, to be 8-8% total binding/mg protein, of which 86% was specific. The fraction of 125I-labelled ovine prolactin which bound most strongly was subsequently used to study its binding to rat seminal vesicle, prostate and testicular homogenates. The total binding to the seminal vesicle homogenate taken from mature (80-day-old) rats was the highest (11-69%/mg protein), but the greatest degree of binding specificity (82-6%) was to immature (30-day-old) rat prostate. Both total and specific binding to rat testicular homogenate were consistently very low. The binding specificity was demonstrated by displacement studies: while ovine prolactin caused displacement of specific binding, human chorionic gonadotropin, rat thyrotropin and human follicle-stimulating hormone did not cause any significant displacement of bound 125I-labelled ovine prolactin. Affinity constants (Ka) and binding capacities for the seminal vesicle and prostate homogenates were determined by Scatchard analysis and the effect of age on these parameters was studied. There was no difference in Ka between the aged (220-day-old), immature and mature rat tissue homogenates; however, a significant fall in binding capacity was observed in the mature rat prostate, and a further fall in the aged rat prostate. No such change was observed in the binding capacity of the seminal vesicle, as estimated by Scatchard analysis, although total and specific binding to the mature homogenates was higher than that of the other age groups.

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“…In contrast to the radiometric methods on cell-free homogenates used by others (1,14,16), the immunoperoxidase approach offers the advantage of visualizing the actual location of hormone binding in relation to cell and tissue structure. This is particularly important in heterogeneous tissues such as pros tatic cancer.…”

Section: Discussionmentioning

confidence: 99%

“…Several laboratories have recently demonstrated the binding of [12SI]-iodoprolactin to crude membrane-rich particulate fractions of normal rat prostate gland (1,14,16). As an alternative to studies using cell-free homogenates and radiolabelled hormones, we have demonstrated intracellular prolactin-binding sites (IPBS) in epithelial cells of rat ventral and dorsolateral prostate glands using immunohistochemistry (27,28).…”

Section: Introductionmentioning

confidence: 94%

Immunohistochemical Localization of Prolactin-Binding Sites in R3327 Rat Prostatic Cancer Cells

Witorsch¹

1979

Horm Res

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Light microscope immunohistochemistry was used to test for and to localize prolactin-binding sites in the transplantable R3327 rat prostatic carcinoma. Fixed tissue sections of the tumor were first incubated with vehicle or varying concentrations of highly purified NIAMDD rat prolactin and then exposed to an immunoperoxidase staining sequence. Prolactin produced dose-related, immunospecific, staining in the cytoplasm of some neoplastic cells, indicative of intracellular prolactin-binding sites (IPBS). While cells with IPBS have been demonstrated in both differentiated and undifferentiated regions of this cancer, a role for prolactin in prostatic neoplasia, be it stimulatory or inhibitory, remains to be elucidated.

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Effects of Castration, Testosterone, Estradiol, and Prolactin on Specific Prolactin-Binding Activity in Ventral Prostate of Male Rats

Cited by 65 publications

References 17 publications

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

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

Specific Binding of Prolactin to Seminal Vesicle, Prostate and Testicular Homogenates of Immature, Mature and Aged Rats

Immunohistochemical Localization of Prolactin-Binding Sites in R3327 Rat Prostatic Cancer Cells

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