Browsing by Subject "Prolactin"

Now showing 1 - 4 of 4
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    In vitro modifications in the proliferation
    (Murcia : F. Hernández, 1995) Carretero, J.; Rubio, M.; Navarro, N.; Prieto, P.; Vázquez, R.J.; Sanchez, F.; Vazquez, R.
    In order to establish the correlation between in vitro proliferation rate and morphometric variations of prolactin immunoreactive cells, a morphometric study was carried out in rat pituitary monolayer cultures by means of the double immunocytochemical staining methods employing mouse monoclonal antiproliferative cell nuclear antigen (PCNA) and rabbit anti-prolactin (PRL) as primary antibodies. PCNA was found to be an adequeate marker for proliferation in pituitary monolayer cultures. 48.35+2.78% of the cells present in the culture were in active cell cycle after 3 days of incubation and a similar proportion, 54.93&2.83% was found after 7 days. On the 3rd day, PRL imrnunopositive cells accounted for 15.16*0.21% of the total cellular content in the dishes and 8.68*0.12% of the PCNA immunoreactive cells were also PRL immunopositive cells and, 60.95112.65% of PRL cells stained for PRL and PCNA. On the 7th day, an increase to 32.18f 0.60% of PRL cells was found; the PCNA and PRL cells accounted for 60.32*2.34% of the total PRL cells, and 19.88I1.09% of the PCNA reactive cells stained for PRL. Additionally, the morphometric analysis performed after 3 or 7 days of incubation showed that, while the size of PRL cells remained unmodified, the nuclear area had increased on the 7th day in relation to the 3rd day (pc0.01). These results suggest: 1) PCNA is a valid proliferative marker for pituitary cells in cultures; 2) a very high percentage of the PRL cells was in early proliferation; 3) on the 7th day of incubation, the proliferative rate of PRL cells was very similar to that observed on the 3rd day, suggesting a maintained proliferation for PRL cells at early incubation phases; and 4) the cellular activity, expressed as variations in the nuclear size, was higher on the 7th day than on the 3rd day; in addition, the numerical density of PRL cells increased.
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    Light microscopical morphometry of prolactin secreting adenomas under treatment with dopamine agonists
    (Murcia : F. Hernández, 1987) Hamester, U.; Saeger, W.; Ludecke, D.K.
    In order to study the light microscopical alterations of pituitary tumours under dopamine agonist treatment, three groups of a total of 18 large or small cell chromophobe adenomas were analysed by light microscopical, immunohistological and morphometrical methods. They were all removed by transsphenoidal surgery. 6 of them were treated preoperatively with dopamine agonists, bromocriptine andlor lisuride, for various periods of time. 8 adenomas remained preoperatively untreated. 4 additional untreated tumors were small cell inactive adenomas for comparison. One case was excluded from the final evaluation of the data because it appeared to be a typical non-responder, clinically as well as histologically. Immunohistological positivity for prolactin was to be found in all cases in various degrees. Clinically active adenomas contained many prolactin positive cells, whereas in inactive adenomas only scattered cells were prolactin positive. The morphometric analysis revealed a reduction of the cytoplasmic area in a statistically significant degree in the group of adenomas under treatment, which explains adequately the shrinkage of the entire adenoma and the reduction of prolactin plasma levels. The morphometric data of treated adenomas resembled those of untreated inactive adenomas.
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    lmmunohistochemical localization of prolactin in functioning and regressing corpus luteum of pituitary autotransplanted rats
    (Murcia : F. Hernández, 1986) Martín de las Mulas, J.; Aguilar, E.; Sánchez-Criado, J.E.
    In an attempt to shed light on the intimate mechanism by which prolactin (PRL) switches from supporting corpus luteum (CL) progesterone secretion (P) to promote structural regression of the CL, day 2 (metestrous) autopituitary transplanted (APTr) rats were used. In APTr rats the CL is under the only control of PRL since an almost complete absence of LH and FSH exist. The experimental group was given bromocriptine (CB-154: 0.4 mg/day) on days 12, 13 and 14 of the cycle and 0.25 ml of ethanol from day 15 to day 21. The control group was given CB-154 from day 12 to day 21. Rats were hemiovariectomized on day 12 to assess the morphological characteristics of the active CL. PRL and P were determined by RIA on days 12, 15 and 22. On day 12, both PRL and P levels were higher than 80ng/ml (luteotrophic action of PRL). On day 15, due to treatment with CB- 154, the levels of both hormones had fallen below 7 ng/ml (functional luteolysis). On day 22, PRL levels were again high ( > 50 ng/ml) in the shortly CB-154-treated rats and low ( < 5 ng/ml) in the controls; the P levels were lower than 5 ng/ml in both groups. PRL-induced structural luteolysis in the experimental group (hyperprolactinemic) was assessed by the structural characteristics and by the CL weight loss on day 22 in comparison with that exhibited by control rats. The immunohistochemical staining of both endogenous and total PRL in the lutein cells showed that the internalization of PRL is not modified by the functional state of the CL, nevertheless the intracellular redistribution of the internalized hormone varied in relation with the PRL action on the CL (luteotrophic, day 12vs luteolytic, day 22).These results seem to indicate that intracellular mechanisms rather than receptor content determine CL response to PRL.
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    The effect of somatostatin analog octreotide on diethylstilbestrol-induced prolactin secretion, cell proliferation and vascular changes in the rat anterior pituitary gland
    (Murcia : F. Hernández, 1997) Pawlikowski, M.; Kunert-Radek, J.; Grochal, M.; Zielinski, K.; Kulig, Andrzej
    The effects of diethylstilbestrol (DES) and of long-acting somatostatin analog, octreotide (SMS) on the rat anterior pituitary microvasculature have been studied by means of computer-assisted image analysis. Additionally, the effects of DES and SMS on prolactin secretion and anterior pituitary cell proliferation have been studied, as well. The vascularization was visualized using Selye's method modified by Poely et al. (1964). The prolactin serum levels were estimated by radioimmunoassay. The proliferation indices were assessed using bromodeoxyuridine incorporation assay. As expected, it was found that DES sharply increased serum prolactin levels and enhanced cell proliferation in the anterior pituitary gland. DES also induced changes in parameters of vascularization. Simultaneous treatment of rats with SMS inhibited the DES-induced elevation of prolactin levels and pituitary cell proliferation. It also suppressed some but not al1 DES-induced changes in the anterior pituitary vascularization. These data suggest that the angio-inhibitory activity of SMS might be involved in its anti-tumor action on pituitary adenomas, but not as a sole or principal mechanism.