Progesterone receptors in estrogen-induced fibromatosis of guinea pigs

Expression and intracellular localization of progesterone receptors in cultured human gingival fibroblasts

OBJECTIVE

The aim of this immunocytochemical study was to characterize the expression and distribution of the progesterone receptor (PR) and estrogen receptor (ER) in gingival fibroblasts using culture cells derived from people at various ages.

BACKGROUND

The reaction of female hormones is tissue or cell specific, and receptor availability in the cell is one of the major causes for the different reactions. Gingiva is a target tissue for female hormones; however, the characteristics of PR and ER in both the fibroblasts and the other component cells remain largely unknown.

MATERIALS

Gingival tissue was obtained from six people at various ages and culture fibroblasts were established. At least three passages of each cell line were strained for PR and ER with monoclonal antibodies (Clone 1A6, Clone 1D5, respectively).

RESULTS

PR positive cells were detected in all six cell lines through early passages to late ones, but ER were only observed in two of six samples with faint reactions. The staining intensity for PR was greater than for ER, but less than that shown in the MCF-7 breast cancer cells, positive control. In every positive control test, ER reactivity was equal to or higher than that of PR. During the interphase, significantly fewer positive fibroblasts occurred compared with negative fibroblasts, and positive nuclei were even fewer. Meanwhile, most of the mitotic cells were PR positive, showing intense localization around chromosomes and on microtubules. These findings suggest that gingival fibroblasts are fundamentally capable of expressing PR and transmit the signal to target genes.

CONCLUSIONS

The present study may conclude that in either gender or at any age, gingival fibroblasts express PR rather low in level and do not necessarily localize PR in a nuclear dominant fashion, which is an essential feature for reproductive organ cells. The poor ER reactivity shown in the gingival fibroblasts was discussed in view of the receptor subtype.

Successful treatment of retractile mesenteritis with oral progesterone

Retractile mesenteritis is a rare inflammatory mesenteric disorder that involves the intestine secondarily. The natural history of this process is diverse, but most patients require some empiric therapeutic measures. Up to now, pharmacological therapy has included corticosteroids, colchicine, and immunosuppressive drugs. Although these drugs are successful in most patients, some have been refractory to these therapies and, in others, the beneficial effects were counterbalanced by adverse reactions. Many patients require surgery, but most have poor results. This report describes a 42-year-old man with histologically proven retractile mesenteritis refractory to surgical intervention who had a good response to oral progesterone (10 mg/day for 6 months) with complete disappearance of tumor mass and clinical symptoms. No adverse effects were detected. Current knowledge about the mechanism by which progesterone affects fibrogenesis is scanty. It seems likely that progesterone down-regulates proliferation and metabolism of fibroblasts and fibrogenesis.