Cultured human skin fibroblasts: a model for the study of androgen action

Abstract

Human skin may be considered as a target organ for androgens, as are male sex accessory organs, since all events involved in testosterone action have been observed in this tissue. As a corollary, the mechanism of androgen action can be studied in vitro in cultured skin fibroblasts. The advantages of this system are that studies can be performed with intact human cells under carefully controlled conditions, differentiated genetic and biochemical characteristics of the cells are faithfully preserved and the biological material is renewable from a single biopsy specimen. The metabolism of androgens, in particular the 5 alpha-reduction of testosterone to the active metabolite, dihydrotestosterone, the intracellular binding of androgen to its specific receptor protein and its subsequent translocation to the nucleus have been studied in skin fibroblasts. The intracellular androgen receptor content of genital skin fibroblasts is higher than that from nongenital skin sites. In addition, the androgen receptor has been characterized as a specific macromolecule with properties of high affinity and low capacity similar to that of other steroid hormone receptors. The pathophysiology of three genetic mutations which alter normal male sexual development and differentiation has been identified in the human skin fibroblast system. In 5 alpha-reductase deficiency, an autosomal recessive disorder in which dihydrotestosterone formation is impaired, virilization of the Wolffian ducts is normal but the external genitalia and urogenital sinus derivatives are female in character. At least two types of X-linked disorders of the androgen receptor exist such that the actions of both testosterone and dihydrotestosterone are impaired and developmental abnormalities may involve both Wolffian derivatives and the external genitalia as well. These two forms of androgen insensitivity result from either the absence of androgen receptor binding activity (receptor (-) form) or apparently normal androgen receptor binding with absence of an appropriate biological response (receptor (+) form). In addition, studies with human skin fibroblasts may also be of value in defining the cellular mechanisms underlying the broad spectrum of partial defects in virilization. In summary, we have correlated our studies of the molecular mechanism of androgen action in human genital skin fibroblasts with those of other investigators as these studies contribute to our understanding of male sexual development and differentiation.

Familial Incomplete Male Pseudohermaphroditism Associated with Impaired Nuclear Androgen Retention. STUDIES IN CULTURED SKIN FIBROBLASTS

“…The characteristics of the nuclear uptake assay used in this study, which shows -40-50% of the binding sites found in the intact, whole cell, are in accord with published data (11,19). Also, the whole cell assay gives androgen binding characteristics for fibroblasts (15) and the MCF-7 cells that are also in good agreement with the results of others (21). Moreover, the results of the sucrose gradient analysis on nuclear extracts shown in Fig.…”

“…5). In contrast to an easily identifiable peak of radioactivity in the 4S region of the gradient for the nuclear extract of the normal cells that was eliminated by coincubation 20 (20,21) it is unlikely that using a higher salt containing solution to extract the nuclei would have significantly altered the results of the gradient analysis, since the amount of specific total radioactivity incorporated into the nuclei of the patients' cells is so low (Fig. 1 and Table I).…”

Intracellular and nuclear binding of [3H]dihydrotestosterone in cultured genital skin fibroblasts of patients with severe hypospadias.

“…Among the 11 patients studied, 10 had severe hypospadias, in some instances associated with other genital abnormalities. We selected these patients in an attempt to avoid subtle abnormalities of the external genitalia.…”

“…Binding was assessed using (with minor modifications) the methods described by Brown et al (10,11). In brief, after incubation, the medium was removed, and the monolayers were washed three times with 5 ml ice-cold Tris-NaCl buffer (0.9% NaCl, 20 mM Tris-HCl, pH 7.4).…”

Glucocorticoid receptors in human preadipocytes: regional and gender differences

“…Moreover, their presence after prolonged in vitro growth suggests that these are intrinsic differences, rather than differences due to circulating hormones or differing regional influences. The potential stability of the steroid receptor complement of subcultured cells is exemplified by the consistent regional differences in androgen receptor density and androgen responsiveness of subcultured skin fibroblasts (Brown & Migeon 1981).…”