Interleukin-2 is a potent inhibitor of Leydig cell steroidogenesis.

@article{Guo1990Interleukin2IA,
  title={Interleukin-2 is a potent inhibitor of Leydig cell steroidogenesis.},
  author={H Guo and Jonica Calkins and M. Michael Sigel and T. Lin},
  journal={Endocrinology},
  year={1990},
  volume={127 3},
  pages={
          1234-9
        }
}
Interstitial tissue of the testis consists of Leydig cells, macrophages, lymphocytes, plasma cells, mast cells and fibroblasts. Previously we have reported that interleukin-1 (IL-1) inhibits Leydig cell androgen production. In the present study, the effect of IL-2 was investigated. Leydig cells (10(5) cells/ml) from adult Sprague-Dawley rats were cultured with or without IL-2 for 24 h. After medium changes, human CG (hCG), 8-bromo-cAMP, or forskolin was added with or without IL-2. Cultures were… 
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References

SHOWING 1-10 OF 30 REFERENCES
Interleukin-1 inhibits Leydig cell steroidogenesis in primary culture.
TLDR
It is suggested that IL-1 is a potent modulator of Leydig cell steroidogenesis and decreased testosterone formation may modulate the immune response and contribute to the catabolic changes occurring during infection.
Interleukin-1 inhibits luteinization of porcine granulosa cells in culture.
TLDR
It was shown for the first time that IL-1 can modulate steroidogenic functions of mammalian cells in culture and markedly inhibited the LH-stimulated progesterone production in a dose-dependent manner.
Transforming growth factor-beta inhibits Leydig cell steroidogenesis in primary culture.
Mechanism of the inhibitory action of epidermal growth factor on testicular androgen biosynthesis in vitro.
TLDR
The mechanism whereby EGF inhibits gonadotropin-stimulated production of testosterone by primary cultures of testicular cells was investigated, and the inhibitory effect of EGF upon hCGstimulated testosterone production was detected 12 h after treatment and was associated with increases in cellular protein, but not DNA, content.
Regulation of Leydig cell function in primary culture by inhibin and activin.
TLDR
The results suggest that activin inhibits testosterone formation by the Leydig cells derived from normal mature rats, and inhibin alone has no effect, but reverses the inhibitory action of activation.
Fibroblast growth factor inhibits luteinizing hormone-stimulated androgen production by cultured rat testicular cells.
TLDR
It is suggested that FGF binds to testicular cells and inhibits LH-stimulated testosterone production by inhibiting, at least partially, 17 alpha-hydroxylase enzyme activities.
Immunoregulatory feedback between interleukin-1 and glucocorticoid hormones.
TLDR
The results strongly support the existence of an immunoregulatory feedback circuit in which IL-1 acts as an afferent and glucocorticoid as an efferent hormonal signal in which the pituitary-adrenal axis is stimulated.
Interferon-gamma inhibits steroidogenesis and accumulation of mRNA of the steroidogenic enzymes P450scc and P450c17 in cultured porcine Leydig cells.
TLDR
In addition to possible suppression of cholesterol availability, decreased P450scc and/or P450c 17 activities were also involved in the IFN gamma suppressed steroidogenic capacity of porcine Leydig cells during long-term hCG stimulation.
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