A. Wahab-wahlgren et al., Constitutive production of interleukin-1 alpha mRNA and protein in the developing rat testis, INT J ANDR, 23(6), 2000, pp. 360-365
Interleukin-1 (IL-1), a multifunctional cytokine produced mainly by activat
ed macrophages, is also produced in the intact testis. Rat testicular IL-1
was found to be identical to IL-1 alpha, judged by immunoneutralization of
the bioactive protein and sequence comparison of cloned rat testicular and
macrophage pro-IL-1 alpha cDNA. Testicular IL-1 alpha mRNA was first demons
trated on postnatal day 15, and the corresponding bioactive protein from da
y 20. IL-1 alpha mRNA was still low on day 20, but then increased rapidly i
n parallel with the bioactive protein to establish a plateau level from day
25. In adult testes, IL-1 alpha mRNA and immunoreactive protein were low i
n stage VII of the seminiferous epithelial cycle, whereas other stages show
ed a clearly detectable expression. In the adult testis, the concentration
of IL-1 alpha was 75 pg/mg testicular protein (approximately 200 pM). In co
nclusion, production of testicular IL-1 alpha is developmentally and stage-
dependently regulated, probably at the transcriptional level, emphasizing a
n important paracrine role in testicular function.