When results of more than ten different studies on
hormone-induced
calcium signals in Sertoli cells are taken together, a wide variety of responses emerges. The reported changes range from increased concentrations, via no response at all, to decreased
calcium concentrations. Minor variations in cell isolation techniques, culture conditions, or techniques for measuring the intracellular
calcium could explain some of these differences. However, erratic variations in response are also observed within research groups under very similar experimental conditions. Such 'negative' findings are mainly reported orally and do not further penetrate the scientific community. As
hormone-dependent
calcium responses evidently may depend very much on the context of the cells,
calcium transients would appear to be unreliable bioassay principles with which to detect the primary actions of FSH and effectors such as
androgens on Sertoli cells. A more important
biological question is whether these sometimes opposed
calcium transients are connected with a particular cellular response. To date there is no evidence for such a tight coupling in Sertoli cells, implying that, at least under in vitro conditions,
calcium signals might even be redundant altogether. Such
calcium variability is probably not unique to Sertoli cells, and the aim of this commentary is to promote an open debate that may help to transform the current state of '
calcium confusion' into a better understanding of the intracellular
calcium language.