Transforming growth factor beta 2 is able to modify mRNA levels and release of luteinizing hormone-releasing hormone in a immortalized hypothalamic cell line (GT1-1)

On the basis of our previous observations which indicated that transforming growth factor beta 1 (TG F beta 1) affects the gene expression and the release of luteinizing hormone-releasing hormone (LHRH) in GT1-1 cells, we have presently evaluated whether also TGF beta 2 might be effective on these parameters. The data here reported show that also TGF beta 2 is able to affect LHRH dynamics, and that this action presents a different kinetics than that reported by TGF beta 1. In particular TGF beta 2 is able to facilitate LHRH release and to decrease the mRNA levels of this decapeptide. The present data have also shown that, GT1-1 cells express the messengers for the two most important receptors of the TGF beta family, namely TGF beta RI and TGF beta RII and consequently represent a target for the action of the different isoforms of TGF beta. Since the two isoforms of TGF beta are produced and released from astrocytes, the present data add new support to the hypothesis that astrocytes participate in the control of LHRH secretion in a paracrine fashion. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.