ACINAR-CELLS ARE TARGET-CELLS FOR ANDROGENS IN MOUSE SUBMANDIBULAR GLANDS

The variable coding sequence (VCS) multigene family encodes diverse sa livary proteins, such as the SMR1 prohormone and the PR-VB1 proline-ri ch protein in the rat. In situ hybridization was used to study the cel l-specific expression of two new mouse VCS genes, Vcs1 and Vcs2. We sh ow that the Vcs1 transcripts, which code for a proline-rich protein, M SG1, are highly abundant in male and female parotid glands, in which t hey are specifically detected in acinar cells. No expression was seen in the submandibular or sublingual glands. In contrast, Vcs2 transcrip ts were found only in the acinar cells of the submandibular glands (SM Gs) of male mice, in which they are expressed in response to androgens . Expression was found to be heterogeneous within acinar structures. N o Vcs2 transcripts were detected in the SMGs of females or castrated m ales by Northern blot, RNase protection, or in situ hybridization. And rogen administration to females or castrated males induced expression at a level comparable to that of intact males. The Vcs2 gene is the fi rst example of a mouse androgen-regulated gene that is expressed in SM G acinar cells. This result, in addition to our previous observation o n SMR1 expression in rats, demonstrates that both acinar cells and gra nular convoluted tubule (GCT) cells are target cells for androgen acti on in rodent SMG.