LOCALIZATION OF MESSENGER-RNAS OF 2 ANDROGEN-DEPENDENT PROTEINS, SMR1AND SMR2, BY IN-SITU HYBRIDIZATION REVEALS SEXUAL DIFFERENCES IN ACINAR-CELLS OF RAT SUBMANDIBULAR-GLAND

Androgen-dependent sexual differences in the granular convoluted tubul es of mouse and rat submandibular glands (SMG) have been extensively r eported. We studied two major androgen-dependent mRNAs of the rat SMG encoding proteins named SMR1 and SMR2. To determine which cell type in the SMG is responsible for synthesis of these mRNAs, we performed in situ hybridization with digoxigenin-labeled RNA probes coupled with al kaline phosphatase detection. We show that SMR1 and SMR2 mRNAs are syn thesized in the acinar cells of the SMG. A deaf difference in SMR1 and SMR2 mRNA levels in male and female is demonstrated. During the cours e of this study we also confirmed the acinar localization of mRNAs enc oding the glutamine/glutamic acid-rich proteins (GRP) of rat SMG. Our data are the first clear evidence of androgen-dependent sexual differe nces in acinar cells of rat submandibular gland.