ANDROGEN-DEPENDENT EXPRESSION OF CYSTATIN-RELATED PROTEIN (CRP) IN THE EXORBITAL LACRIMAL GLAND OF THE RAT

Cystatin-related protein (CRP), also known as 20 (22)-kDa glycoprotein is expressed not only in the ventral prostate, but also in the lacrim al gland of adult male rats. In this study the expression of CRP in an drogen-treated female animals is studied. CRP mRNA is absent in the la crimal gland of untreated adult female rats, but can be induced by and rogens, although this induction is slower than in castrated male rats. Estradiol, progesterone or glucocorticoids have no effect. In testicu lar feminized rats, however, CRP mRNA is not induced in the lacrimal g land by androgens. At the protein level, the presence of CRP in tears of adult male rats is demonstrated. In female animals or castrated mal e animals CRP can be induced by androgens in a dose-dependent way. Her e also the induction is slower in female rats, even during secondary i nduction after previous full stimulation by androgens. These results i ndicate that androgens and a functionally normal androgen receptor are essential for the expression of CRP in the lacrimal gland. The time c ourse of induction depends on the dose of androgens, the previous cont act with androgens, the duration of the androgen-free interval and the sex of the animals.