Androgenic expression in the submandibular gland of zinc-deficient mice

The effects of zinc deficiency were studied in mice submandibular salivary glands (SMG). Zn-restricted mice (Zn-) were maintained from weaning until adult age (60 days) with a powdered diet containing 3 mg Zn²⁺/kg. Pair-fed animals (30 mg Zn²⁺/kg powdered diet) and control animals fed a regular pelleted diet were also used. Total protein content and proteolytic acitivity of SMG did not differ among the groups, but mor-phometric evaluations revealed significant alterations in the nucleus/cytoplasm size ratios, most likely due to an absolute reduction in nuclear volume (control = 122.5 ± 6.4; Zn = 91.6 ± 10.5; pair-fed =125.1 ± 6.8 μm³) paralleled by an increase of the height of the duct epithelium (control = 70.5 ± 3.0; Zn⁻ = 90.5 ± 4.2; pair-fed = 81.7 ± 3.0 μm). The altered food consistency could be responsible for these morphological changes. In order to assess the subcellular distribution of SMG androgen receptors in conditions of chronic Zn deficiency, Zn⁻ animals were mated and the F₁ generation was fed as their dams until the age of 45 days. Cytosolic (in 105, 000 #superna-tants) and nuclear (KCl-extracted) SMG receptors were determined with [³H]R1881. The Zn⁻ animals had reduced nu-clear/cytosolic ratios of androgen receptors (control = 0.62; Zn⁻ = 0.14), as an indication that chronically deficient Zn intake determines a sort of destabilization of the interactions of androgen-receptor complexes with target cell nucleus.