Characterization of nontransformed and transformed androgen receptor from rat submandibular gland.

Rat submandibular gland cytosol contained androgen receptor which had a single class of specific binding and an apparent dissociation constant of (1.1-1.2) X 10(-9) M. The process of transformation was investigated by a slightly modified minicolumn method in which the transformed receptor complexes were separated from the nontransformed receptor and meroreceptor. 10 mM ATP or pyrophosphate at 0 degrees C induced transformation of androgen receptor as did heat or salt treatment. 20 mM of sodium molybdate completely inhibited transformation that resulted from ATP, heat or salt treatment. The nontransformed androgen receptor complexes sedimented at 8 S and eluted at 250-260 mM KCl from DEAE-Sephacel, and its molecular weight was found to be 220 000 on Sephacryl S300 gel chromatography. On the other hand, the transformed androgen receptor complexes sedimented at 4.1-4.3 S (ATP or KCl treatment) or 3.5-3.8 S (heat treatment) and eluted at 60-80 mM KCl from DEAE-Sephacel. The molecular weight of the transformed androgen receptor complexes was 80 000-85 000 (ATP or KCl treatment) or 70 000-80 000 (heat treatment). These results suggest that the transformation of androgen-receptor complexes from rat submandibular gland was induced by the subunit dissociation and that salt bridges may be involved in the subunit interaction.

Effect of isoprenaline on salivary gland lipids of rats fed a choline-deficient diet.

Male adult rats were fed choline deficient and a choline-supplemented diet for 3 weeks. Half the rats from each group were injected with isoprenaline (16 mg/kg body weight) and the remainder with saline. After 2 and 8 hours, rats were sacrificed, their submandibular salivary glands were disected out, and extracted for lipids. The fatty acid composition of total lipids and some neutral and phospholipid fractions were determined. Isoprenaline administration resulted in a slightly higher level of oleic acid in SMSG of rats fed choline-deficient but not the control diet. There was an increase in the free fatty acid (FFA) concentrations of the gland after 2 hours of isoprenaline treatment in rats fed the control diet; no such increase was observed in the choline-deficient group. The fatty acid composition of FFA fraction was also slightly changed as a result of isoprenaline treatment, but only in the choline-deficient group. The fatty acid composition of triglyceride (TG), phosphatidyl choline (PC), and phosphatidyl ethanolamine (PE) fractions was not changed.

Potentiation of the NGF-mediated nerve fiber outgrowth by ginsenoside Rb1 in organ cultures of chicken dorsal root ganglia.

The fiber outgrowth induced by ACh, dibutyryl cyclic AMP and dibutyryl cyclic GMP in explanted chick embryonic dorsal root ganglia differed distinctly from that be nerve growth factor (NGF) and submandibular gland extract of adult male mice. Ginsenoside Rb1 potentiated the effects of NGF and submandibular extract at concentrations of 3 and 30 muM, but did not potentiate the effects of ACh, dibutyryl cyclic AMP and dibutyryl cyclic GMP. NGF-antibody inhibited the effects of NGF, but not the effects of ACh, dibutyryl cyclic AMP and dibutyryl cyclic GMP, Concanavalin A and KCL did not promote fiber outgrowth.