[Androgen receptors in the rat submandibular salivary gland. Release of dihydrotestosterone (DHT) binding protein from androgen binding protein in the cytosol].
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Biomedical subjects
Publications and source records attributed to S Koshika.
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The present investigation deals with the changing profile of testosterone (T) and 5 alpha-dihydrotestosterone (DHT) concentrations in the rat submandibular gland (SMG) with age. T and DHT concentrations in SMG from male and female Wistar Rats 0 to 10 weeks of age were measured by a specific radioimmunoassay. T and DHT in male and female SMG showed lower values until 3 weeks (4.5 +/- 1.5 ng/g). However, at 4 weeks of age, T levels greatly increased, revealing 15.1 +/- 6.3 ng/g for males and 18.4 +/- 6.6 ng/g for females. And thereafter from 5 to 10 weeks of age, T concentrations in SMG were decreased to 3--5 ng/g. On the other hand, from 5 to 10 weeks of age, DHT concentrations in both males and females had a tendency to be accumulated, indicating approximately 1.5--3 times higher than T. It can be reasonably concluded that DHT began to be accumulated in SMG at the period of 4 to 5 weeks of age. Furthermore, it is suggested that the rat SMG demands androgen from approximately 4 weeks of age for growth and function.
SPARC is known to be important in development and tissue remodelling. Here, we examined the effects of SPARC (secreted protein, acidic and rich in cysteine; osteonectin) derived from a rat osteosarcoma cell line on migration of renal cell carcinoma (RCC) by a Boyden chamber assay. YCR RCC cells migrated through type IV collagen-coated filters without stimuli (basal level). SPARC in the lower compartment stimulated chemotactic activity to 120% of the basal level, whereas premixing of YCR with purified SPARC before inoculation reduced their migration to 72% of the basal level. Furthermore, SPARC mixed with type IV collagen more efficiently stimulated their migration in a concentration-dependent manner (up to 170% of the basal level). This suggests that SPARC bound to type IV collagen plays a role in tumor invasion.