| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1987: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1986: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
There are several lines of evidence suggesting that a certain local tissue facor such as prowth factor, in addition to androgens, is involved in the prostate growth. We found that the prostate contained two types of growth factor capable of stimulating DNA synthesis in BALB/c3T3 fibroblasts. They were divided into low affinity (LoA) type and high affinity (HiA) type by a different affinity for heparin-Sepharose.
Rat prostate growth factor (rPGF) About 80% of rPGF in normal dorsolateral prostate (DLP was LoA type, whereas more than 80% in the Dunning tumor, a prostatic carcinoma originated in the DLP, was HiA type. HiA-rPGF purified from the Dunning tumor had a molecular weight of about 19,000 and pI of about 3.8. It was stimulated by dithiothreitol (DTT),but inactivated by heat- and acid-treatments, indicating that HiA type in the Dunning tumor is a member of acidic FGF (fibroblast growth factor). LoA-rPGF purified from the DLP had a mol. wt. of about 14,000 and pI of about 4.5. It was stable against heat- and acid-treatments, but not against DTT. Immunological data indicate that it is not EGF.
Human prostatic growth factor (hPGF) of the two types of hPGF, LoA type in normal prostate was not major. HiA type was major in all the specimens of normal, benign hypertrophic and cancerous prostates. HiA type was found to be most abundant in BPH tissues. HiA-hPGF purified from BPH tissues had a mol. wt. of about 12,000 and pI of about 10.5. It was stable against DTT, but not heat- and acid-treatments. These indicate that HiA -hPGF in BPH tissues is a member of basic FGF. We also found that prostatic cancer contains a growth factor specific for MC3T3-E1 osteoblasts. This might be a candidate for the prostate osteoblastic factor. Although there are many uncertainties in the relation between prostatic growth factors and androgens, these growth factors are the most probable cause of abnormal growth of the prostate.
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