EFFECTS OF GROWTH-HORMONE AND PROLACTIN ON TESTICULAR MACROPHAGES IN LONG-TERM HYPOPHYSECTOMIZED RATS

Long-term hypophysectomized (LTHX) rats were treated for 1 week with g rowth hormone (rGH, 600 mu g/kg body wt.), prolactin (rPRL, 600 mu g/k g body wt.), combined rCH/rPRL or vehicle, to study the effects of the se hormones on testicular macrophages. Growth hormone and, to a lesser extent, prolactin significantly increased the number and size of test icular macrophages. The in vivo phagocytic capacity of testicular macr ophages was tested by their ability to clear the testicular interstiti um of dead Leydig cells after treatment with the specific cytotoxic re agent ethylene dimethane sulphonate (EDS). In vehicle- or rPRL-treated rats, abundant EDS-killed Leydig cells (about 50% of the pre-existent population) remained in the testicular interstitium 72 h after EDS tr eatment, whereas clearance of the testicular interstitium of dead Leyd ig cells was largely achieved in rGH- or rGH/rPRL-treated rats. These results indicate that growth hormone and prolactin have stimulatory ef fects on testicular macrophages in LTHX rats.