Effect of Reserpine on Mammary Gland Involution, and on Other Organs in the Rat

Abstract

Two groups of 8 lactating rats received 50 ug and 100 ug of reserpine respectively for 9 days after removal of the litter on 4th day of lactation. A 3d group of 8 animals which re-ceived saline injections served as a control. Histological examination of the mammary glands at the end of this period revealed that reserpine administration caused a marked inhibition of mammary in-volution, this being particularly pronounced at the higher dose level. Reserpine also caused a pronounced decrease in food intake and a considerable loss in body weight at the higher dose level. Both levels of reserpine administration resulted in a significant increase in adrenal weight and a concomitant decrease in thymus weight. Uterine weight was also reduced but ovarian and thyroid weights were unaffected. Histological examination of vaginae and uteri revealed that whereas all reserpine treated animals showed evidence of LTH (leutotropic hormone) release (vaginal mucification), several of the untreated animals were cycling normally again, their uteri and vaginae exhibiting pro-oestrous or oestrous conditions. These results are discussed in relation to the possible mechanisms by which reserpine may exert its effects.