CHANGES IN BLOOD FLOW AND VASCULAR PERMEABILITY OF THE TESTIS, EPIDIDYMIS AND ACCESSORY REPRODUCTIVE ORGANS OF THE RAT AFTER THE ADMINISTRATION OF CADMIUM CHLORIDE

Abstract

SUMMARY: The effect of s.c. injections of cadmium chloride (3 μmole/100 g. body wt.) on the blood flow and vascular permeability of the testis, epididymis and accessory reproductive organs of rats has been examined. Sapirstein's indicator fractionation technique was used to measure blood flow with [¹³¹I]iodoantipyrine and [⁸⁶Rb]-rubidium chloride. A rubidium-rejecting compartment was found in the testis similar to, but smaller than, that in the brain and pineal body. Testicular blood flow started to decrease within 3 hr. of giving cadmium (Cd) and by 12 hr. was only 2–9 % of the control values; it then started to recover but after 14 days it was still only 31 % of the control values. Apart from a small reduction of blood flow to the first part of the head of the epididymis 6 hr. after Cd administration, blood flow was not strikingly reduced in any part of the epididymis by Cd treatment. However, blood flow to all parts of the epididymis had increased markedly when examined 7 days after giving Cd; this was most evident in the first part of the head of the epididymis. Blood flow through the accessory reproductive organs was reduced within 6 hr. of Cd injection. Blood flow in the seminal vesicles returned to normal between 1 and 14 days after treatment but blood flow in the prostate gland did not recover. The movement of albumin from intravascular to extravascular compartments was used as an index of vascular permeability. This index increased in the testis in the period 1–6 hr. after Cd administration and the change occasionally occurred before blood flow decreased. A similar increase was seen in the first part of the head of the epididymis 3–6 hr. after Cd, but no change was seen in the rest of the epididymis. The evidence suggests that Cd acts by damaging the endothelium of the capillaries in the testis leading to prolonged stoppage of blood flow which would lead to hypoxia in the spermiogenic epithelium.