TOXICOLOGICAL CONSEQUENCES OF AROCLOR-1254 INGESTION BY FEMALE RHESUS(MACACA-MULATTA) MONKEYS .1B. PREBREEDING PHASE - CLINICAL AND ANALYTICAL LABORATORY FINDINGS

A group of 80 menstruating rhesus (Macaca mulatta) monkeys, with an av erage estimated age of 11.1 +/- 4.1 yr SD were first randomly allocate d to four similar test rooms (20 monkeys/room), and then randomly allo cated to one of five dose groups (four females/dose group/room). Each day, the monkeys self-ingested capsules containing doses of 0, 5, 20, 40 or 80 mu g Aroclor 1254/kg body weight. After 25 months of daily do sing, approximately 90% of the treated females attained a qualitative pharmacokinetic steady state with respect to the concentration of poly chlorinated biphenyl (PCB) in their adipose tissue. Subsequently, oest rogen and progesterone concentrations in serum were determined for one complete oestrous cycle and various immunological tests were conducte d, while the monkeys continued to receive their daily dose of PCB. Dur ing the prebreeding phase of the study, blood for clinical and analyti cal monitoring including haematology, serum biochemistry, serum hydroc ortisone, serum proteins (alpha 1, alpha 2, beta and gamma-globulins), serum immunoglobulins (A, G and M) and thyroid variables (thyroxine/t riiodothyronine (T-3) uptake ratio, percentage T-3 uptake and free thy roxine index), were obtained monthly,:as were specimens to ascertain t he concentration of PCB in the blood, adipose tissue and faeces. Major findings among treated monkeys included the following: changes in hae matology (decreased erythrocyte count, haematocrit, reticulocyte count , and mean platelet volume), serum biochemistry (decreased cholesterol and total bilirubin), immunotoxicity (decreased antibody production t o sheep red brood cells and alterations in the percentage of T helper and T suppressor cells) and pathology (the number of regions of sebace ous gland lobules per unit of histological length was significantly re duced). These effects were observed at PCB doses lower than those prev iously reported for non-human primates: