Cadmium-induced changes in avian renal morphology.

The effects of i.m. administered cadmium on growth rate and nephromorphology were studied in young pullets. The growth rate of pullets treated with 0.6 mg Cd2+/kg at 48-h intervals was severely retarded, reaching only 50% of normal growth by 21 days. Such a decrease in growth rate was prevented when cadmium was given with either ferric or magnesium EDTA chelate. Electron micrographs of kidney tissue from cadmium intoxicated birds revealed massive intracellular disorganisation of proximal tubular cells, showing increased vacuolation and dilated endoplasmic reticulum. Mitochondria were few and swollen with reduced cristae. Some disorganisation was noted in the group treated with MgEDTA in conjunction with cadmium, with normal morphology observed in the group treated with FeEDTA plus cadmium. In general, glomerular morphology of intoxicated pullets appeared normal, except that a 25% increase in thickness of the glomerular basement membrane was evident. No such membrane thickening was observed in any of the chelate treated groups. These findings indicate that both chelates can provide certain levels of protection, in terms of growth rate and morphology, from cadmium intoxication. The possible mechanisms by which chelates offer protection have been discussed, but many questions remain unanswered.

Exercise-induced changes in urinary water and mineral output during the menstrual cycle.

This study monitors changes in urinary excretion of water and minerals before and after exercise in pre-menopausal women and in those using oral contraception. Resting urine flow rate was lower and sodium output significantly higher (p less than 0.02) during the normal post-menstrual phase than during other phases of the cycle. These changes were unrelated to glomerular filtration rate and might impede maximal performance. After exercise an oliguria and hyponatriuresis were most pronounced during the menstrual phase. In addition the resting urinary output of calcium and magnesium were unrelated to normal oestrogenic and progestegenic cyclic surges. Amongst oral contraceptive users, resting excretion of water, minerals and creatinine were all significantly lower than general menstrual cycle values (p less than 0.01) and further reductions in salts and water output occurred with exercise. Basal calcium and magnesium excretion rates were significantly lower than general menstrual cycle values (p less than 0.05). Renal conservation of water and salts for 'pill' takers may affect renal homeostasis. The consequences of mineral retention are unknown.

Cadmium-induced changes in renal hemodynamics in the domestic fowl.

Low i.v. doses of cadmium chloride (15 micrograms Cd) given to pullets resulted in a significant reduction in urine flow (UF), glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). However, in hens treated with the heavy metal chelate FeNa EDTA prior to cadmium treatment no oliguria or reduction in GFR or ERPF was observed. It is suggested that the renal changes following the i.v. administration of cadmium to diuretic hens and alleviated in hens primed with the heavy metal chelate may result from changes in glomerular hemodynamics.