Copper and zinc concentrations in the uterine fluid and blood serum during the bovine estrous cycle

To investigate uterine and serum copper (Cu) and zinc (Zn) concentrations variation duringthe bovine estrus cycle , 232 blood and genital tract samples were collected from the abattoir inUrmia. The phase of the estrous cycle was determined by the examination of the ovaries and theuterine tonicity. Of the 46 samples selected for use in the study, 13 were pro-estrus, 10 estrus, 8metestrus, and 15 diestrus. The uterus was incised and uterine fluid was collected by gentlescraping of the uterine mucosa with a curette. The total mean (± SEM) Cu concentrations inserum and uterine fluid samples, determined by spectrophotometry, were 66.1± 6.5 and 171.3 ±33.2μg dL-1 respectively, which were significantly different, while total mean serum and uterinefluid Zn concentrations were 91.9 ± 5.4 and 291.6 ± 23.4 μg dL-1, which also showed a significantdifference. The mean serum Cu values in different phases of the estrous cycle were notsignificantly different, while uterine fluid Cu content in pro-estrus and diestrus weresignificantly higher than those in estrus and metestrus, and were also significantly higher thanthose of the serum samples. The mean Zn value of serum samples at different stages of the cyclewas not significantly different. The mean Zn value of the uterine fluid samples was also notsignificantly different in different stages, but in pro-estrus, metestrus, and in diestrus they werehighly significantly different from those of the serum. These results showed that Cu concentrationsin the uterine fluid vary at different stages of the cycle and are higher than those in the bloodserum, but, the uterine Zn content does not vary during the estrous cycle and is much higherthan those in the serum, that seems to be due to the secretory action of the uterine mucosa.