Effects of cadmium ingestion on plasma and osmoregulatory hormone concentrations in male and female Pekin ducks.
Effects of ingested cadmium (Cd) on body mass and plasma, urine, salt-gland secretion, and osmoregulatory hormone concentrations were assessed in male and female Pekin ducks, Anas platyrhynchos, acclimated to 450 mM NaCl over 6 wk and then held an additional 13 wk on 300 mM NaCl (prolonged saline exposure). Groups of six birds ate diets containing 0 (control), 50 (low-Cd diet), or 300 (high Cd diet) micrograms Cd/g food. Ducks that ingested Cd, especially females, lost body mass. Cadmium ingestion did not affect salt-gland secretion concentration. Control males had higher plasma osmolality and lower relative plasma volume. These increased in both sexes during saline acclimation. The high-Cd diet suppressed the increase in plasma osmolality in both sexes, but a rise in relative plasma volume occurred only in females. Following prolonged exposure to saline, plasma osmolality and relative plasma volume were reduced in control ducks but further elevated in ducks on the high-Cd diet. Cadmium ingestion suppressed the increase in urine osmolality that occurred in control ducks during saline acclimation. Neither saline acclimation nor Cd ingestion affected plasma concentrations of arginine vasotocin or prolactin. Arginine vasotocin was not correlated with plasma osmolality; prolactin was negatively correlated with plasma osmolality, but only in males. Cadmium suppressed the increase in angiotensin II that occurred at higher salinities in control and low-Cd males. This study examined the effects of gradually increasing body cadmium content on osmotic homeostasis. Cadmium affected plasma and urine, but not salt-gland secretion, concentrations and some of these responses were sexually disparate. Cadmium did not affect osmoregulatory hormones (arginine vasotocin and prolactin) by which observed changes in plasma concentration might have been influenced.
Hughes
Maryanne R
MR
Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, BC V6T 1Z4, Canada. hughes@zoology.ubc.ca
Bennett
Darin C
DC
Gray
David A
DA
Sharp
Peter J
PJ
Scheuhammer
Anton M
AM
Elliott
John E
JE
D000284:Administration, Oral; D000821:Animal Feed; D000818:Animals; D015992:Body Mass Index; D002104:Cadmium / Q000008:administration & dosage / Q000009:adverse effects*; D004372:Ducks / Q000502:physiology*; D004785:Environmental Pollutants / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D008297:Male; D009994:Osmolar Concentration; D011388:Prolactin / Q000494:pharmacology; D012491:Salt Gland / Q000187:drug effects / Q000502:physiology; D012737:Sex Factors; D014668:Vasotocin / Q000494:pharmacology; D014882:Water-Electrolyte Balance / Q000187:drug effects*
D004785:Environmental Pollutants; D002104:Cadmium; D011388:Prolactin; D014668:Vasotocin