PLASMA-ALDOSTERONE CONCENTRATION OF CATS

Aldosterone concentrations in the plasma of specific-pathogen-free, do mestic, short-hair cats given sodium replete diets were measured by a radio-immunoassay. Plasma samples assayed were taken from male and fem ale cats of 8, 12, 17, 20, 26, 29, 40 and >52 weeks of age, from adult non-pregnant queens, and from queens in the ninth weeks of pregnancy and in the second and fifth week of lactation. Plasma aldosterone conc entration was also measured in samples taken four times over a 24 h pe riod (06:00-06:30, 11:00-11:30, 17:00-17:30 and 23:00-23:30) in a grou p of seven adult male cats. Neither age nor sex had a significant effe ct on the plasma aldosterone concentration. Also, queens had similar a ldosterone concentrations in plasma whether they were non-pregnant, pr egnant, or lactating. No circadian rhythm was observed in plasma aldos terone concentrations in adult male cats. The plasma aldosterone conce ntrations of 148 cats (87 males and 61 females, ranging in ages from 8 to >52 weeks) had a positive skew distribution with a median of 161 p mol l(-1). The upper value for plasma aldosterone concentration in hea lthy domestic cats as defined by the 95 percentile was 700 pmol l(-1).