Objectives

In both systemic arterial hypertension and hypokalemic myopathy in cats a pathogenetic role of the renin-angiotensin-aldosterone system has been implicated. The aim of this study was to determine reference ranges for plasma aldosterone concentration (PAC), plasma renin activity (PRA) and the PAC to PRA ratio (ARR) in household cats. To investigate the possible influence of stress on these values, also the pituitary-adrenocortical axis was studied.

Materials & Methods

In order to obtain appropriate reference values, blood samples for the determination of the plasma concentrations of sodium, potassium, aldosterone, cortisol, adrenocorticotrophic hormone (ACTH), α-melanocyte stimulating hormone (α-MSH) and PRA were collected in 130 healthy household cats.

Results

Median values and reference ranges for PAC (235; 110-540 pmol/l), PRA (200; 60-630 fmol/l/s), and ARR (1.3; 03.-3.8) were very similar to the reference values established in the same laboratory for humans in supine position. The plasma concentrations of ACTH, α-MSH, and cortisol did not correlate significantly with PAC.

Conclusion

It is concluded that despite the fact that blood sampling was performed in cats in non-standardized positions and was associated with a wide variation of stress responses, the references ranges are similar to the relatively narrow limits established for humans in standardized position.