Multiple corticosteroid abnormalities in cats with hyperaldosteronism

Abstract

Background: The frequency with which multiple corticosteroid abnormalities occur in cats with aldosterone secreting adrenocortical tumors is unknown.

Objectives: To evaluate adrenal-derived corticosteroids in cats in which blood samples were submitted for measure of aldosterone.

Animals: Two hundred ninety-seven cats.

Methods: Retrospective study. Analysis of a convenience sample of previously submitted serum or plasma. Progesterone, corticosterone, and cortisol were measured in feline serum or plasma samples submitted to an endocrinology laboratory for aldosterone measurements. Demographics and clinical history were retrieved from submittal forms when provided. Statistical testing was performed to investigate associations among the adrenal corticosteroids.

Results: Progesterone and corticosterone concentrations were strongly correlated (ρ = 0.74; P < .001). Progesterone (median, 5 nmol/L; interquartile range, 3-10 nmol/L) and corticosterone (113 nmol/L, 38-250 nmol/L) in cats with markedly increased aldosterone concentrations (≥3000 pmol/L) were higher than progesterone (1 nmol/L, 1-2 nmol/L) and corticosterone (12 nmol/L, 3-25 nmol/L) in cats with normal aldosterone concentrations (P < .001 for both comparisons). Progesterone concentrations ≥10 nmol/L (normal, ≤2 nmol//L) occurred in 24 of 76 (32%) cats with aldosterone concentrations ≥3000 pmol/L. Cortisol was lower in cats with aldosterone concentrations ≥3000 pmol/L as compared to those with aldosterone concentrations <500 pmol/L (59 nmol/L, 27-103 nmol/L vs 103 nmol/L, 49-182 nmol/L; P = .002).

Conclusions and clinical importance: Multiple corticosteroid abnormalities occur in a subset of cats with hyperaldosteronism. The magnitude of increases in progesterone and corticosterone in some cats with hyperaldosteronism is likely to be clinically relevant.

Keywords: adrenal cancer; corticosterone; cortisol; progesterone.

FIGURE 1

Box‐and‐whisker plots depicting baseline concentrations of (A) progesterone, (B) corticosterone, and (C) cortisol when grouped by baseline aldosterone concentrations of: <500 pmol/L (n = 92), 500‐999 pmol/L (n = 58), 1000‐2999 pmol/L (n = 71), and ≥3000 pmol/L (n = 76). The horizontal line within each box represents the median, the lower and upper boundaries of each box represent the 1st and 3rd quartiles, and the whiskers represent the 5%‐95% range. Dots represent individual values outside of this range. The dashed horizontal lines in each panel represent the reference interval. Kruskal‐Wallis testing with Dunn's post hoc testing was used for comparisons of hormone concentrations across groups. *P = .005, **P = .002, ***P ≤ .001

FIGURE 2

Scatterplots depicting (A) progesterone and corticosterone concentrations in the entire study population of 297 cats, (B) progesterone and cortisol concentrations in the 126 cats with progesterone concentrations exceeding the RI, and (C) corticosterone and cortisol concentrations in the 132 cats with corticosterone concentrations exceeding the RI. Cats with normal to moderately increased aldosterone concentrations (<1000 pmol/L) are depicted by black dots. Cats with severely (1000‐2999 pmol/L) and markedly increased (>3000 pmol/L) aldosterone concentrations are depicted by blue triangles and red squares, respectively. The Spearman's correlation coefficient (ρ) and associated P values are shown in the upper‐right of each panel