{
  "abstract": "Background\n\nNo simple, blood-based biomarker to estimate tumor size in dogs with pituitary-dependent hypercortisolism (PDH) has been evaluated.Hypothesis/objectives\n\nDetermine whether the adrenocorticotropic hormone (ACTH)/cortisol ratio differentiates pituitary microadenomas from macroadenomas in dogs with PDH and correlates with pituitary size.Animals\n\nSeventy privately-owned dogs with PDH (microadenomas, n = 30; macroadenomas, n = 40).Methods\n\nRetrospective multicenter observational study. Endogenous ACTH and cortisol concentrations obtained at the same time point before treatment were used to calculate the ACTH/cortisol ratio. Pituitary tumor size was classified using the pituitary-to-brain (P/B) ratio. Diagnostic performance was evaluated using receiver operating characteristic analysis and multivariable logistic regression.Results\n\nDogs with macroadenomas had significantly higher ACTH/cortisol ratios than dogs with microadenomas (median, 9.12; IQR, 6.46-14.28 vs median, 4.90; IQR, 3.08-8.10; P < .001). The ratio showed moderate discrimination for differentiating macroadenomas from microadenomas with an area under the curve of 0.77 (95% CI, 0.66-0.89; P < .001). A cutoff >5.69 yielded 85% sensitivity and 60% specificity (positive likelihood ratio 2.13), whereas a higher ratio >11.74 achieved 90% specificity and 35% sensitivity (positive likelihood ratio 3.50). The ACTH/cortisol ratio showed moderate positive correlation with pituitary size (Spearman's ρ = 0.48; 95% CI, 0.26-0.64; P < .001) and remained independently associated with macroadenoma classification in multivariable analysis (OR, 1.19; 95% CI, 1.05-1.40).Conclusions and clinical importance\n\nThe ACTH/cortisol ratio is associated with pituitary tumor size in dogs with PDH and may support clinical risk stratification, particularly when advanced imaging is unavailable.",
  "abstract_shown": true,
  "affiliations": [
    "Small Animal Practice, Paphos 8300, Cyprus.",
    "Animal House Veterinary Clinic, Capoterra 09012, Italy.",
    "Joint Department of Veterinary Medicine, Faculty of Applied Biological Science, Gifu University, Gifu 501-1193, Japan.",
    "Department of Veterinary Medical Science, University of Bologna, Ozzano dell'Emilia, Bologna 40064, Italy."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 7,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "George Stylianou",
      "orcid": "0009-0000-7919-5223"
    },
    {
      "affs": [
        1
      ],
      "name": "Federico Vassallo",
      "orcid": "0009-0005-5428-3135"
    },
    {
      "affs": [
        2
      ],
      "name": "Naohito Nishii",
      "orcid": "0000-0003-2173-5420"
    },
    {
      "affs": [
        3
      ],
      "name": "Alessia Diana",
      "orcid": "0000-0003-1709-3920"
    },
    {
      "affs": [
        3
      ],
      "name": "Antonio M Tardo",
      "orcid": "0009-0009-3636-0415"
    },
    {
      "affs": [
        3
      ],
      "name": "Francesca Del Baldo",
      "orcid": "0000-0002-5577-0657"
    },
    {
      "affs": [
        3
      ],
      "name": "Federico Fracassi",
      "orcid": "0000-0003-3121-2199"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9qnbjbrpnyqsa.bib",
  "cited_by": 0,
  "doi": "10.1093/jvimsj/aalag269",
  "fulltext_url": "https://europepmc.org/articles/PMC13718425",
  "id": "9qnbjbrpnyqsa",
  "issns": [
    "0891-6640",
    "1939-1676"
  ],
  "landing_url": "https://europepmc.org/article/MED/42955823",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "AcademicSubjects/SCI01400"
    ],
    [
      "heading",
      "Original Research"
    ],
    [
      "heading",
      "Small Animal Internal Medicine Endocrinology"
    ],
    [
      "openalex",
      "2712|Pituitary Gland Disorders and Treatments"
    ]
  ],
  "openalex": "W7224174267",
  "pdf_url": "https://europepmc.org/articles/PMC13718425?pdf=render",
  "pmcid": "PMC13718425",
  "pmid": "42955823",
  "published": "2026-09-01",
  "publisher": "Oxford University Press",
  "ris": "https://research.draconitic.com/paper/9qnbjbrpnyqsa.ris",
  "sources": [
    {
      "first_seen": "2026-11-01T00:20:45Z",
      "native_id": "MED:42955823",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42955823"
    },
    {
      "first_seen": "2026-11-02T12:22:27Z",
      "native_id": "PMC13718425",
      "source": "pmc",
      "url": "https://doi.org/10.1093/jvimsj/aalag269"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2712|Pituitary Gland Disorders and Treatments",
      "subfield": "endocrinology-metabolism"
    }
  ],
  "title": "Utility of the ACTH/cortisol ratio for differentiating pituitary microadenomas from macroadenomas in dogs with pituitary-dependent hypercortisolism.",
  "title_text": "Utility of the ACTH/cortisol ratio for differentiating pituitary microadenomas from macroadenomas in dogs with pituitary-dependent hypercortisolism.",
  "type": "peer-reviewed",
  "updated_at": "2026-11-02T12:22:27Z",
  "url": "https://research.draconitic.com/paper/9qnbjbrpnyqsa",
  "venue": "Journal of veterinary internal medicine",
  "versions": []
}