Effects of Pergolide Mesylate on Plasma Adrenocorticotropic Hormone Concentration in Horses with Pituitary Pars Intermedia Dysfunction

Objectives The aims of this study were to validate a commercially available chemiluminescent assay for measurement of feline plasma adrenocorticotropic hormone concentration (ACTH), to determine the normal reference interval (RI) of plasma ACTH in healthy cats, to assess plasma ACTH in cats with naturally occurring hypercortisolism (HC), primary hypoadrenocorticism (PH) and other diseases (OD), and to evaluate the effect of aprotinin on plasma ACTH degradation. Methods Forty healthy cats, 10 with HC, 11 with PH and 30 with OD, were included. The chemiluminescent enzyme immunometric assay was evaluated by measurement of intra-assay precision, interassay precision and linearity. The RI for plasma ACTH in healthy cats was established using robust methods. Plasma ACTH of samples collected with and without aprotinin, stored at 4°C and assayed over a 6-day period, was measured. Results The intra-assay coefficients of variance (CVs) ranged from 2.7% to 4.3% and interassay CVs from 3.3% to 10.7%. Dilution studies showed excellent accuracy (R2 >0.99). The RI for plasma ACTH in healthy cats was 32–370 pg/ml. Plasma ACTH was not significantly different between healthy cats and the OD group. Cats with pituitary-dependent hypercortisolism (PDH) and PH had significantly higher plasma ACTH than the other groups. Plasma ACTH did not show significant differences when samples collected with and without aprotinin were compared. Conclusions and relevance The Immulite chemiluminescent assay is a valid technique for measuring plasma ACTH in cats and the RI of plasma ACTH is quite wide. Owing to the low overlap between healthy or OD cats and cats with HC or PH, the measurement of plasma ACTH appears to be useful and should be included in the diagnostic work-up when HC or PH are suspected. Furthermore, the measurement of plasma ACTH may be an accurate test for differentiating PDH from adrenal-dependent hypercortisolism.

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Effect of delayed plasma centrifugation on equine adrenocorticotropic hormone concentration

Journal of Veterinary Diagnostic Investigation ◽

10.1177/1040638719860877 ◽

2019 ◽

Vol 31 (4) ◽

pp. 585-587 ◽

Cited By ~ 1

Author(s):

Kayla N. Shepard ◽

John C. Haffner ◽

Dwana L. Neal ◽

Steven T. Grubbs ◽

Greg L. Pearce

Keyword(s):

Whole Blood ◽

Adrenocorticotropic Hormone ◽

Animal Health ◽

Pars Intermedia ◽

Plasma Acth ◽

Cornell University ◽

Diagnostic Center ◽

Acth Concentration ◽

Baseline Values ◽

The Mean

Plasma adrenocorticotropic hormone (ACTH) concentration is used in the diagnosis of pituitary pars intermedia dysfunction (PPID) in horses. We enrolled 10 horses, 5 PPID-positive and 5 PPID-negative, in our study, September 20–22, 2016. On day 0, 5 mL of whole blood was collected into each of 6 EDTA tubes and immediately placed in a refrigerator at 7°C. One tube was centrifuged within 15 min of collection, followed by centrifugation of one tube from each horse at 4, 8, 12, 24, and 36 h following collection. At each time, centrifuged plasma was pipetted into 1.5-mL polypropylene tubes and stored at −80°C. None of the plasma samples were turbid, hemolyzed, or icteric. Plasma was shipped frozen with cold packs overnight to the Animal Health Diagnostic Center of Cornell University (Ithaca, NY) for analysis. The percent change from baseline (PCFB) was reported to standardize the data given that baseline values differed. The mean PCFB was 2.8 (95% confidence interval: –2.9%, 7.0%). Neither refrigeration of whole blood for up to 36 h prior to centrifugation nor freezing affected plasma ACTH concentrations significantly.

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Impact of blue light therapy on plasma adrenocorticotropic hormone (ACTH) and hypertrichosis in horses with pituitary pars intermedia dysfunction

Domestic Animal Endocrinology ◽

10.1016/j.domaniend.2021.106651 ◽

2021 ◽

pp. 106651

Author(s):

AB Miller ◽

BA Murphy ◽

AA Adams

Keyword(s):

Blue Light ◽

Adrenocorticotropic Hormone ◽

Light Therapy ◽

Pars Intermedia

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Plasma adrenocorticotropic hormone concentration in horses decreases after freezing for 60 days

Journal of Veterinary Diagnostic Investigation ◽

10.1177/1040638719882374 ◽

2019 ◽

Vol 31 (6) ◽

pp. 856-858

Author(s):

John C. Haffner ◽

Dwana L. Neal ◽

Rhonda M. Hoffman ◽

Steven T. Grubbs

Keyword(s):

Repeated Measures ◽

Adrenocorticotropic Hormone ◽

Mixed Model ◽

Statistical Significance ◽

Hormone Concentration ◽

Plasma Acth ◽

Acth Concentration ◽

The Stability ◽

Over Time

We investigated the stability of adrenocorticotropic hormone (ACTH) in plasma after freezing for different lengths of time. The plasma ACTH concentrations of 12 horses were measured on day 0 (baseline) and over time, after stimulation with thyrotropin-releasing hormone. Samples were stored at −80°C for 3, 7, 30, 60, and 90 d, or at −20°C for 3, 7, 30, and 60 d, or between ice packs at −20°C for 3 and 7 d prior to determination of ACTH concentration. ACTH concentrations were compared to baseline (non-frozen day 0 plasma) for each storage method using a mixed model with repeated measures in which each horse served as its own control and day was the repeated effect. Statistical significance was set at p ≤ 0.05, and 0.05 < p < 0.10 was considered a trend. Plasma ACTH frozen at −20°C or at −80°C resulted in degradation of ACTH compared to baseline samples at 60 and 90 d respectively. There was no degradation of ACTH after 7 d when stored between ice packs, or before 30 d at −20°C, or before 60 d at −80°C.

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