Variation in plasma adrenocorticotropic hormone concentration and dexamethasone suppression test results with season, age, and sex in healthy ponies and horses.

Donaldson MT, McDonnell SM, Schanbacher BJ, Lamb SV, McFarlane D, Beech J.

Department of Clinical Studies-New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA, USA. mtd@vet.upenn.edu

The purpose of this study was to evaluate the variation in plasma adrenocorticotropic hormone (ACTH) concentration and dexamethasone suppression test (DST) results with season, age, and sex in healthy, pony mares (n=15) and pony stallions (n=14) living under semiferal conditions and horse mares (n=10) living at pasture. Plasma ACTH concentrations were measured in September 2002, and in January, May, and September 2003. DSTs were performed in January and September 2003. Plasma ACTH concentrations in September 2002 and September 2003 were similar and were significantly greater than in January and May (P < .001). Plasma ACTH concentration was within the reference range for 38 (97 % ) of 39 subjects in January, for 39 (100 % ) of 39 subjects in May, for 2 (5 % ) of 39 subjects in September 2002, and for 3 (8 % ) of 39 subjects in September 2003. DST results were within the reference range in all subjects in January and were within the reference range for 29 (74 % ) of 39 subjects in September 2003. Plasma cortisol concentration at the end of the DST was significantly greater in September than in January (P = .002). Age was positively correlated with plasma ACTH and plasma cortisol concentration at the beginning and end of the DST Within the same season, plasma ACTH concentration in pony mares, pony stallions, and horse mares was not significantly different (P > .05). Seasonal changes in plasma ACTH concentration and DST results should be considered when interpreting endocrine test results.

in: J Vet Intern Med. 2005 Mar-Apr;19(2):217-22.

Da gerade September ist, hole ich das hier mal hoch.

Achtet auf Eure Cushing-(Verdachts-)Pferde, für sie beginnt gerade eine schwierige Zeit.

LG

sag mal kann da nicht mal wer der Englisch kann eine Anfrage zu den Blutwerten machen??

Variation in plasma adrenocorticotropic hormone concentration and dexamethasone suppression test results with season, age, and sex in healthy ponies and horses.

Donaldson MT, McDonnell SM, Schanbacher BJ, Lamb SV, McFarlane D, Beech J.

Department of Clinical Studies-New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA,

  mtd@vet.upenn.edu

J Am Vet Med Assoc. 2007 Aug 1;231 (3):417-26 17669045 (P,S,E,B,D)
Adrenocorticotropin concentration following administration of thyrotropin-releasing hormone in healthy horses and those with pituitary pars intermedia dysfunction and pituitary gland hyperplasia.

Jill Beech, Raymond Boston, Sue Lindborg, Gail E Russell

"Objective-
To compare the effect of thyrotropin-releasing hormone (TRH) administration on endogenous ACTH concentrations in healthy horses and those with pituitary pars inter-media hyperplasia and compare the test with the dexamethasone suppression test (DST).
Design-
Prospective case series. Animals-15 horses with clinical signs of pituitary pars intermedia dysfunction (PPID), 4 horses with equivocal signs of PPID, and 29 horses without signs of PPID.
Procedures-
ACTH concentrations prior to and after administration of TRH were measured 61 times in 48 horses. Results of the DST (cortisol response) were compared with those of the TRH test in 29 horses. Thirty-three horses (24 with no clinical signs of PPID, 5 with clinical signs of PPID, and 4 with equivocal clinical signs of PPID) were euthanized and necropsied and their pituitary glands evaluated. Results-ACTH concentrations increased in all horses, but magnitude and duration of increase were significantly higher in horses with PPID. Endogenous ACTH concentrations were influenced by season. The ACTH baseline concentrations and response to TRH were not correlated with results of the DST. Results of DST were abnormal only in clinically abnormal horses or those with pars intermedia hyperplasia, but were within reference range in 17 of 26 tests in these horses.
Conclusions and Clinical Relevance-
The DST was specific but not sensitive and was inconsistent for individuals, and results often did not agree with the TRH test response. "

Hallo Meike,
habe erst einen Wert von Januar und März. Kann also erst im kommenden September was dazu sagen 

Gruss Esther