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Pferdeheilkunde 29 721
Pferdeheilkunde 29 (2013) 6 (November/Dezember) 721-728
Use of the chasteberry preparation Corticosal®
for the treatment of pituitary pars intermedia dysfunction
in horses
Zrinjka Bradaric1, Anna May2and Heidrun Gehlen1
Clinic for Horses, Free University of Berlin1and Equine Clinic, Ludwig-Maximilian-University of Munich2, Germany
Summary
The objective of this study was to describe the efficacy of PPID treatment with the combined supplement corticosal®containing chasteberry.
Thirty-eight horses and ponies with PPID were devided into three groups and received either the chasteberry preparation (group T1) or per-
golide in addition to the chasteberry preparation (group T2) for six months or pergolide in addition to a placebo for the first three months
and pergolide in addition to the chasteberry preparation for the following three months (group T3). Clinical and laboratory examinations
were performed at three times points. Within group T1, a significant difference in clinical parameters between the first and second exami-
nation (p = 0.0042) as well as between the second and third examinations (p= 0.0001) was observed. The clinical signs improved signi-
ficantly based on the clinical overall score. On the basis of the collected data, beneficial effects of the chasteberry preparation corticosal®
on clinical parameters for PPID were determined.
Keywords: Cushing’s syndrom / horses / pituitary / epidemiology / Vitex agnus-castus / PPID
Der Einsatz des Mönchspfeffer-Präparats Corticosal®zur Behandlung des Equinen Cushing Syndroms (PPID)
Ziel dieser Studie war die Überprüfung der Wirksamkeit des mönchspfefferhaltigen Kombinationspräparats Corticosal®zur Behandlung des
Equinen Cushing Syndroms (PPID). 38 an PPID erkrankte Pferde und Ponys wurden in drei Versuchsgruppen eingeteilt und erhielten über
einen Zeitraum von sechs Monaten entweder das Kombinationspräparat (Gruppe T1) oder Pergolid zusammen mit dem Kombinationsprä-
parat (Gruppe T2) oder die ersten drei Monate Pergolid und ein Placebo und die weiteren drei Monate Pergolid und das Kombinations-
präparat (Gruppe T3). An drei Untersuchungszeitpunkten wurden die klinische Symptomatik und verschiedene Blutparameter anhand eines
festgelegten Score Systems ermittelt. In Gruppe T1 konnten sowohl zwischen den ersten und zweiten Untersuchungszeitpunkten
(p = 0,0042) als auch zwischen den zweiten und dritten Untersuchungszeitpunkten (p = 0,001) signifikante Unterschiede der klinischen
Parameter festgestellt werden. Die klinischen Symptome verbesserten sich signifikant gemessen am klinischen Gesamtscore. Anhand der
erhobenen Daten konnte ein positiver Effekt des mönchspfefferhaltigen Präparates Corticosal®auf die klinische Symptomatik von den am
Cushing Syndrom erkrankten Pferden festgestellt werden.
Schlüsselwörter: Cushing Syndrom / Pferde / Hypophyse / Epidemiologie / Vitex agnus-castus / PPID
Z. Bradaric et al.
Introduction
Pituitary Pars Intermedia Dysfunction (PPID) is a progressive
neurodegenerative disease found in aged horses and ponies
(
McFarlane
2011). Even though the cause of PPID remains
unclear, oxidative stress damaging neurons is suggested as
initial event (
Donaldson
et al. 2005). Neuronal impairment
leads to loss of dopaminergic inhibition of the pituitary pars
intermedia, resulting in melanocytic proliferation and increa-
sed production of pro-opiomelanocortin (POMC) and POMC
derivatives like adrenocorticotropic hormone (ACTH), mela-
nocyte stimulating hormone and beta-endorphin (
Donaldson
et al. 2005,
Goudreau
et al. 1992). The most commonly
used treatment is pergolide-mesilate, an ergot-alkaloid deri-
vative, which acts as D2-receptor agonist on the pituitary
gland and decreases POMC production. The efficacy of per-
golide has been proven in different studies that take the
improvement of clinical symptoms and laboratory parameters
into account (
Coursen
et al. 2001,
Beech
et al. 2002,
Divers
et al. 2002,
Corazza
et al. 2004).
It is hypothesized that Vitex agnus-castus (chasteberry) – a
medicinal plant with dopaminergic action – shows effective-
ness in the treatment of PPID by increasing dopaminergic acti-
vity in the equine pituitary. Chasteberry is a phytotherapeutic
traditionally recommended for hyperprolactinemia and pre-
menstrual syndrome in women (
Schellenberg
2001). Meier et
al. (
Berger
et al. 2000) identified diterpenes as the active sub-
stances in Vitex agnus-castus (VAC) extracts that bind to D2
and D3 pituitary receptors. The VAC extract therefore is a com-
bined D2/D3 dopamine receptor agonist. In a study perfor-
med on rats, the binding of the VAC extracts to D2 receptors
resulted in decreased prolactin secretion (
Gorkow
et al.
1994). As PPID in horses is also a D2 receptor-mediated dise-
ase, chasteberry has been evaluated as a single therapeutic.
However, compared to pergolide treatment, no improvement
of ACTH concentrations, the dexamethasone suppression test
or clinical symptoms was shown (
Beech
et al. 2002).
In Germany, a combined feed additive containing chasteberry
(Corticosal®) was specially developed for horses with PPID.
The aim of this study was to evaluate the efficacy of this spe-
cial Vitex agnus-castus preparation in the treatment of PPID
based on clinical signs and plasma ACTH, insulin and gluco-
se concentrations before, during and after administration.
Materials and Methods
Horses
Thirty-eight horses and ponies with PPID were included in this
study. The inclusion criteria were an ACTH plasma concentra-
tion >50 pg/ml and a clinical score above five. All horses
were privately owned and lived under different housing con-
ditions. In the course of the study, neither the stable environ-
ment nor the feeding regimen changed.
Group assignment
Groups were defined according to their pre-treatment. Untre-
ated horses and ponies were assigned to group T1. This was
the largest group (25 horses) and it was established to deter-
mine the efficacy of the chasteberry preparation in untreated
animals. Thirteen horses which had received pre-treatment
with pergolide were randomly divided into control groups T2
(6 horses) or T3 (7 horses). For pre-treated horses, the inclu-
sion criteria were pergolide treatment for at least three
months and no dosage changes throughout the six- month
duration of the study. For animal welfare reasons, there was
no group without any treatment.
Study period
The study period was six months, between January and
August 2011. The parameters for each horse had to be docu-
Use of the chasteberry preparation corticosal®for the treatment of pituitary pars intermedia dysfunction in horses
Pferdeheilkunde 29
722
mented for at least six months. A second examination was
performed three months after the initial examination and a
final examination took place after six months.
Treatment group definition
During the study period, the horses in group T1 received the
chasteberry preparation1only, whereas the horses in group
T2 received the chasteberry preparation and pergolide2. Hor-
ses in group T3 received pergolide for six months with the
addition of a placebo for the first three months and then swit-
ched to pergolide in addition to the chasteberry preparation
for the following three months (Table 1). Neither the owners
nor the investigator knew whether the animals received the
placebo or the active treatment. The chasteberry formulation
was administered according to the manufacturer’s instruc-
tions (0.05 g/kg PO/q24h) mixed with feed. Besides chaste-
berry, it contains phytotherapeutics like ginseng and articho-
ke, special nutrients and antioxidants. The pergolide dosage
was adjusted by the veterinarian in the field and ranged from
2 to 3g/kg PO/q24h.
Clinical examination
The same investigator performed a standardized clinical exa-
mination for PPID at different times using a composite scoring
system (Table 2) to assess clinical parameters. To avoid addi-
tional stress for the animals all examinations were performed
at the stables the horses were housed. At each examination
time, the following parameters were investigated: hypertri-
chosis, hyperhidrosis (excessive sweating), swayed back, pen-
dulant abdomen, skeletal muscle atrophy, behavior and
abnormal fat distribution. The symptoms were rated using a
score from 0 (non-existent) to 3 (severe). Furthermore, polyu-
ria and polydipsia, reported by the owners, were evaluated
Table 2 Scoring system of the typical clinical parameters of PPID (score grade 0-3)
/ Score-System der typischen klinischen Symptome von PPID
Score
0
1
2
3
hirsutism
none
hair coat long, at least visible in parts
of the body, eg. legs and lower jaw
hair coat generalized long, partly
curly
hair coat generalized
long, curly
hyperhidrosis
none
occasional localized sweating or
extensive sweating after exercise
occasional to frequent sweating
on at least two parts of the body
generalized severe
hyperhidrosis
sway back
none
minor
moderate
severe
pendulous abdomen
none
minor
moderate
severe
muscle atrophy
none
in one region of the body
in two regions of the body
generalized
behaviour
alert,
unremarkable
mildly depressed
lethargic
apathic
abnormal fat distribution
none
one body part (eg. neck, supraorbitally
or croup)
two body parts
at least three body
parts
polydypsia
no
yes
polyuria
no
yes
Table 1 Group assignment (T1-T3) and different treatment regimen /
Gruppeneinteilung (T1-T3) und unterschiedliche Behandlungsmethoden
Group
Horses
Treatment
T1
n=25
Chasteberry preparation (six months)
T2
n=6
Pergolide + Chasteberry preparation (six months)
T3
n=7
Pergolide +1.) Placebo (1st three months) 2.) Chasteberry preparation (2 nd three months)
and rated (a score of 0 if non-existent and of 1 if existent).
The evaluation of polyuria and polydipsia was performed by
the animal owner and therefore a subjective assessment
based on the state of the litter and water intake in case of
housings where watering was performed manually in drinking
troughs. Standardization of measuring polyuria and polydip-
sia was not possible due to the different housing and
management of the horses. At each examination time, an
overall score for clinical presentation was established for
each patient.
Blood examinations
At each examination time, blood samples were collected from
the horses to evaluate the efficacy of treatment. Among other
parameters, plasma ACTH as well as insulin and glucose
levels were determined after a fasting period of 12 hours. For
evaluating plasma ACTH, 4 ml venous blood was sampled
into EDTA vacutainers (Vacuette®K3, Greiner, Germany).
Samples were centrifuged immediately at 3000rpm for
15minutes to obtain EDTA plasma, which was filled into a
labelled Eppendorf vacutainer and immediately refrigerated
at +4° to +8°C until shipment on the same day. All samples
were sent to the laboratory in a cooled container and analy-
zed the following day. ACTH levels were measured using che-
miluminescence immunoassay (CLIA; Immulite 2000 XPi3,
Laboklin, Germany). A validated chemiluminescence immu-
noassay was used for determining insulin levels (Centaur XP,
Testkit IRI4, Laboklin, Germany). For evaluation of insulin,
4ml venous blood was sampled into a serum separator tube
(Vacuette®Z, Greiner, Germany) and for the evaluation of
glucose, 2 ml venous blood was sampled into a tube contai-
ning potassium oxalate and sodium fluoride (Vacuette®FX,
Greiner, Germany). All samples were sent to the laboratory
(Laboklin, Germany) and analysed by validated assays.
Statistical analysis
Analyses were carried out using the statistical software Easy-
Stat 4.4. Parameters were indicated as arithmetic mean, stan-
dard deviation and median. Correlations were made using
the same program. Statistical analysis of ACTH values bet-
ween the groups was performed by the non-parametric Kru-
skal-Wallis test and by the Wilcoxon test and by means of the
statistical software SAS®9.25. Comparison of values within
the groups was performed using univariate analysis and Stu-
dent’s t-test. Clinical scores were also analyzed with the Kru-
skal-Wallis and Wilcoxon tests. Differences were considered
statistically significant at p < 0.05. Inclusion criteria for stati-
stical analysis were at least values of two different examina-
tions per patient.
Results
Study population
The study group comprised 17 ponies, 16 warmbloods, four
thoroughbreds and one draft horse. The median age was 24
years (range, 16–38 years), 61 % of the animals were 16 to
25 years old, 66 % of the horses were kept in stables and
Z. Bradaric et al.
Pferdeheilkunde 29 723
34% on pasture. There were 22 mares (57.9 %) and 16 gel-
dings (42.1 %).
Twelve horses did not finish the full study period, eight of them
dropping out before the second examination and four before
the third. Nine of the drop-outs belonged to group T1, two to
group T2 and one to group T3. The reasons for the loss of
these twelve animals were euthanasia in eight cases (colic (2),
heart failure (2), tendon rupture, fracture, laminitis and sep-
sis) and at the request of owners (start of pergolide treatment
(2), stop of pergolide treatment and no reason given).
Clinical symptoms
Within group T1, a significant difference concerning the clini-
cal score between the first and second examinations
(p=0.0042) as well as between the second and third exami-
nations (p = 0.0001) was observed. At the third examination
time, there was no difference in clinical score between the
groups (Fig 1).
Improvement of clinical symptoms was evident to the exami-
ner at the different examination times. Especially remarkable
changes were the normalization of hair coat (Figs. 2a, b) and
behavioral changes. Owners described their horses and
ponies as more lively and alert; these behavioral changes
were also observed by the veterinarian during the examina-
tions. Hypertrichosis improved in all groups. At the beginning
of the study, all horses showed a minimum score of one or
two. The mean score for T1 and T2 was 2.4 and for T3 1.8.
There was no statistical significant difference between groups
at any time. When the third examination was performed, a
significant statistical difference was observed from that of the
first examination within each group (Fig. 3). The mean score
for T1 was 0.7, for T2 0.3 and for T3 0.8. Hyperhidrosis was
determined in 47.4 % of horses at the first examination but
was not correlated with hypertrichosis. Polydipsia and polyu-
ria were present in 33 % of the horses at the first examination
Fig. 1 Clinical overall score at first (day 1), second (after three
months) and third (after six months) examination in the different tre-
atment groups T1-T3. The difference between the first and third exa-
mination in group T1 and T2 tends to be significant (p =0.0719).
Klinischer Gesamt-Score im Rahmen der ersten (Startzeitpunkt), zwei-
ten (nach drei Monaten) und dritten (nach sechs Monaten) Untersu-
chung in den verschiedenen Behandlungsgruppen T1-T3. Der Unter-
schied zwischen der ersten und dritten Untersuchung in den Gruppen
T1 und T2 ist tendenziell signifikant (p =0.0719).
and improved to 13%. In group T1, they decreased to 7%, in
group T2 to 25% and in group T3 to 20%.
Plasma ACTH
In treatment groups T1 and T2, ACTH levels decreased slight-
ly between the first and second examinations, but increased
to above initial levels at the third examination (Fig. 4). In
Use of the chasteberry preparation corticosal®for the treatment of pituitary pars intermedia dysfunction in horses
Pferdeheilkunde 29
724
group T3, ACTH values increased slightly at the second exa-
mination and showed a slight decrease towards the third exa-
mination. The difference between treatment groups T1 and
T3 at the third examination was statistically significant
(p=0.0407). The increase within treatment group T1 was
statistically significant (p=0.0054), while the increase within
group T2 was shown not to be statistically significant
(p=0.0625).
Glucose and insulin metabolism
At each of the three examination time points, fasting levels of
insulin and glucose were measured. Based upon the referen-
ce range of the laboratory, seven horses (18.4 %) showed
hyperglycemia and three horses (7.9 %) hyperinsulinemia,
while five animals (13.2 %) had hyperglycemia combined with
hyperinsulinemia.
To sum up, 15 of 38 horses (39.5 %) suffering from PPID had
an altered glucose and insulin metabolism. Forty percent of
Fig. 3 Scores (0–3) for hypertrichosis in the different groups
(T1–T3), at first, second and third examination (p<0.05=statistical-
ly significant), T1 p =0.04, T2 p =0.001, T3 p =0.007
Auswertungen (0–3) zur Hypertrichose in den einzelnen Behand-
lungsgruppen (T1–T3) bei der ersten, zweiten und dritten Untersu-
chung (p<0.05 = statistisch verbessert), T1 p = 0.04, T2 p= 0.001,
T3 p = 0.007.
Figs. 2a and b 23-year-old Haflinger mare of group 1, at initial
examination in January 2011 (a) and at 3rd examination in July
2011 (b), showing a distinct improvement in clinical signs.
Eine 23-jährige Haflingerstute aus der Gruppe T1 zeigt eine deutliche
Verbesserung der klinischen Symptome bei der ersten Untersuchung im
Januar 2011 (a) und bei der dritten Untersuchung im Juli 2011 (b).
Fig. 5 Logarithmic delineation of insulin values at first, second
and third examination in the different groups T1–T3. * p<0.05.
Logarithmische Beschreibung der Insulinwerte der ersten, zweiten
und dritten Untersuchung in den unterschiedlichen Untersuchungs-
gruppen T1–T3. * p<0.05
Fig. 4 Endogenous ACTH levels in the course of the study, mea-
sured at the first, second and third examination in the different
groups T1–T3. The difference between T1 and T3 at the 3rd exami-
nation was determined to be statistically significant (p=0.0407).
ACTH-Werte im Verlauf der Studie, gemessen zum ersten, zweiten
und dritten Untersuchungszeitpunkt in den Behandlungsgruppen
T1–T3. Der zwischen T1 und T3 im Rahmen der dritten Untersu-
chung ermittelte Unterschied war statistisch signifikant (p =0.0407).
a
b
Use of the chasteberry preparation corticosal®for the treatment of pituitary pars intermedia dysfunction in horses
Pferdeheilkunde 29
726
these horses were treated with pergolide. In the course of the
study, no improvement in glucose and insulin metabolism was
observed. Regarding insulin values, a significant difference
between T1 and T3 as well as between T2 and T3 was evident
at the second examination time. Insulin values in treatment
group T3 were considerably higher compared to the other
treatment groups (Fig. 5). Glucose levels showed no differen-
ce between the different treatment groups at any time during
the study period. ACTH levels did not correlate with insulin
and glucose values. Insulin and glucose levels showed a wide
variance in horses with similar ACTH values.
Laminitis
Twenty-four horses (63.2%) of the study group had had lam-
initis before. At the beginning of the study no horse or pony
showed laminitis. In the course of the study, two ponies deve-
loped acute laminitis following the second examination. One
horse belonged to group T1 and one horse to group T2. Both
ponies had been out on pasture before development of acute
laminitis and showed increased insulin and glucose levels at
the second examination.
Discussion
Regarding the study population, the ratio of warmbloods to
ponies was quite balanced. According to other studies, there
was no breed predilection for PPID (
McFarlane
2011,
McGo-
wan
2008,
McGowan
2008). The average age was 24 years.
An average age of 20 years was described in a study by
Breu-
kink
et al. (1995). PPID can also be recognized in younger
horses, as previous studies have shown (
Baumgartner
et al.
1990,
Brüns
2001,
Sommer
2003). There was no relations-
hip between age or breed and the treatment received. The
proportion of mares (58%) was higher than that of male hor-
ses (42%) but no statistically significant sex difference was
determined. Other studies did not show any sex predilection
for developing PPID either (
Breukink
et al. 1993,
Couëtil
et
al. 1996,
Schott
2002).
This study had no control group without any treatment for ani-
mal welfare reasons, as PPID is a severe disease leading to
an impaired quality of life for the affected horses. The disease
takes a progressive course and improvement of symptoms
cannot be expected without therapy (
McFarlane
2011,
Breu-
kink
et al. 1995,
Schott
2002).
Concerning clinical signs, a significant improvement was
observed within treatment group T1. These horses, which had
not received any treatment before, responded well to the cha-
steberry preparation. At the third examination after six
months, almost no difference was observed between group
T1 and the control groups T2 and T3 which had been treated
with pergolide. Based on the overall clinical score it can be
concluded that clinical symptoms improved significantly
based on the overall clinical scores. Treatment with the cha-
steberry preparation resulted in a significant clinical improve-
ment in the previously untreated animals. Compared to
group T1, the influence of the chasteberry preparation on
horses receiving constant pergolide medication was much
lower. This can be explained by the proven efficacy of pergo-
lide treatment in PPID horses (
Beech
et al. 2002,
Divers
2008), indicating that the dosage was appropriate for them.
Between the first and second examinations, all three groups
showed a distinct reduction in the overall clinical score, a fact
partly based upon the seasonal shedding of the hair coat.
However, owners reported delayed or no shedding of hair
coat in the years before. Even horses which had received per-
golide before showed a great improvement in hypertrichosis
when they were fed the chasteberry preparation compared to
previous years. To conclude, the chasteberry preparation see-
med to have a great influence on the parmeter hypertrichosis
and shedding of the hair coat. Furthermore, behavioral chan-
ges were observed. The patients became more alert throug-
hout the study and owners reported positive mental develop-
ment. This was not only based on subjective statements by the
owners but was also noticed by the investigator.
Acute laminitis occurred once in group T1 and once in group
T2. Both horses had already experienced laminitic episodes
before and acute laminitis occurred shortly after the second
examination, after they had been taken out to pasture. This
shows the inability of the chasteberry preparation to prevent
laminitis either alone or in combination with pergolide treat-
ment in patients with a preexistent condition when they have
access to pasture.
To date, only one study has evaluated the potency of a chaste-
berry preparation in horses with PPID. Beech et al. (
Beech
et al.
2002) observed no positive effect of Vitex agnus-castus on cli-
nical symptoms, some horses even showed deterioration of
PPID symptoms. The study used Vitex agnus-castus extract
without further information regarding its concentration or other
ingredients. On the other hand, the chasteberry preparation
used in this study is specially developed for horses with PPID
and contains not only chasteberry but other useful phytothera-
peutics and nutrients. The chasteberry showed dopamine-ago-
nistic properties and in combination with the other ingredients
it could be responsible for improving the other parameters like
shedding of hair coat or improvement of behavior.
ACTH plasma levels decreased between the first and second
examination in treatment groups T1 and T2, but they increa-
sed in group T3. These variations might be explained by the
influence of the chasteberry preparation, although the diffe-
rences were not statistically significant.
Between the second and third examinations, plasma ACTH
levels increased markedly in treatment groups T1 and T2.
This increase was statistically significant within group T1 bet-
ween the first and third examination. Furthermore, the diffe-
rence between treatment group T1 and T3 at the third exami-
nation was statistically significant. Although clinical symptoms
improved, the ACTH levels increased in group T1 and in
group T2. This is contrary to a study of Donaldson et al.
(2002), in which ACTH values normalized in 60% of the hor-
ses under pergolide.
As the increase occurred in the pergolide-treated group as
well, other factors must also be present to influence ACTH
values. If the ACTH increase was only due to the inefficacy of
the chasteberry preparation, no increase would be measura-
ble in the pergolide-treated group. Different studies showed a
Z. Bradaric et al.
Pferdeheilkunde 29 727
seasonal influence on ACTH levels. Plasma ACTH levels are
higher in early fall (August to October) due to a reduction of
daylight and decline in winter, reaching their lowest levels in
January (
Beech
et al. 2009,
Copas
et al. 2012,
Elliott
2010).
In a recent study performed by
Funk
et al. (2011), a stronger
reaction of ACTH levels after TRH stimulation in July than in
February was seen.
In the present study, the characteristic clinical symptoms and
ACTH values did not correlate. While clinical symptoms
improved with therapy, ACTH values increased. Until now,
determination of ACTH values has been regarded as the
parameter of choice to evaluate efficacy of treatment and to
change the dosage if needed.
As clinical symptoms improved considerably during the cour-
se of the study, adjustment of dosage was not necessary.
However, the question arises whether monitoring of ACTH
values is essential for adjustment of dosage or whether chan-
ges in dosage should be rather be based upon development
of clinical symptoms.
On initial examination 39.5% of horses and ponies showed
alterations in their insulin and glucose metabolism. In the lite-
rature up to 60 % of the patients suffering from PPID show
elevated serum insulin concentrations (
McFarlane
2011).
40% of the horses in the current study with alterations in insu-
lin and glucose metabolism were treated with pergolide. The
results suggest that pergolide treatment does not necessarily
lead to the regulation of insulin and glucose metabolism.
In the course of the study, the ratio of horses with altered glu-
cose and insulin metabolism did not improve. A possible cau-
se could be variations in access to pasture. In January and
February, at the initial examination horses were not taken out
on pasture and, apart from concentrated feed, no other sour-
ce of starch was available. During the pasture season, the
ratio of horses showing insulin resistance increased.
Other authors have also described a relation between grass
intake and altered equine metabolism (
McGowan
2008,
Kronfeld
2006,
Adair
et al. 2008). The placebo group sho-
wed significantly higher insulin levels at the second examina-
tion time than the groups receiving the chasteberry prepara-
tion. It can be concluded that the chasteberry preparation
seemed to have an influence on insulin levels.
Limitations of data collection
The limitation in performing this study was the failure rate wit-
hin the study population mostly due to reasons other than
PPID. Because of the failure rate, the groups were reduced
and only 26 horses could be analyzed at the final examina-
tion. Groups T2 and T3 became quite small for statistical
analysis and the results must be observed critically. A study
analyzing long-term effects of pergolide therapy showed a
low survival time of 7.9 months in horses with PPID (
Graubner
et al. 2010). Patients included in these kinds of studies are
generally old and in advanced stages of PPID.
For a better understanding of the increase of plasma ACTH
under the chasteberry preparation and pergolide in August,
horses should have been examined at the beginning of the
year again when lower ACTH levels are generally expected
due to seasonal variations in pituitary activity.
Conclusion
Based on the results of this study, the chasteberry prepara-
tion represents a treatment option for horses with PPID.
Especially in cases in which horses do not tolerate pergolide
treatment or owners decide against pergolide medication,
the chasteberry preparation may serve as an alternative. To
determine the long-term effect on clinical signs and labora-
tory parameters, further studies need to be performed. Con-
tinuing studies on the chasteberry preparation in combina-
tion with individually optimized stabling conditions and fee-
ding regimens should be carried out in order to determine
the effect on the disease state. These potential studies would
be useful in determining disease progression under the
influence of the chasteberry preparation. Furthermore,
results could be compared with those of horses treated with
pergolide. To sum up, the collected data provides evidence
of the positive effects that this special chasteberry prepara-
tion has on the clinical symptoms of horses and ponies suf-
fering from PPID. Quality of life was improved in the study
population.
Conflict of interest statement
None of the authors has any financial or personal relation-
ships that could inappropriately influence or bias the content
of the paper.
Manufacturer’s addresses
1.Corticosal®, Navalis Nutraceuticals GmbH, Filderstadt,
Germany
2Prascend®, Boehringer Ingelheim, Ingelheim, Germany
3Immulite 2000XPi, Siemens, Eschborn, Germany
4CentaurXP, Testkit IRI, Siemens, Eschborn, Germany
5SAS®9.2, SAS Institute Inc., Cary, USA
Abbreviations
ACTH Adrenocorticotropic hormone
PPID Pituitary Pars Intermedia Dysfunction
ml Milliliters
pg/ml Picogram per milliliter
POMC Proopiomelanocortin
VAC Vitex agnus-castus
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