Non-invasive monitoring

Stress and the measurement of

glucocorticoids and their metabolites in

different matrices

Erich Möstl

Veterinary University Vienna

Veterinärplatz 1

1210 Vienna

Dairycare, Bern

Focusof the presentation:

Glucocorticoids are „anti-stress“ hormones

Glucocorticoids are mainly excreted as

metabolites. The concentration is a

parameter for glucocorticoid production

(activity of the HPA-axis)

Some glucocorticoid metabolites are

biologically active substances

Dairycare, Bern, E. Möstl 2015 2

Dairycare, Bern, E. Möstl 2015

….is the response of an organism to a stressor

Stress

3

Glucocorticoids help the organism to

overcome stressors

Regulating the metabolism

Immunological effects

Effects on reproduction, behaviour, food intake, wound

healing…

Transgenerational effects

Involved in the hormonal cascade inducing parturition,

developmental effects, cognition…….

Stress

Welfare as absence of stress?

(Yerkes-Dodson law). Arousal und Performance

No standard definition of stress, but a need for additional biochemical or endocrine parameters to measure it.

During stressful situations, often increased

amounts of hormones are produced , but a lot

of activities can cause a hormonal increase.

Dairycare, Bern, E. Möstl 2015 4

Dairycare, Bern, E. Möstl 2015 5

Glucocorticoids (GCs)

Glucocorticoids are by definition a class of steroid

hormones that bind to the glucocorticoid receptor

and have an effect .

Catecholamines

Adrenaline (Epinephrine) /Noradrenaline

Frontline hormones of

stress reactions are the

Dairycare, Bern, E. Möstl 2015 6

Hypothalamus

CRH

ACTH

Neurotransmitter

Hypophysis

CNS

Local

influences

Excretion

Deactivation

Effects

Re-activation

Extra-adrenal

glucocorticoid

production

Glucocorticoids

Peripheral tissue

Adrenal cortex

G. Talaber et al., Local glucocorticoid production in the thymus,

Steroids (2015),

http://dx.doi.org/10.1016/j.Steroids.201506.010

Slominski et al., On the regulation of local and systemic

steroidogenic activities. Steroids (2015),

http://dx.doi.org/10.1016/j.steroids.2015,04.006

Cortisol and Corticosterone

Dairycare, Bern, E. Möstl 2015 7

C O

OH

O

H3C

HO

CH2OH

H3C C O

O

H3C

HO

CH2OH

H3C

Cortisol and corticosterone independence in cortisol-dominant wildlife

L. Koren et al., Gen. Comp. Endo., 2012

Why do humans have two glucocorticoids: A question of intestinal

fortitude

D. J. Morris, Steroids, 2015

Dairycare, Bern, E. Möstl 2015 8

Transport of GCs in the blood

Non-bound (free) GC

CBG- bound

Albumine bound

Solubility of cortisol in water: 0.28 mg/ml (http://www.vetpharm.uzh.ch/reloader.htm?wir/

00000005/0237_01.htm?wir/00000005/0237_00.htm)

Cortisol Binding Globulin

(CBG)

Dairycare, Bern, E. Möstl 2015 9

CBG influences local GC

concentrations

CBG – cortisol binding is decreased with

increasing temperature

A small increase in temperature

(inflammation) causes a higher local

proportion of „free“ cortisol

Temperature-responsive release of cortisol from its

binding globulin: a protein thermocouple. Cameron et

al. J. Clin. Endocrinol. Metab., 2010

Dairycare, Bern, E. Möstl 2015 10

The tissue concentration of cortisol

is context sensitive

Cortisol

Cortisone Corticosterone

11ß-hydroxysteroid dehydrogenase

11ß-hydroxysteroid + NADP 11-oxosteroid + NADPH

Sample matrix

Dairycare, Bern, E. Möstl 2015 11

Blood

Saliva

Milk

Urine

Faeces

Hair

Claw

horn

Time post stressor

Now past

8%

92%

7%

93%

18%

82%

59% 41% 72% 28%

77% 23%

Excretion of 14C-Cortisol via faeces ( ) and urin ( )

Dairycare, Bern, E. Möstl 2015 12

Palme+Mostl-2001-KTBL 403,9-17

simple and

easy to collect

Advantages of faeces

as sample material

not stressful

for the animal

enables large scale,

longitudinal studies

What happened a certain time

(e.g.: 12 h in ruminants) ago?

even possible in zoo and

wild animals

Dairycare, Bern, E. Möstl 2015 13

ho

urs

afte

r th

e e

nd

of th

e in

fusio

n

Sheep Pony Pig

24

48

72

96

120

0

Palme et al., 1996

Anim. Reprod. Sci. 43, 43-63

Delay of faecal peak radioactivity

after infusion of 14C-Steroids

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HPLC-fractions

There is a species specific

metabolic pattern of glucocorticoid metabolism

Metabolic pattern of 14C glucocorticoids in faeces

after i.v. infusion

Dairycare, Bern, E. Möstl 2015 16

Influence of sampling time

With increasing time after

infusion of 14C-cortisol

the excreted metabolites

increased in polarity

TLC:

Consecutive chromatography

using chloroform/acetone

14 + 6

16 + 4

18 + 2

Cortisol

Progesterone

Days after infusion

Urine

Faeces

L iver

G ut

Cortiso l

Lexen et al., Vet.Med.Austria 95 (2008), 64-71

Dairycare, Bern, E. Möstl 2015 17

Molecular weight

(LC-MS ) 302

304

306

304

306

308

350

306

350

350

Fractions

0 10 20 30 40 50 60 70 80 90 100

0

25

50

75

cp

m/g

fa

ece

s (

x1

00

) HPLC/MS of 14C-cortisol metabolites

Straight Phase

HPLC

Faeces of

sheep

Möstl et al, 2002

MW 300= C19O3

MW 350 = C21O3

Cortisol MW = 362.5

Dairycare, Bern, E. Möstl 2015 18

Side chain cleavage

11-oxoaetiocholanolone

HO

H3C

O H3C

H

O

11,17-dioxoandrostanes

(11,17-DOA)

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Formula and structure

5a-Steroid

5ß-Steroid

The diffference in the formulas is a small

broken line instead of a straight line, but

the shape of the two molecule differ !

The analytical repertoire used is similar

as in doping control

Mass spectrometry (combined with CG or

HPLC)

Immunoassays (RIA, EIA or FIA)

21

Mass spectrometry and immunoassays….

Taylor et al., (2015) European J. Endocrinol., 173

Dairycare, Bern, E. Möstl 2015

How to measure those substances ?

The tools:

22

Specificity of immunoassays -

a problem of comparing results

between labs / assays

O O

O H

O

O O

HO H

they are group specific

Möstl et al., 2005 Ann.N.Y. Acad. Sci. 1046:17-34 Dairycare, Bern, E. Möstl 2015

Antibodies „palpate“ parts of the molecules

Dairycare, Bern, E. Möstl 2015 23

Generalized fecal glucocorticoid assay? (Wasser et al., 2000. Gen. Comp. Endo.

120; 260-75

---- „Basal level“

---- „Stress-level“

C Biological validation

Biological sensitivity

Chemical validation

Extraction

Dilution

Immunoassay

Defrosting

------ „Blank“ value

Validity of the assay

Serial dilution

Fraction

Co

ncen

trati

on

Problem of „blank“-

values

Dairycare, Bern, E. Möstl 2015 24

Days before and after ACTH-administration

0 1 2

0

40

80

120

Cort

isol (n

mol/l pla

sm

a)

Stimulation of the adrenal cortex

25

Cow ACTH (16 µg, i.v.)

0

500

1000

1500

2000

Fa

eca

l C

M (

nm

ol/kg

)

What is best: Area under the curve

or absolute value?

Palme et al., 2000

Transport – stress

11,1

7-D

ioxoandro

sta

nes

(nm

ol/kg f

aeces)

Days after transport

0 1 2

0

150

300

450

600

750

26 Dairycare, Bern, E. Möstl 2015

Variation of cortisol concentrations

in the blood of cows (n=10)

8:00 14:00 8:00 11:00 20:00 17:00 2:00 5:00 23:00

Time of day

Max/Min: 35

Co

rtis

ol (p

erc

en

tage

of th

e m

ed

ian

)

10

100

1000

27 Dairycare, Bern, E. Möstl 2015 27

Co

rtis

ol m

eta

bo

lite

s

(pe

rce

nta

ge

of th

e m

ed

ian

) Variation of faecal cortisol

metabolites„ concentrations in cows (n=10)

Max/Min: 3.8

8:00 14:00 8:00 11:00 20:00 17:00 2:00 5:00 23:00

Time of day

10

100

1000

28 Dairycare, Bern, E. Möstl 2015 28

29

„Free“ glucocorticoids are excreted

Urine

Faeces

Liver

Gut

Adrenals

Metabolism in

other organs

This is known for urine,

but in faeces?

Dairycare, Bern, E. Möstl 2015 29

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Immunisation of sheep against

cortisol C O

O H

O

H 3C

HO

CH 2O H

H 3CO H

O

H 3C

HO

CH 2O H

H 3C

Plasma cortisol

(ng/ml)

FCM (immunoreactive

11-oxoetiocholanolone)

ng/g wet faeces

8 18

wks after imm.

8 18

wks after imm.

Minutes after ACTH Hours after ACTH

H O

H 3C

OH 3C

H

O

H O

H 3C

OH 3C

H

O

before

imm.

before

imm.

0 4 8 12 0 4 8 12 0 4 8 120 54060 0 540600 54060

0

500

1500

2500

3500

0

50

100

150

200

250

Correlation plasma – faeces

Plasma Most of the cortisol is

protein bound

Low concentration of

metabolites

Faeces Metabolites of the

unbound fraction of

the hormone

Dairycare, Bern, E. Möstl 2015 31

Do faecal cortisol metabolites and

plasma cortisol tell the same story?

Sheriff et al., 2010: Gen.Comp. Endo. 166; 614-19

CBG- bound

Concentration of

immunoreactive FCM after

defaecation (cows)

32

Horak and Möstl (2014) Vet. Med. Austria / Wien. Tierarztl. Mschr. 100, 24-33

Boldenone formation.. Arioli et al., 2008, Rapid comunications in mass spectrometry

Dairycare, Bern, E. Möstl 2015 32

Are glucocorticoid metabolites

anabolic or catabolic in cattle?

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“Improved feed efficiency and FCM levels

over the finishing phase”

Montanholi et al., Livestock Science155 (2013),130–136

European Community 2008. Commission staff working document on

theimplementation of national residue monitoring plans in the member

states in2007 (Council Directive 96/23/EC). Brussels, 23.12.2008.

Retrieved May 11,2011, from

http://ec.europa.eu/food/food/chemicalsafety/residues/workdoc

An androgenic substance in feces from cattle as

demonstrated by tests on the chick. Riley GM, Hammond JC. 1942. Endocrinol 31: 653–658.

Cortisol and 11,17-DOA in the bile

(cow)

pg/well

Fraction

0

200

400

600

0 20 40 60 80 95

0

200

400

600

0 20 40 60 80 95

Fraction

Cortisol 11,17-DOA

Dairycare, Bern, E. Möstl 2015 34

Standardisation of results

Wet or dry weight?

Assay used (important for comparison

between labs)

Dairycare, Bern, E. Möstl 2015 35

Reference substance like creatinine?

Influence of food/mikroorganisms on

faecal glucocorticoid metabolites in

dairy cows

?

Biological sensitivity of the test is important! Using a corticosterone assay for measuring

glucocorticoid metabolites in faeces of cows?

References of our group related to faecal

glucocorticoid metabolites

Reviews

Möstl, E., Palme, R. (2002): Hormones as indicators of stress. Dom. Anim. Endocrinol. 23, 67-74.

(pdf)

Möstl, E., Rettenbacher, S., Palme, R. (2005): Measurement of corticosterone metabolites in

birds’ droppings: An analytical approach. Annals New York Acad. Sci. 1046, 17-34. (pdf)

Palme, R. (2005): Measuring fecal steroids: Guidelines for practical application. Annals New York

Acad. Sci. 1046, 75-80. (pdf)

Palme, R. (2012): Monitoring stress hormone metabolites as a useful, non-invasive tool for welfare

assessment in farm animals. Animal Welfare 21, 331-337. (pdf)

Palme, R., Rettenbacher, S., Touma, C., El-Bahr, SM., Möstl, E. (2005): Stress hormones in

mammals and birds: Comparative aspects regarding metabolism, excretion and noninvasive

measurement in fecal samples. Trends in Comparative Endocrinology and Neurobiology. Annals

New York Acad. Sci. 1040, 162-171. (pdf)

Palme, R., Touma, C., Arias, N., Dominchin, MF., Lepschy, M. (2013): Steroid extraction: Get the

best out of faecal samples. Wiener Tierärztl. Mschrift – Vet. Med. Austria 100, 238-246. (pdf)

Sheriff, MJ., Dantzer, B., Delehanty, B., Palme, R., Boonstra, R. (2011): Measuring stress in

wildlife: techniques for quantifying glucocorticoids. Oecologia 166, 869-887. (pdf)

Touma, C., Palme, R. (2005): Measuring fecal glucocorticoid metabolites in mammals and birds:

The importance of validation. Annals New York Acad. Sci. 1046, 54-74. (pdf)

Dairycare, Bern E. Möstl 2015 36

Ruminants

Arias, N., Requena, M., Palme, R. (2013): Measuring faecal glucocorticoid metabolites as a non-

invasive tool for monitoring adrenocortical activity in South American camelids. Anim. Welfare 22,

25-31. (pdf)

Belo, CJ., Schlegel, S., Moll, J., Möstl, E., Bruckmaier, RM. (2009): Milk ejection disorders in

Swiss dairy cows: a field study. J. Dairy Res. 76, 222-228. (pdf)

Bertulat, S., Fischer-Tenhagen, C., Suthar, V., Möstl, E., Isaka, N., Heuwieser, W. (2013):

Measurement of fecal glucocorticoid metabolites and evaluation of udder characteristics to

estimate stress after sudden dry-off in dairy cows with different milk yields. J. Dairy Sci. 96, 3774-

3787. (pdf)

Corlatti, L., Béthaz, S., von Hardenberg, A., Bassano, B., Palme, R., Lovari, S. (2012): Hormones,

parasites and male reproductive tactics in Alpine chamois: identifying the mechanisms of life

history trade-offs. Anim. Beh. 84, 1061-1070. (pdf)

Corlatti, L., Palme, R., Frey-Ross, F., Hackländer, K. (2011): Climatic cues and glucocorticoids in

a free-ranging riparian population of red deer. Folia Zool. 60, 176-180. (pdf)

Dehnhard, M., Clauss, M., Lechner-Doll, M., Meyer, HHD., Palme, R. (2001): Non-invasive

monitoring of adrenocortical activity in the roe deer (Capreolus capreolus) by measurement of

fecal cortisol metabolites. Gen. Comp. Endocrinol. 123, 111-120. (pdf)

El-Bahr, SM., Möstl, E., Palme, R. (2003): Glucocorticoid metabolites inhibit the metabolism of

androstendione in red blood cells of ruminants. J. Vet. Med. A 50, 98-102. (pdf)

Dairycare, Bern E. Möstl 2015 37

Ruminants

Huber, S., Palme, R., Arnold, W. (2003) Effects of season, sex, and sample collection on

concentrations of fecal cortisol metabolites in red deer (Cervus elaphus). Gen. Comp. Endocrinol.

130, 48-54. (pdf)

Huber, S., Palme, R., Zenker, W., Möstl, E. (2003): Non-invasive monitoring of the adrenocortical

response in red deer. J. Wildlife Managment 67, 258-266. (pdf)

Kleinsasser, C., Graml, C., Klobetz-Rassam, E., Barth, K., Waiblinger, S., Palme, R. (2010):

Physiological validation of a non-invasive method for measuring adrenocortical activity in goats.

Wiener Tierärztl. Mschr. – Vet. Med. Austria 97, 259-262. (pdf)

Konjević, D., Janicki, Z., Slavica, A., Severin, K., Krapinec, K., Božić, F., Palme, R. (2011): Non-

invasive monitoring of adrenocortical activity in free-ranging fallow deer (Dama dama L.). Eur. J.

Wildlife Res. 57, 77-81. (pdf)

Lexen, E., El-Bahr, SM., Sommerfeld-Stur, I., Palme, R., Möstl, E. (2008): Monitoring the

adrenocortical response to disturbances in sheep by measuring glucocorticoid metabolites in the

faeces. Wien. Tierärztl. Mschr. - Vet. Med. Austria 95, 64-71. (pdf)

Lexer, D., Hagen, K., Palme, R., Troxler, J., Waiblinger, S. (2009): Time budgets and

adrenocortical activity of cows milked in a robot or a milking parlour: inter-relationships and

influence of social rank. Animal Welfare 18, 73-80. (pdf)

Montanholi, YR., Swanson, KC., Palme, R., Schenkel, FS., McBride, BW., Lu, D., Miller, SP:

(2010): Assessing feed efficiency in beef steers through feeding behavior, infrared thermography

and glucocorticoids. Animal 4, 692-701. (pdf)

Dairycare, Bern E. Möstl 2015 38

Ruminants

Nordmann, E., Keil, NM., Schmied-Wagner, C., Graml, C., Langbein, J., Aschwanden, J., von Hof,

J., Maschat, K., Palme, R., Waiblinger, S. (2011): Feed barrier design affects behaviour and

physiology in goats. Appl. Anim. Beh. Sci. 133, 40-53. (pdf)

Palme, R., Fischer, P., Schildorfer, H., Ismail, M.N. (1996): Excretion of infused 14C-steroid

hormones via faeces and urine in domestic livestock. Anim. Reprod. Sci. 43, 43-63. (pdf)

Palme, R., Möstl, E. (1997): Measurement of cortisol metabolites in faeces of sheep as a

parameter of cortisol concentration in blood. Z. Saugetierkd. – Int. J. Mammal. Biol. 62, 192-197,

Suppl. 2. (pdf)

Palme, R., Robia, C., Baumgartner, W., Möstl, E. (2000): Transport stress in cattle as reflected by

an increase in faecal cortisol metabolites. Vet. Rec. 146, 108-109. (pdf)

Palme, R., Robia, Ch., Messmann, S., Hofer, J., Möstl, E. (1999): Measurement of faecal cortisol

metabolites in ruminants: A non-invasive parameter of adrenocortical function. Wien. Tierärztl.

Mschr. 86, 237-241. (pdf)

Patt, A., Gygax, L., Wechsler, B., Hillmann, E., Palme, R., Keil, NM. (2012): The introduction of

individual goats into small established groups has serious negative effects on the introduced goat

but not on resident goats. Appl. Anim. Beh. Sci. 138, 47-59. (pdf)

Patt, A., Gygax, L., Wechsler, B., Hillmann, E., Palme, R., Keil, NM. (2013): Factors influencing

the welfare of goats in small established groups during the separation and reintegration of

individuals. Appl. Anim. Beh. Sci. 144, 63-72. (pdf)

Dairycare, Bern E. Möstl 2015 39

Ruminants

Patt, A., Gygax, L., Wechsler, B., Hillmann, E., Palme, R., Keil, NM. (2013): Behavioural and

physiological reactions of goats confronted with an unfamiliar group either alone or together with

two peers. Appl. Anim. Beh. Sci. 146, 56-65. (pdf)

Pesenhofer, G., Palme, R., Pesenhofer, RM., Kofler, J. (2006): Comparison of two methods of

fixation during functional claw trimming - walk-in crush versus tilt table - in dairy cows using faecal

cortisol metabolite concentrations and daily milk yield as parameters. Wien. Tierärztl. Mschr. - Vet.

Med. Austria 93, 288-294. (pdf)

Rouha-Mülleder, C., Palme, R., Waiblinger, S. (2010): Assessment of animal welfare in 80 dairy

cow herds in cubicle housing – animal health and other animal-related parameters (German,

English abstract). Wien. Tierärztl. Mschr. – Vet. Med. Austria 97, 231-241. (pdf)

Sauerwein, H., Müller, U., Brüssel, H., Lutz, W., Möstl, E. (2004): Establishing baseline values of

parameters potentially indicative of chronic stress in red deer (Cervus elaphus) from different

habitats in western Germany. Eur. J. Wildlife Res. 50, 168-172. (pdf)

Sid-Ahmed, O., Arias, N., Palme, R., Möstl, E. (2013): Increased immunoreactive 11-

ketotestosterone concentrations in sheep feces after ACTH challenge. Environ. Toxicol. Chem.

32, 1332-1336. (pdf)

Sid-Ahmed, OE., Sanhouri, A., Elwaseela, BE., Fadllalah, I., Mohammed, GEE., Möstl, E. (2013):

Assessment of adrenocortical activity by non-invasive measurement of faecal cortisol metabolites

in dromedary (Camelus dromedarius). Trop. Anim. Health Prod. 45, 1453-1458. (pdf)

Dairycare, Bern E. Möstl 2015 40

Ruminants

Szabò, S., Barth, K., Graml, C., Futschik, A., Palme, R., Waiblinger, S. (2013): Introducing young

dairy goats into the adult herd after parturition reduces social stress. J. Dairy Sci. 96, 4644-4655.

(pdf)

Wagner, K., Barth, K., Palme, R., Futschik, A., Waiblinger, S. (2012): Integration into the dairy

cow herd: long term effects of mother contact during the first twelve weeks of life. Appl. Anim.

Beh. Sci. 141, 117-129. (pdf)

Weiss, D., Helmreich,. Möstl, E., Dzidic, A., Bruckmaier, RM. (2004): Coping capacity of dairy

cows during the change from conventional to automatic milking. J. Anim. Sci. 82, 563-570. (pdf)

Weiss, D., Möstl, E., Bruckmaier, RM. (2005): Physiological and behavioural effects of

changeover from conventional to automatic milking in dairy cows with and without previous

experience. Vet. Med. Czech 50, 253-261. (pdf)

Dairycare, Bern E. Möstl 2015 41

Dairycare, Bern, E. Möstl 2015 42

The skin has an equivalent of the

HPA-axis

Hair cycle of the species has to

be considered

Contamination of skin (social

licking, excreta)

Cortisol or cortison or

corticosterone?

UV-light

Cortisol is also produced in the

thymus, the skin and the intestine

Matrices

Dairycare, Bern E. Möstl 2015 43

Blood: invasive, episodic pattern can be followed

Saliva: less invasive, episodic pattern can be followed

Urine: non invasive, but not easy to collect, episodic pattern can not be followed

Faeces: non invasive, easy to collect, episodic pattern can not be followed

Hair: episodic pattern can not be followed, no chronologically assignment for

a short term stressor

Dairycare, Bern, E. Möstl 2015 44

Cortisol metabolites are inactive?

H 3CO H

H 3C

O

H 3CO H

H 3C

O

H 3CO H

H 3C

O

H 3CO H

H 3C

O

Testosterone DHT

Some cortisol metabolites are active substances 5 a-reduced glucocorticoids: a story of natural selection

Nixon et al., 2012, J. Endocrinol.212, 111-27

Androgens in vertebrates

Amphibien

O

O

O

OHO

OH

O

OH

O

+

Fish

Lamprey

Reptiles

Birds

Mammals Amphibians

Cows faeces show androgenic activity (Riley and

Hammond, 1942 Endocrinology, 31 Dairycare, Bern, E. Möstl 2015 45

Sid-Ahmed et al (2013): Increased immunoreactive 11-ketotestosterone

concentrations in sheep feces after ACTH challenge.

Environ. Toxicol. Chem. 32, 1332-1336. (pdf)

Results

♀

♂ Fin tubercles

Abb: Egami (1975)

5α-Androstan-

3,11,17-trion

11-Keto-

testosterone

Tren. Östr. Lsgm.

male phenotype (%)

Concentrations in tank water (µg/l)

NK

♀

♂

Abb: Egami (1975)

100

50

00,1 0,11 110 10100 100

Grillitsch et al., (2010) Environmental Toxicology and Chemistry 29, 1613-20

Dairycare, Bern, E. Möstl 2015 46

What about the 5ß-androstane

metabolites?

Dairycare, Bern, E. Möstl 2015 47

(Credit: iStockphoto/Dave Brenner)

In humans, etiocholanolone causes fever (Experimental etiocholanolone fever. Schulman et al., 1964, JCEM)

11-oxoetiocholanolone is

a pheromone in the round

goby

I hope I convinced you that:

Glucocorticoids are „anti-stress“ hormones and

are not inherently bad

Glucocorticoids are excreted as metabolites and

the concentration of those substances is a good

parameter for glucocorticoid production

Some glucocorticoid metabolites are

biologically active substances

48

Validity and biological sensitivity of the

assay are implicit presuppositions for

non-invasive monitoring!!

Future

Role of microorganisms and interaction with diet. Are

different diets causing different metabolism of steroid

hormones?

Digestive tract and its role in the metabolome of

vertebrates.

Analytical aspects: 1) High throughput analysis

2) HPLC-MS/MS

Dairycare, Bern, E. Möstl 2015 49

Dairycare, Bern E. Möstl 2015 50

Catecholamine metabolism Is it hopeless to find a long term surrogate parameter for catecholamine production?

Catecholamines are mainly

excreted via the urine as

shown

by radiometabolism

studies.

2%

98%

Days after administration

0 7 14 21 28

0

30

60

90

kB

q/l p

lasm

a

El-Bahr et al., 2006, Vet. Res Comun. 30, 423-32

Those radioactive substances are of high moleculat weight

(adducts of catecholamines to proteins)

Dairycare, Bern, E. Möstl 2015 51

Catecholamines form adducts

Catecholamines form adducts with thiol- or amino-groups.

Catecholamines are therefore incorporated in proteins.

The half-life of these adducts is much longer than that of the catecholamine itself.

Epinephrine

OH

HNCH3

HO

HCOH

CH2

5-Cystein-S-yl-epinephrine

S NH2

COOH OH

HNCH3

HO

HCOH

CH2

Research group

„Stress“

52 Dairycare, Bern, E. Möstl 2015 52