Feb 15, 1990 - medications or had a history of endocrine disorders. The ... 11/780, Digital Equipment Corporation, Maynard, MA) system which allowed ...
N effects
The
high
of
intensity cycle
exercise on
Kraemer,
Charles J.
Hannan, Thomas Kettler,
Joseph E.
Dziados,
A.
John F.
response patterns
William J.
Everett
DTIC
un L E C T E 'u- FEB 15 1990
1%
sympath-adrenal-medullary
(
COX
~FIc1LE.
Andrew C.
Patton, Howard G. Scott
E.
Fry, Peter N.
SD
Knuttgen,"
'N-
Gordon,.. Frykman, and
Harman
) Exercise Physiology Division, U.S. Environmental
Army Research
Investigation, Madigan Army Medical
WA
and Center for
98431
Sports Medicine,
University, University Park, PA
Running Head:
Department
Medicine, Natick, MA 01760-5007,
Clinical
Peptide F
responses
of
Center, Tacoma,
The Pennsylvania State
16802
to high
Institute of
U.S.A.
intensity cycle
exercise
Address
(
Correspondence
Approved for public rees
Distnbution Lnimjted -_
-,
to:
William J.
Kraemer,
Center
Sports Medicine
for
Ph.D.
Greenberg Sports
Complex
The Pennsylvania
State University
University
Park,
'".r. ; .
PA
16802
.
2 ABSTRACT
PPlasma proenkephalin Peptide F immunoreactivity (ir)
and
catecholamines were examined before and after maximal exercise to exhaustion at four
intensities [36,
55, 73 and 100% maximal
leg
power (MLP)] by means of a high resistance cycle ergometer.
All
intensities were greater than those eliciting peak O2 uptake for the individual subjects.
Blood samples were obtained immediately
after exercise and at 5 and 15 min post-exercise.1 (p < 0.05)
Significant
increases in plasma Peptide F ir were observed
immediately following exercise at 36% MLP.
Significant
increases
in plasma epinephrine were observed immediately following exercise at 36% 100% MLP.
and 55% MLP and at 15 min following exercise at
Significant increases for plasma norepinephrine were
observed immediately following exercise (36, MLP),
55, 73,
and 100%
5 min after exercise (36, 55, and 73% MLP) and 15 min
following exercise (36% MLP).
Increases in whole blood lactate
were observed at all points post-exercise for 36,
55, and 73% MLP
and at 5 min post-exercise for 100% MLP exercise intensity. These data show that brief, high intensity exercise results in differential response patterns of catecholamines and proenkephalin Peptide F ir.
A These data suggest that exercise-
or
induced increases may be the result of non-colinear storage and
Il
3 release mechanisms
in the adrenal medulla.
:td
K1ey Words: proenkephalins, opioid peptides, epinephrine, norepinephrine, anaerobic exercise, skeletal muscle morphology 4 Dist
0 0
bility Codes acidor
Special
3
Many studies intensities
have demonstrated that
ranging from submaximal
endurance exercise at
to peak 02 uptake stimulates
the sympatho-adrenal-medullary system as evidenced by increases in plasma catecholamines (10,13,17,19,21,28,29,31,33,36). clear,
however,
Less
are the exercise-induced responses of
preproenkephalin peptides found in the adrenal-medullary chromaffin cells which have been shown to be responsive same stimuli examining (i.e.
that
induce epinephrine
the smallest
to the
release (18,31,40).
Studies
preproenkephalin biosynthetic end-products
methionire-enkephalin and leucine-enkephalin)/have
typically demonstrated no significant increases above rest endurance exercise stress
(10,23).
after
Conversely, increases above
rest have been observed for larger preproenkephalin fragments (e.g. Peptide F)
consequent to graded exercise
While receiving greater attention, only
(24,25,27).
limited data concerning
the adrenal-medullary responses to short-term, high intensity exercise (greater than peak 02 uptake) are available. studies
have demonstrated significant
Previous
exercise-induced increases
in plasma epinephrine and norepinephrine following short-term exercise
tasks ranging
interval
runs
has ever
been made
peptide (i.e. intensities at
from a 20 sec sprint
(6,12,19,39).
Still,
to repetitive
to our knowledge, no attempt
to examine catecholamine and preproenkephalin
Peptide F)
responses to a wide range of
very high power outputs.
containing polypeptides (ECPs)
exercise
Since enkephalin-
are responsive to
the same stimuli
4 that
induce epinephrine secretion, it was hypothesized that ECPs
would be responsive to high primary purpose of alterations (107-140)]
intensity exercise stress.
this study was
of maximum.
the
to examine the plasma
of catecholamines and Peptide F at maximal
Thus,
[preproenkephalin-
power production and at various percentages
These data will
adrenal-medullary responses
enhance the understanding of to high-intensity exercise.
METHODS Subiects.
Nine normally active, healthy men provided written
informed consent prior
to
their participation.
All were
medically screened by a physician, and none were taking any medications or had a history of endocrine disorders. subjects' physical characteristics were
(mean ± 1SD):
± 4.0 yr;
height,
body
14.8 + 4.9; maximal 02 uptake (VO2nax),
fat,
178.5 + 5.0 cm;
The
weight,
78.9
7.3
+
age,
23.9
kg; percent
47.3 ± 7.7
ml'kg-l'min-l. Subjects were thoroughly familiarized with all equipment and procedures prior body density
(11,41)
to taking part.
and VO2max(7,
32
testing Measurements of
) were made approximately two
weeks before the determination of maximal These methods have beepcribedin
Muscle biopsy Procedures and analyses.
power production. detail (26).
To examine
the
relationships between skeletal muscle morphological characteristics and peripheral muscle biopsy samples
blood hormonal
concentrations,
were obtained approximately
10 days prior
5 to maximal
power
testing.
from the superficial the dominant
Muscle
tissue samples were obtained
portion of the vastus
lateralis muscle of
leg utilizing the percutaneous
needle biopsy
technique of Bergstrom (3) as modified by Evans et al. Special all
subjects
repeat and
care was
taken
to approximate
the same biopsy location in
using a depth of approximately 2 cm.
biopsies
(9).
Pafa from
(randomly performed) demonstrated nonsystematic
insignificant
interbiopsy variations
in fiber-type
?
distributions.
