1062-3604/03/3405- $25.00 © 2003
Russian Journal of Developmental Biology, Vol. 34, No. 5, 2003, pp. 311–316. Translated from Ontogenez, Vol. 34, No. 5, 2003, pp. 371–376.
Original Russian Text Copyright © 2003 by Kirillov, Khasina, Durkina.
Chronic stress induced by various factors adversely
affects the postnatal growth of body weight in rats
, 1997; Haller
, 1999; Hu
, 2001). This phenomenon is largely
based on secretion of an increased amount of corticos-
terone by the adrenal glands, which has catabolic prop-
, 1993; Akana
Edward and Burnham, 2001). Under the conditions of
chronic stress, the corticosterone secretion undergoes
phase ﬂuctuations (Selye, 1960). However, the dynam-
ics of ratio between the postnatal growth of body
weight and adrenocortical activity in rats during the
entire cycle of stress development remains unknown.
The changes in postnatal growth of adrenal weight
in the stressed rats are, as a rule, not studied, probably,
because under the conditions of stress, adrenal glands
are hypertrophied. However, the zona fasciculata alone
is hypertrophied, while the weight of reticular zone
(androgenic system) decreases (Nussdorfer, 1986). It is
also assumed the postnatal growth of hypertrophied
zona fasciculata is delayed under the conditions of
long-term intense stress (Khasina
Here, we present the results of studying the postna-
tal growth of body and adrenal weights in the rats kept
under crowded conditions for a long time.
MATERIALS AND METHODS
Seven-week male Wistar rats weighing 145–155 g
were housed 10 (control) or 20 (crowded) per cage
15 cm). Groups of control and crowded ani-
mals were decapitated within 0.5, 1, 3, 7, 17, 21, 35, 56,
70, 84 and 98 days of experiment always at the same
time (9 to 10 a.m.) in order to exclude the changes
related to diurnal variation of the adrenal activity.
The adrenals, seminal vesicles, prostate, and testes
were removed and weighed. The plasma concentration
of corticosterone was measured in 10 rats of every
group (De Moor
, 1960) using an MF-2A spectrof-
luorimeter (Hitachi, Japan). The cholesterol content
was determined in the right adrenals (Engel’gard and
Smirnova, 1960). The left adrenals were ﬁxed by the
Carnoy’s ﬂuid and embedded in parafﬁn. Serial sec-
m thick, were made. Every tenth section was
glued to a slide and stained by hematoxylin and eosin.
The volume of adrenal cortex zones, volume of cells
and their nuclei, and number of cells in the zona fascic-
ulata were determined using the method of differential
point counting modiﬁed for the adrenal glands (Malen-
dowicz, 1987). The details of measurements were
described elsewhere (Kirillov, 1998).
The results we obtained were processed statistically
using the Student’s
RESULTS AND DISCUSSION
During the experiment, the body weight increased
2.2-fold (control) and 1.7-fold (experiment) (Fig. 1a).
The degree of divergence between the curves of postna-
tal growth of body weight in the experiment and control
progressed with the time of observation. The results we
obtained coincide with the published data on adverse
effect of crowding on the postnatal growth of body
weight in rats (Daniels-Severs
, 1973; Gamallo
PHYSIOLOGY OF DEVELOPMENT
Influence on Stress on Postnatal Growth of Body
and Adrenal Gland Weight in Rats
O. I. Kirillov, E. I. Khasina, and V. B. Durkina
Institute of Marine Biology, Far East Branch of the Russian Academy of Sciences,
ul. Pal’chevskogo 17, Vladivostok, 690041 Russia
Received July 28, 2000; in ﬁnal form, December 6, 2002
—Seven-week male Wistar rats weighing 145–155 g were housed 10 (control) or 20 (crowded) per
15 cm). Groups of control and crowded animals were decapitated within 0.5, 1, 3, 7, 14, 21,
28, 35, 56, 70, and 98 days of experiment. The keeping of rats in crowding conditions induced chronic stress,
which developed, according to phase changes in plasma concentration of corticosterone and adrenal content of
cholesterol, through the stages alarm, resistance, and exhaustion. The postnatal growth of body weight in the
stressed rats was behind that in the control. Under the crowding conditions, the adrenal weight did not undergo
signiﬁcant increase, since the stress-induced hypertrophy of the zona fasciculata was compensated by the pro-
portional suppression of the postnatal growth of the zona reticularis. After 56 days, the postnatal growth of the
hypertrophied fascicular zone was delayed in the experimental rats.
: crowding, postnatal growth of rats, chronic stress, androgenic system.