1067-4136/01/3204- $25.00 © 2001
Russian Journal of Ecology, Vol. 32, No. 4, 2001, pp. 272–276. Translated from Ekologiya, No. 4, 2001, pp. 297–302.
Original Russian Text Copyright © 2001 by Vershinin, Kamkina.
The biological characteristics of amphibians, which
develop in water (outside the mother’s organism) since
fertilization, determine their considerable dependence
on environmental conditions. Animals with various
morphological abnormalities are common in amphib-
ian populations (Borkin and Pikulik, 1986; Hebard and
Brunson, 1963; Talvi, 1993). The abnormalities are
often induced by byproducts of human activities, such
as various pollutants. All abnormalities may be divided
into two main groups: hereditary and acquired. The lat-
ter develop in the course of regeneration or ontogeny.
The abnormalities resulting from developmental distur-
bances and atypical regeneration are largely deter-
mined by pollutant-induced inhibition or activation of
the thyroid function. This leads to the suppression of
proliferation and morphogenesis during larval develop-
ment and organ regeneration (Syuzyumova, 1985) and
affects the metabolic rate (Tokar’
Cytological parameters reﬂect the physiological
state of the organism and result from its interaction
with the environment. Tissue mitotic activity is an indi-
cator of the organism’s general activity and physiolog-
ical state (Sokolov and Kuznetsov, 1978). The species
and geographic speciﬁcity of mitotic activity in
amphibians is known (Gatiyatullina, 1978). Effects of
hormones, especially thyroid hormones, on mitotic
activity have also been studied (Dournon and Chibon,
Amphibian development, including metamorphosis,
is an ordered sequence of events. This sequence is
partly determined by a gradual increase in the activity
of the thyroid and sensitivity of different systems to the
hormones secreted by it. Morphogenesis and regenera-
tion are mainly governed by the pituitary–thyroid axis
(Fischman, 1996; Menon
, 1996). Thyroid hor-
mones are mainly catabolized in the liver and kidneys.
In homoiotherms, thyroxin has a calorigenic effect
related to an increase in oxygen consumption by most
tissues. Poikilotherms are insensitive to the calorigenic
effect of thyroid hormones (Gorbman and Bern, 1962).
Administration of thyroid hormones to tadpoles of var-
ious amphibians (before metamorphosis) does not
affect oxygen consumption. However, thyroid hor-
mones substantially increase oxygen consumption in
(Warren, 1940); if the animals are
kept at a temperature of
or higher, the their body
Metabolic rate may be estimated directly, using
physiological methods (based on oxygen consump-
tion), or indirectly, using either morphophysiological
methods (by determining the liver index) or cytological
methods (by analyzing tissue mitotic activity).
We attempted to apply estimation of tissue prolifer-
ative activity, along with some other parameters, to eco-
logical studies on the speciﬁcity of population pro-
cesses in the recent biota. This makes it possible to esti-
mate the signiﬁcance of changes at the cell level in
amphibians from populations exposed to different
types of anthropogenic impact.
Proliferative Activity of Corneal Epithelium
and Specific Features of Morphogenesis in Postmetamorphic
Nilss. in Urbanized Areas
V. L. Vershinin and I. N. Kamkina
Institute of Plant and Animal Ecology, Ural Division, Russian Academy of Sciences,
ul. Vos’mogo Marta 202, Yekaterinburg, 620144 Russia
Received August 29, 1999
—The mitotic activity and sizes of corneal epithelial cells in postmetamorphic
studied in the populations exposed to different degrees of anthropogenic impact in the city of Yekaterinburg.
The studies were conducted at the initial stages of frogs’ terrestrial life in three consecutive years. Mitotic activ-
ity exhibited a slight positive correlation with the liver index, which indirectly reﬂects the general metabolic
rate in young frogs. The combined estimation of proliferative activity, epithelial cell size, and relative liver
weight had the highest information value. There was a relationship between the mitotic index and liver index
in young frogs from habitats with the highest level of anthropogenic transformation. This indicates that mor-
phogenesis is well-balanced and is likely to decrease the probability of morphological abnormalities in frogs
developing in the unstable environment. This physiological property allows the populations to exist and repro-
duce in urbanized areas.
, proliferative activity, morphophysiology, morphogenesis.