Effects of
Estradiol Benzoate and Progesterone on Superoxide
Dismutase Activity in the Thymus of Rats
J. KASAPOVIĆ, S.B. PAJOVIĆ, S. PEJIĆ, J.V.
MARTINOVIĆ
Laboratory
for Molecular Biology and Endocrinology, Vinča
Institute for Nuclear Sciences, Belgrade,
Yugoslavia
Received
February 21, 2000
Accepted May 26, 2000
Summary
The
activity of mitochondrial superoxide dismutase
(MnSOD) and cytosol superoxide dismutase
(CuZnSOD) was measured in corresponding
subcellular fractions prepared from the thymi of
intact and chronically gonadectomized (GX) rats
of both sexes, as well as of GX male and female
rats injected subcutaneously with a single dose
of 5 mg estradiol benzoate (EB) and/or 2 mg
progesterone (P). Animals were sacrificed 2 h or
24 h following hormone treatment. In the females,
the activity of MnSOD in the thymus was stable
during the estrous cycle and did not change after
ovariectomy. Treatment of GX females with
estradiol benzoate resulted 2 h later in a
significant elevation of MnSOD activity, whereas
24 h later the activity returned back to control
values. On the other hand, treatment of GX
females with progesterone had no effect on the
MnSOD activity. However, combined hormone
treatment, in which EB injection preceded
progesterone injection by one hour, enhanced the
effect on MnSOD activity similar to that of
estradiol benzoate alone. The activity of CuZnSOD
in cycling rats was increased in proestrus,
whereas removal of the ovaries kept the values at
low diestrus and estrus levels. Contrary to
MnSOD, CuZnSOD activity did not change after EB
treatment of GX females, while progesterone
increased the enzyme activity at 2 h and 24 h
after hormone treatment. However, combined EB+P
treatment proved to be ineffective. In the males,
neither MnSOD nor CuZnSOD activity was affected
by the removal of testes or by progesterone
treatment of GX animals. Only EB injection to GX
rats significantly increased CuZnSOD activity 24
h later.
Key
words
Superoxide dismutase · Thymus · Progesterone ·
Estradiol · Rats
Reprint
requests
Dr. Snežana B. Pajović, Laboratory for
Molecular Biology and Endocrinology, Vinča
Institute for Nuclear Sciences, P.O.Box 522,
11001, Belgrade, Yugoslavia. Fax.:
+38-1-11-455-561, e-mail pajovic@rt270.vin.bg.ac.yu
|