الفهرس 
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Abstract
Aim: Endogenous estradiol is required for the normal cellular growth of
the kidney and maintenance of its function. In this study, an animal model
of menopause, bilateral ovariectomy, was used to evaluate the influence of
the exogenous estradiol on kidney functions in female rats.
Methods: Fifty mature female Sprague-Dawley albino rats 3 months old
and 110-160 g body weight were used. The rats were fed on casein- based
diet. After acclimation, forty females were subjected to bilateral
ovariectomy under effect of ketamine and xylazine at doses (ketamine 80
mg /kg i.p, xylazine 10 mg/kg i.p), respectively. Sham operation was
performed on another ten female rats. 21 days after ovariectomy, the rats
were randomly divided into four groups in addition to sham operated group
(ten for each group).
group I, n=10, sham operated rats which received daily corn oil only
subcutaneously for 2 months. group II, n =10, they were ovariectomized
rats, received daily corn oil only subcutaneously for 2 months. group III,
n= 10, were ovariectomized rats which received daily 25µg /kg estradiol
benzoate (EB) subcutaneously in the form of Folone in corn oil (1: 50
V/V). group IV, n=10, were ovariectomized rats which received daily
50µg /kg EB subcutaneously in the form of Folone in corn oil (1: 50 V/V).
group V, n=10, were ovariectomized rats which received daily 100µg /kg
EB subcutaneously in the form of Folone in corn oil (1: 50 V/V). The
treatment continued for 2 months. The following parameters were
measured; food consumption, weight gain, relative kidneys weight,
glomerular filtration rate (GFR), urine volume, urine sodium (Na+
), urine
potassium (K+
), serum Na+
, serum K+
, renal malondialdehyde (MDA),
renal reduced glutathione (GSH), gene expression of aquaporin 2 (AQP2)
by RT-PCR as well as histopathology of renal tissue.
Results: The results showed that exogenous estrogen administration
significantly reduced food consumption, weight gain and, urine volume,
urine Na+, serum K+ and MDA. Also, it increased relative kidneys weight,
urine K+, serum Na+, GSH, AQP2 gene expression and GFR (improved
only after 2 months). Histopathological examination showed that E2
administration by the three doses revealed shrinkage of glomerulus,
hydropic degeneration of renal tubules, increased space of glomerulus and
congestion of inter-tubular blood capillaries especially after 2 months.
Conclusions: Administration of EB with 25 μg/kg dose was the best dose
that may mitigate ovariectomy induced renal dysfunctions but it doesn’t
reach the effect of physiological endogenous estrogen. However, the doses
50 and 100 μg/kg EB failed to reduce these dysfunctions especially at 2
months.