Insulin-like Growth Factor 1 mRNA Expression in the Uterus of
Streptozotocin-treated Diabetic Mice |
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Authors: | Yoshie MANABE Makoto TOCHIGI Akiyoshi MORIWAKI Sakae TAKEUCHI Sumio TAKAHASHI |
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Institution: | 1)The Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan;2)Chugoku Gakuen University, Okayama 701-0197, Japan |
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Abstract: | Reproductive functions decline with the onset of diabetes in female mice. Diabetic mice
have smaller uteri with an underdeveloped endometrium, suggesting diminished
estrogen-induced growth. We aimed to clarify the changes in the estrous cycle and in
insulin-like growth factor 1 (IGF1) expression in the uteri of streptozotocin
(STZ)-treated diabetic mice, because IGF1 is one of the main growth factors involved in
estrogen-induced uterine growth. ICR female mice were intraperitoneally administered STZ
(10 mg/100 g BW), and blood glucose levels were determined. Mice with blood glucose levels
> 200 mg/dl were classified as diabetic mice. The onset of diabetes was associated with
acyclic estrous cycles. Diabetes was also induced with STZ in ovariectomized mice. Uterine
Igf1 mRNA levels were reduced in ovariectomized STZ-treated diabetic
mice. Estrogen is known to stimulate Igf1 mRNA expression in the uterus,
but estrogen action was abolished in the uteri of STZ-treated diabetic mice. mRNA
expressions of estrogen receptor α (ERα) and steroid hormone receptor coactivators
(SRC-1/Ncoa1, SRC-2/Ncoa2,
SRC-3/Ncoa3 and CBP/p300/Crebbp) were reduced in the
uteri of ovariectomized STZ-treated diabetic mice. The present study demonstrates that
diabetes induces a decline in female reproductive functions in mice. Igf1
expression in ovariectomized diabetic female mice was decreased, and decreased
responsiveness to estrogen in the uteri of diabetic mice is probably associated with a
reduction in ERα and steroid receptor coactivator mRNA expression. |
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Keywords: | Diabetes Insulin-like growth factor 1 (IGF1) Mouse Uterus |
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