A. Ruiz et al., SERUM LEVELS OF GH, IGF-I, LH AND OVARIAN-STEROIDS IN CYCLIC AND RU486-TREATED RATS, Journal of endocrinological investigation, 20(10), 1997, pp. 611-615
Rats lacking progesterone action due to RU486 treatment have been repo
rted to show numerous endocrine and morphological similarities with re
spect to human polycystic ovary syndrome (PCO), Nevertheless, abnormal
ities on insulin or insulin-like growth factor I (IGF-I) production, a
frequent finding in the polycystic disease, have not been studied in
such rats yet, The aim of these experiments was to evaluate the serum
concentrations of IGF-I in rats treated with 4 mg of the antiprogestag
en RU486 over 4 or 8 consecutive days starting on estrus (day 1) and d
ecapitated on the morning of day 5 and 9, Serum levels of growth hormo
ne (GH), luteinizing hormone (LH), testosterone (T) and 17 beta estrad
iol (E-2) were determined and correlated with those of IGF-I, Controls
were rats injected with oil and killed in the morning of metestrus, d
iestrus, proestrus and estrus, Rats treated with RU486 had increased s
erum concentrations of IGF-I, LH, T and E-2 with respect to control ra
ts on estrus, while no differences were found in the serum concentrati
ons of GH, Parallel estrous cycle related changes were observed in the
serum concentrations of IGF-I, T and E-2 with the highest values at p
roestrus, However, changes on serum concentrations of GH were not asso
ciated with those of IGF-I in control rats through the estrous cycle,
The present results are consistent with the idea that beside on GH, se
rum concentrations of IGF-I in the rat depend also on LH or LH-depende
nt ovarian steroid production, Moreover, the results indicate that IGF
-I production increased in RU486-treated rats, which may have a role i
n the ovarian abnornalities induced by RU486 treatment in the rat. (C)
1997, Editrice Kurtis.