ANDROGENIC PROGESTOGENS OPPOSE THE DECREASE OF INSULIN-LIKE GROWTH-FACTOR-I SERUM LEVEL INDUCED BY CONJUGATED ESTROGENS IN POSTMENOPAUSAL WOMEN - PRELIMINARY-REPORT

Oral oestrogen treatment in postmenopausal women causes a decrease of insulin-like growth factor I (IGF-I) serum level, probably through a h epatocellular effect. To explore the possibility that the androgenic p rogestogens oppose this effect, serum IGF-I and sex hormone binding gl obulin (SHBG) were evaluated in two groups of patients treated respect ively with oral conjugated oestrogens (oCE) or transdermal oestradiol (tdE(2)), in a first phase with the addition of dydrogesterone (DYDR), a non-androgenic progestogen, and subsequently with the addition of n orethisterone acetate (NETA). With respect to basal values, treatment with oCE + DYDR caused an increase of SHBG (P < 0.002) and a decrease of IGF-I serum levels (P < 0.05); the shift to NETA addition opposed b oth effects: SHBG levels decreased partially but significantly (P < 0. 01 vs. oCE + DYDR) and IGF-I returned to basal values with a significa nt increase with respect to the oCE + DYDR phase (P < 0.02). No change s were observed in the tdE, + DYDR treated women; in this group the sh ift to NETA addition caused a significant decrease of SHBG values (P < 0.001 vs. before treatment and vs. tdE, + DYDR phase) and a slight in crease of IGF-I values. These differential effects on IGF-I and SHBG s erum levels might be relevant as far as breast cancer risk is concerne d.