Effect of insulin (+/- Ins) on IGFBP-1 and IGFBP-2 secretion in steroid-treated ovariectomized baboons. Endometrial explants (n = 3) were obtained following steroid treatment and incubated in vitro. Media samples were analysed by western blotting for IGFBP-1 (A) and IGFBP-2 (B), and by ELISA for IGFBP-1 (C) after 24 h incubation. 14 d E: Treatment with estradiol for 14 days; 14 d E+P: Treatment with estradiol for 14 days followed by treatment with estradiol plus progesterone for 14 days; 14 d P: Treatment with estradiol for 14 days followed by treatment with progesterone alone for 14 days. These treatments represent the late follicular, mid secretory and late secretory stages of the cycle, respectively. Values above each band in A and B represent their optical density. Open bars: + Insulin; Closed bars: - Insulin.