Endocrine Abstracts

Little is know about the effects of IGFs on the early preantral stages of follicle development. The aim of this study was to investigate the effects of IGF-I on recruitment and survival of human preantral follicles in vitro. Small ovarian cortical biopsies were obtained at laparoscopy, with informed consent and local ethical committee approval, from 27 premenopausal women. The tissue was divided and randomly allocated to 5 conditions. The first piece was fixed immediately as a control and the others were cultured for 7 days with or without IGF-1 (1-100 nanogram per millilitre). The culture was carried out on plate inserts using Matrigel or growth-factor reduced Matrigel (GFR-Mat). After 7 days the tissue was fixed, serially sectioned and stained with haematoxylin and eosin. The health (atretic or non-atretic) and stage of development of follicles were assessed microscopically. The percentage of atretic follicles increased in culture and was unaffected by the type of Matrigel or the addition of IGF-1. After 7 days in culture supported by Matrigel, 75 percent of healthy follicles had initiated growth (were at the primary stage or beyond) whereas in GFR-Mat, the proportions of primordial (49 percent) and early growing (51percent) follicles were similar to those in control (non-cultured) pieces (58 and 42 percent). In GFR-Mat, IGF-1, even at the lowest dose, increased the proportion of growing follicles from 51 percent to 89 percent (p < 0.005, Chi-square). There was no additional effect of higher doses of IGF-1.

In summary, these data show that the use of GFR-Matrigel provides a culture system that is ideally suited to the study of the effects of endogenous growth factors. IGF-1 is highly effective in stimulating growth of follicles from the primordial pool and it may be an important factor in the initiation of follicle growth in the human ovary. This work was supported by Wellbeing and the MRC.