Human Reproduction vol.9 no.8 pp.1448-1451. 1994 Somatostatin in human foUicular fluid N.Holst1-4, E.Haug3, T.Tanbo1, T.Abyholm1 and

4To whom correspondence should be addressed To demonstrate the presence of somatostatin in human pre-ovulatory foUicular fluid, and to assess the role of this peptide in foUicular maturation, a total of 66 foUicular fluid samples were obtained from 26 patients at the time of oocyte recovery for in-vitro fertilization. FoUicular fluid concentrations of somatostatin, oestradiol, progesterone and androstenedione were measured by immunoassays. Somatostatin concentra-tions in concomitantly obtained plasma samples were also analysed. FoUicular fluid somatostatin concentrations ranged from undetectable (< 1.5 pmol/1) to 109.4 pmol/1. The mean ± SE somatostatin concentrations in foUicular fluid (12.8 ± 1.8 pmol/1) were significantly (P < 0.0001) increased compared to corresponding plasma concentrations of somatostatin (6.5 ± 0.2 pmol/1). A significant and positive correlation existed between foUicular fluid and plasma somatostatin concentrations (r = 0.27; P < 0.03). No differences in either foUicular fluid or plasma somatostatin concentrations were found between different stimulation protocols or diagnostic groups. Neither did foUicular fluid somatostatin concentration vary with foUicular size. Similarly, no differences in somatostatin concentrations were found between foUicular fluids associated with fertilized (13.2 ± 2. 1 pmol/1) or non-fertilized oocytes (10.5 ± 1.6 pmol/1). FoUicular fluid concentrations of somatostatin correlated positively with those of progesterone (r = 0.30; P = < 0.04), but not with those of oestradiol or androstenedione or with the androstenedione/oestradiol ratio. The relationship between foUicular fluid somatostatin and progesterone concentrations suggests that foUicular fluid somatostatin may have a physiological role in foUicular maturation and the luteinization process. Key words: foUicular fluid/in-vitro fertilization/progesterone/ somatostati