The somatostatin analogue, octreotide, modifies both steroidogenesis and IGFBP-1 secretion in human luteinizing granulosa cells.

The effect of the somatostatin analogue octreotide on the secretion of progesterone and insulin-like growth factor binding protein-1 (IGFBP-1) from human granulosa-luteal cells was investigated. Octreotide (10(-11), 10(-10) and 10(-9) M) alone induced a significant decrease in progesterone secretion (maximum suppression 69 +/- 5% of control: P < 0.0001). In contrast, treatment with octreotide in combination with human chorionic gonadotrophin (HCG), at 1 IU/ ml potentiated the stimulatory effect of HCG on progesterone secretion (HCG alone 201 +/- 3% of control: HCG + octreotide 10(-9) M 318 +/- 16%: P < 0.001). Treatment with octreotide increased the secretion of IGFBP-1 (maximum stimulation 254 +/- 25% of control: P < 0.01). No effect of HCG was seen on secretion of IGFBP-1. These findings raise the possibility that somatostatin may have a modulatory role in regulating steroidogenesis by the human corpus luteum. Further studies are required to establish the physiological significance of any such function.