Effect of angiotensin II on human luteinized granulosa cells

Objective: To determine if human luteinized granulosa cells (GCs) exhibit angiotensin II (AII) receptors and if AII affects GC steroidogenesis. Design: Luteinized GCs were either treated immediately or maintained in culture for up to 6 days before use. The presence of functional AII receptors was evaluated using the following criteria: [1] receptor binding of ¹²⁵I- labeled AII; [2] changes in inositol phosphate production; [3] effects on progesterone (P) production; and [4] effects on cyclic adenosine 3':5' monophosphate (cAMP) production. Results: No specific binding of ¹²⁵I- labeled AII was observed using human luteinized GCs in culture. Angiotensin II did not alter the formation of [³H] inositol phosphates, nor did it alter the release of P from freshly isolated cells or cells that had been in culture for 5 days. Angiotensin II was also unable to alter basal or gonadotropin-stimulated cAMP production. These data suggest that human luteinized GCs exhibit little or no type 1 or type 2 AII receptors. Conclusion: This observation is in contrast to reports in rat granulosa that exhibit AII receptors. The reason for a lack of AII receptor expression on human luteinized GCs is unknown but could be because of luteal phase down regulation with gonadotropin-releasing hormone agonist or the subsequent stimulation with gonadotropins in these women before follicular stimulation.