Exp Clin Endocrinol Diabetes 2013; 121 - P86
DOI: 10.1055/s-0033-1336773

Butyryl- and acetylcholine-esterases in human IVF-derived follicular fluid and luteinizing granulosa cells

J Blohberger 1, D Einwang 1, D Berg 2, U Berg 2, S Hecht 3, R Pavlik 3, C Thaler 3, S Saller 1, A Mayerhofer 1
  • 1University of Munich, Anatomy III – Cell Biology, Munich, Germany
  • 2A.R.T., Bogenhausen, Munich, Germany
  • 3University of Munich, Hormon und Kinderwunschzentrum, Department of Gynecology and Obstetrics, Munich, Germany

Background/objectives: Recent proteomic studies of human follicular fluid (FF) revealed the presence of the acetylcholine (ACh) degrading enzyme butyrylcholine-esterase (BChE). The presence of such an enzyme may be related to ACh, which is formed by human granulosa cells (GCs), and could restrict ACh-actions. ACh-actions include activation of muscarinic receptors of GCs, entailing changes in intracellular calcium, activation of transcription factors and ion channels, phosphorylation of the gap junction molecule connexin 43 and disruption of intercellular communication between GCs and proliferation. The cellular source of BChE in FF is not known. It is also unknown, if ACh-esterase (AChE), which has a variety of splice variants, is expressed in the ovary.

Methods/results: Activities of both enzymes (AChE and BChE) were detected in human FF, each accounting for about 60% of the overall activity. When FFs from women with polycystic ovary syndrome (n = 31) were compared to FFs from patients with male factor or unexplained infertility (n = 34), no apparent difference was observed.

In freshly isolated, IVF-derived GCs and in cultured human GCs AChE and BChE protein and mRNA were found. Hence, these enzymes are produced by luteinizing GCs. By using RT-PCR followed by sequencing, we were able to identify three AChE splice-variants: the read-through (R), the erythrocyte (E) and the synaptic (S) AChE variant. The R-AChE is of special interest because it has additional non-catalytic functions, which are related to the regulation of cell growth, differentiation and apoptosis, i.e. events of importance in follicular growth, atresia and ovulation. We are currently studying these issues.

Summary/conclusion: AChE and BChE are present in FF of the human pre-ovulatory follicle and luteinizing, IVF-derived GCs produce both enzymes. Whether the soluble R-AChE variant is active as a signaling molecule in the follicle remains to be shown.

(Supported by DFG MA1080/19 – 1).