ADENYLYL-CYCLASE MESSENGER-RIBONUCLEIC-ACID IN MYOMETRIUM - SPLICE VARIANT OF TYPE-IV

Regulation of uterine tone during pregnancy and parturition involves G protein-coupled receptors that modulate cellular levels of cAMP. Cycl ic AMP is synthesized by a family of at least nine adenylyl cyclase en zymes that have unique tissue distributions, basal activities, and mod es of regulation. Little is known regarding the expression of adenylyl cyclase isoforms in myometrium. Reverse transcription-polymerase chai n reaction (PCR) was performed using RNA extracted from freshly dissec ted rat uteri and a cell line of homogenous rat myometrial cells. Usin g PCR primers specific for adenylyl cyclases I-IX, mRNA encoding adeny lyl cyclases Il-IX were identified an both fresh and cultured myometri al cells. A splice variant of adenylyl cyclase type IV was also identi fied in RNA from both sources. These data show that multiple isoforms of adenylyl cyclases are expressed at the mRNA level in myometrial cel ls and suggest that the regulation of cellular levels of cAMP likely i nvolves a complex integration of cellular second messengers acting upo n multiple isoforms of adenylyl cyclases.