The corpus luteum (CL) is a transient endocrine organ that secretes progesterone to support early pregnancy. Using in situ hybridization, immunohistochemistry and computer imaging analysis, we have investigated the expression of transforming growth factor beta 1(TGF-beta 1) , its receptors, type I (TbetaR-I) and type II (TbetaR-II) as well as steroidogenic acute regulatory protein (StAR) in the corpus luteum (CL) of the rhesus monkey at various stages of CL development. The CL was induced by injection of pregnant mare serum gonadotropin (PMSG)/human chorionic gonadotropin (hCG). The expression of TGF-beta 1, TbetaR-I and TbetaR-II as well as StAR was detected in the CL in a time-dependent manner, reaching the maximum levels on D10 (functional stage), and decreased on Day 18 (regression stage). Injection of interferon-gamma (IFN-gamma) or tumor necrosis factor-alpha (TNF-alpha) at the functional stage of CL development significantly decreased the expression of StAR, as well as TGF-beta 1, and its receptors TbetaR-I and TbetaR-II. Our results suggest that TGF-beta 1 and its receptors may play an important regulatory role in maintaining CL function, and that IFN-gamma or TNF-alpha is capable of inhibiting their expression in the CL.
Animals Corpus Luteum