Effects of Mammalian LH, Cyclic AMP and Phosphodiesterase Inhibitors on Steroidogenesis, Lactate Production, Glucose Uptake and Utilization by Avian Granulosa Cells1

Abstract

Granulosa cells isolated by collagenase digestion from the two largest preovulatory follicles of laying hens were incubated in Medium TC199. Progesterone and lactic acid concentrations were measured in the medium. Glucose utilization was estimated by the generation of [³H]₂O from D-[5-³H]glucose. Glucose uptake was assessed by determining the intracellular accumulation of 2-deoxy-D-[1-³H]glucose. At submaximally stimulating doses of oLH or bLH and dibutyryl cyclic AMP, theophylline and 3-isobutyl-1-methylxanthine (MIX) potentiated progesterone production, while at maximally stimulating doses of agonists both theophylline and MIX inhibited steroidogenesis. Moreover, LH-promoted steroidogenesis and lactic acid production was glucose dependent. Theophylline, MIX and papaverine significantly and in a dose-dependent fashion inhibited deoxyglucose uptake, glucose utilization and lactate production. It is concluded therefore that exogenous glucose is essential for LH-promoted steroidogenesis in isolated chicken granulosa cells. Moreover, phosphodiesterase (PDE) inhibitors suppress progesterone responses to optimally stimulating doses of LH and dibutyryl cyclic AMP by inhibiting glucose transport and utilization and not by influencing intracellular levels of cyclic AMP.