Comparison between Effects of Cyclic AMP, Dibutyryl Cyclic AMP and Luteinizing Hormone on Ovarian Glycolysis

Prepubertal rat ovaries were incubated in medium containing 5.5 mM glucose and various concentrations of cyclic AMP (cAMP) and dibutyryl cyclic AMP (dbcAMP). Glucose uptake and lactic acid production were stimulated in presence of 5 mM cAMP. The effect was less pronounced with higher concentrations, and 25 mM cAMP inhibited ovarian glycolysis compared to control ovaries. A biphasic effect was also obtained with dbcAMP: a dose‐dependent increase with lower concentrations (0.1–5 mM) and smaller effects with higher concentrations. Luteinizing hormone (LH) stimulates ovarian glycolysis with a linear dose‐response relationship over an extremely wide range of concentrations (Hamberger and Ahren 1967). The stimulatory actions of dbcAMP and LH on ovarian glycolysis were augmented by low concentrations of aminophylline (0.5‐1 mM). No additive effects were seen when LH and dbcAMP were used together in maximal stimulatory concentrations. LH, cAMP and dbcAMP were also compared as to their lipolytic actions on the ovary. Lipolysis as judged by glycerol release was markedly enhanced by dbcAMP while the two other substances had only marginal effects. When bovine serum albumin (acceptor for fatty acids) was present in the medium, the dose‐response curve of the effect of dbcAMP on ovarian glycolysis was dramatically changed, indicating an interaction between the lipolytic and the glycolytic effects of this compound.