PROGESTERONE BIOSYNTHESIS IN LUTEAL TISSUE: ROLE OF NICOTINAMIDE ADENINE DINUCLEOTIDE PHOSPHATE AND NADP-LINKED DEHYDROGENASES.

The stimulation of luteal progesterone synthesis in vitro by pyridine nucleotide (NADPH) has been examined. Four NADP-linked dehydrogenases have been measured in bovine and human corpora lutea. Glucose-6-P, 6-P-gluconate, malate and isocitrate dehydrogenases were found in bovine corpora lutea in relatively high amounts, comparable to the respective concentrations seen in bovine adrenals. The 4 dehydrogenases appear to be capable of providing NADPH for the stimulation of synthesis in the luteal slice under in vitro incubation conditions, glucose-6-P and 6-P-gluconate dehydrogenases being the most effective. The stimulation of progesterone biosynthesis in vitro by exogenous NADP +glucose-6-P is usually greater than that caused by the addition of luteinizing hormone (LH).