Specificity of Gonadotropin Stimulation of Progesterone Synthesis in Bovine Corpus Luteumin Vitro

The effect of varying amounts of LH and FSH on progesterone biosynthesis was studied in vitro in bovine corpus luteum slices. It was found that a stimulatory effect could be obtained with amounts of LH as low as 0.01-0.02 μg/g of luteal tissue, or approximately 1×10-10M in the incubation medium. The stimulation was found to increase with increasing amounts of added LH. FSH (NIHFSH-S-1) was found to have about 1/100th the stimulating activity of LH, a value which correlates with its LH content as determined in the ascorbic acid depletion test of Parlow. Urea treatment of this FSH preparation markedly reduced its stimulatory activity on luteal progesterone synthesis. It was concluded that the stimulation of progesterone synthesis by FSH is due to its small LH content. On the basis of these and other data, it appears that, among the anterior pituitary hormones, LH alone stimulates steroidogenesis in the corpus luteum. (Endocrinology74: 664, 1964)