Measurement of lipogenesis in isolated preputial gland cells of the rat and the effect of oestrogen.

Lipogenesis was measured in isolated preputial gland cells of female rats after ovariectomy and after the administration of oestradiol benzoate. Ovariectomy decreased preputial gland cell lipogenesis and also altered the pattern of lipid synthesis, producing a relative decrease in the proportion of polar lipids and an increase in the proportion of 'triglycerides'. Although daily administration of 2 or 10 micrograms oestradiol benzoate for 7 days produced slight increases in preputial gland cell lipogenesis in ovariectomized rats, the effects were not significant. A single injection of 10 micrograms oestradiol benzoate, however, produced significant increases in preputial gland cell lipogenesis of ovariectomized rats at both 2 and 24 h and, moreover, at 24 h the pattern of polar lipid and triglyceride labelling was restored to normal. Prior administration of actinomycin D reduced the lipogenic effect of oestradiol benzoate. Oestradiol benzoate had little or no effect on preputial gland cell lipogenesis in male rats. These results confirm that oestrogen is able to stimulate preputial lipogenesis in female rats. Whether this action of oestrogen is related to its pheromone-producing effect on the preputial glands is not yet known.