Mary F. Cooper

Epidermal lipid metabolism in psoriasis and lichen simplex

The rate and pattern of epidermal lipogenesis from [14C] glucose were measured in fifteen patients with psoriasis and three with lichen simplex, compared with twenty controls. In ‘uninvolved’ epidermis from psoriatic subjects the mean lipogenic rate was slightly raised, although the increase was not statistically significant. There was a positive correlation between overall lipogenic rate and the percentage of isotope appearing in free sterol, while the relative proportions of the other lipid classes were unchanged. By contrast, in control epidermis sterol percentage was negatively correlated with lipogenic rate.

Sebaceous lipogenesis in human skin. Variability with age and with severity of acne.

Lipogenesis from [14C] glucose was measured in skin biopsies from the shoulder‐blade region of forty‐two male subjects. In the acne age range, dermal lipogenesis showed an upward trend with increasing severity of acne; a similar trend was found in forehead sebum excretion rate, but no correlation was obvious between dermal lipogenesis (back) and sebum excretion rate (forehead) in the same subject. In older subjects, dermal lipogenesis was significantly increased in those with a past history of severe acne.

Acquired ichthyosis and impaired dermal lipogenesis in Hodgkin's disease

Epidermal lipid biosynthesis was normal in patients with mild ichthyosis due to Hodgkins disease, but greatly reduced in one patient with severe ichthyosis. Dermal (sebaceous) lipid synthesis was decreased in all patients with Hodgkins disease, whether or not they had ichthyosis, and was greatly reduced in the patient with severe ichthyosis. Neither the mechanism nor the possible relationship between the dermal and epidermal changes is understood.

Hormonal regulation of cutaneous lipogenesis: Effects of hypophysectomy, posterior-hypophysectomy and α-melanocyte-stimulating hormone treatment

The effects of hypophysectomy, posterior-hypophysectomy and α-melanocyte-stimulating hormone on skin lipogenesis were studied in rat ear biopsies incubated in vitro with [U-14C] glucose. In skin from intact rats, 90% of the labelled lipid was present in the dermis and localised mainly in pilosebaceous units. The most heavily labelled lipids in dermis were the wax monoestersterol ester fraction and triglyceride; in epidermis relatively more isotope was incorporated into polar lipids and free sterols. Hypophysectomy reduced the labelling of all dermal lipids, the greatest changes occurring in the wax estersterol ester fractions and squalene. In contrast, epidermal labelling was slightly increased. Posterior-hypophysectomy reduced dermal labelling of sterols, free fatty acids, wax esters-sterol esters and squalene, but had little effect on polar lipids and appeared to increase the labelling of glycerides. In posterior-hypophysectomised rats a dose of 30 μg α-melanocyte-stimulating hormone/100 g body weight per day restored dermal wax ester biosynthesis to normal within 5 days.

Epidermal lipid biosynthesis in acne

Lipid biosynthesis from glucose was increased in severe acne both in dermis and in epidermis which included the top portions of the pilosebaceous follicles. Both tissues retained their characteristic lipid labelling pattern. The magnitude of the increase in dermis and epidermis was similar, suggesting that epidermis may be subject to the same sebotrophic‐lipogenic stimulus which affects sebaceous glands.