The Effect of Hormones and their Analogues Upon the Uptake of Glucose by Mouse Skin in vitro

An experimental system is described for measuring the uptake of glucose by mouse skin in vitro. Insulin is found to stimulate and hydrocortisone to depress the glucose uptake of this system when added to the medium in concentrations comparable to those which may occur in vivo. Oestrogens, androgens and progestational agents, in contrast, have no effect at approximately physiological levels, but cause some depression of glucose uptake at high concentrations.

The effect of hydrocortisone on the response of fetal rat skin in culture to ultraviolet irradiation

1. The effect of hydrocortisone on the development of fetal rat skin in organ culture, and on its repair after exposure to a mixed beam from a mercury lamp, are described. 2. The addition of hydrocortisone (7.5 µg/ml) to the culture medium (HC medium) caused accelerated differentiation and keratinisation of the epidermis followed by atrophic changes as in vivo. 3. Explants were grown for 2 days in either normal or HC medium and then irradiated with light from an Hanovia lamp. 4. Irradiation of the control explants produced severe necrosis in both epidermis and dermis and much disorganisation of the dermal intercellular material; 2 days after exposure the s. corneum with adherent cellular debris had become either completely detached from the denuded dermis, or raised to form a fluid-filled blister. Epidermal regeneration had begun by the 4th day after irradiation and was usually complete by the 6th day. 5. Hydrocortisone modified the response to irradiation as follows: (1) reduced and retarded cellular breakdown, (2) prevented vesication, (3) preserved the organisation of the dermal intercellular material, (4) hastened epithelialisation, (5) accelerated the differentiation of the new epidermis. Effects (2), (3), and (4) were probably secondary to (1). 6. Experiments with various light filters showed that the effective wavelengths for producing lesions in the skin explants were those below 3000 A. 7. It is suggested that the beneficial effect of hydrocortisone on the repair of irradiated skin explants might be due, at least in part, to a reduced proteolytic activity in the damaged tissue through a stabilising action of the hormone on the lysosomes. 8. The relationship of these findings to clinical observations is discussed.

The effect of aminomethylpteroylglutamic acid on the development of skin hypersensitivity and on antibody formation in guinea pigs

1. In guinea pigs, aminomethylpteroylglutamic acid (methotrexate) is capable of blocking the development of delayed skin hypersensitivity, the primary antibody response, and the specific febrile response to ovalbumin and diphtheria toxoid. The primary antibody response is more easily inhibited than is the development of delayed skin hypersensitivity. 2. The effect of methotrexate on immunologic responses depended upon the dose of methotrexate employed and the strength of the antigenic stimulus.

Action of antidiuretic hormone on the equivalent pore radius at both surfaces of the epithelium of the isolated toad skin

A previously described method (1) allows the observation of swelling and shrinking of the epithelial cells of the isolated toad skin, when the solution bathing either the outer or inner side of the skin is modified. Thus, the concentration of probing molecules of graded size, isotonic to the epithelial cells, across each face of the isolated toad skin can be determined. These concentrations have been used for the estimation of the equivalent pore radius at the outer and inner face of the skin epithelium, following the approach of Goldstein and Solomon for red cells (3). An equivalent pore radius of 4.5 A for the outer surface, and one of 7 A for the inner surface have been obtained. Antidiuretic hormone had an effect only when added to the inner side. This effect was only at the outer surface and is interpreted as widening of the 4.5 A pores to about 6.5 A. A model membrane, formed by narrow and wide pores in series, may explain some of the apparent inconsistencies previously observed.

Angiotensin Skin Tests

The studies reported above indicate that the angiotensin skin test (A.S.T.) is a simple practical measure which has proved of value in differentiating between normotensive and hypertensive individuals. The duration of the blanching of skin by the test differs significantly in normotensives as compared with hypertensives. The test has served as an index [see figure in the PDF file] of differentiation between an emotionally induced elevation of blood pressure and one which may go on to an established hypertensive state. The A.S.T. is a more reliable test in the diagnosis of the latent, labile, or prehypertensive state than is the cold pressor test. Angiotensin-induced hypertension induces a prolongation of the A.S.T. as compared with control periods.