FATTY ACIDS AS REGULATORS OF CELL MEMBRANE FUNCTIONS 489 Table I. Amplitudes of the phoreographical response SRV (see text) in % of the subthreshold resistance. Animals are fed on a deficient diet for 28 days (period I) then transferred on control diet (period II) Days Animals on deficient diet Days Animals on control diet 6 rats 6 rats r • • mean 4- SD no. 1 no. 2 no. 3 no. 4 no. 5 no. 6 Mean 4-SD .• 7th 17 23 2 38 4 16 17 -½ 6 24 -½ 5 • 12th 3 12 2 2 4 3 4 4- 1.5 11 4- 0.5 '•'• 20th 2 0 0 0 2 2 1 4- 0.2 18 4- 0.5 m • 28th 0 0 0 0 0 0 0 15 4- 2 2nd 0 0 0 0 0 0 0 17 _-k 2 .. '• • • 3rd 10 20 5 0 8 10 12 4- 3.5 25 4- 3 •o '• 5th 20 20 12 16 12 dead 16 4- 3.5 23 4- 6 • 9th 14 12 18 14 10 ,, 13 4- 0.2 22 4- 6 17th 13 19 23 17 14 ,, 17 4- 0.5 26 4- 5 weeks, reached about 60}/0 of the initial value. On another hand, SSO dosage caused a dramatic increase in skin resistance values as these, after only 1 week, are more than double the initial values (see Fig. 2). Transepidermal water loss An increase in transepidermal water loss was observed which was very slow at the beginning of the experiment (no significant increase after 3 weeks), then became faster. Conversely, a sharp decrease occurred within 2 weeks of sunflower seed oil dosage until the transepidermal water loss returned to the initial value after 3 weeks (Table II). Table I[. Variation of transcutaneous water loss (TWL) in rats during EFA-deficiency and after returning to control diet (means of six measurements expressed in mg H,•O cm -a h 4, 4- SD) Start EFA-deficiency 1 week on normal 3 weeks 4 weeks 7 weeks diet Deficient Control 0.30 4- 0.1 0.80 4- 0.1 1.9 4- 0.30 2.8 4- 0.20 0.60 4- 0.30 0.30 4- 0.1 0.60 4- 0.1 0.80 4- 0.30 0.70 4- 0.10 0.60 4- 0.30

490 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 50 EFA deficiency ,, I I • I I I I 2 3 4 5 6 SSO dosoge 7 8 9 Weeks Figure 2. Simultaneous variations of (x) transepidermal water loss (TWL), (- - -) resistance at zero current and ( ) amplitude of the phoreographical response (SRV) expressed as percentages of the mean values obtained in control rats.