The Effects of a Graded Series of Restricted Diets on Epidermal Mitotic Activity in the Mouse

Abstract

IT ha-s remntly been demonstrated that the most critical factor determining the epidermal mitosis rate in the adult mouse is the carbohvdrate supplv to the ceUs, and the evidence at present available aR points to the conclusion that the fimction of this carboh drate is to supplv the energy needed during ceR division y (BuRougb, 1949a(BuRougb, , 1950a. In extending this work the discoverv has been made that a restricted diet has a powerful effect in depressino, mitotic activitv (Bullough, 1949b), and it has been suggested that this observation mav help towards an explanation of Tannenbaum's remarkable results on the effects of restricted diets on tumourgenesis (Tannenbaum, 1940a(Tannenbaum, , 1940b(Tannenbaum, , 1942(Tannenbaum, , 194-4, 1945(Tannenbaum, , 1947 The two experiments performed involved a total of a-a-mice, which were aR adult males of between 3 and 5 months of age. In the first experiment the -95 animals included 10 Strong's CBA males and 15 K-reyberg's white label males. l[n the second experiment aR the animals were Strong's CBA males.These mice had been reared since weaning on a mixed diet of commercial rat cake with cod-hver oil, flaked maize, and dog biscuit, but during the experiments they were fed on commercial rat cake alone. They invariably received their food between 09.00 and 10-00 hours, so that they formed the habit of being awake and active at that time and of being asleep in the earlv afternoon. This determined the form of their diurnal cycle of mitotic activitv, and ensured that a high mitosis rate developed shortly after midda (BuRough. 1948). The experiments were carried out during the winter and earlv spring, and the ainimals were exposed to normal daybght. * Sorby Fellow of the Royal Society of London.

Thymidine uptake and cell migration in cheek epithelium of zinc‐deficient rats

“…Epidermal mitotic activity is sharply reduced when food intake is restricted to 75% of the ad lib. consumption and nearly ceases at restriction to 50% (Bullough & Eisa 1950). Pair-fed controls would in the last two weeks of the experiment have received little more than 50% of the ad lih.…”

Activation of antitumor properties in alveolar macrophages from protein-calorie malnourished rats

“…The discrepancy between the ability to express tumoricidal activity and impaired bactericidal activity of macrophages in protein-malnourished animals might explain why animals in a state of PCM are more resistant to the development of tumors [9-11, 20, 21, 31], but less resistant to a variety of pathogens [3,14,24]. Nevertheless, it is unlikely that the enhanced tumor resistance is due mainly to the fact that the AM have normal or even increased functional activity, since protein malnutrition may also have other effects related to tumor resistance such as reducing the amounts of essential nutrients available for tumor cell growth [1,4], inhibiting the carcinogenic process [12] and decreasing the level of serum tumor enhancing antibody [11].…”

The effect of ultra‐violet radiation and restricted diet on rat labial mucosa

“…Group B: The 12 rats of this group were restricted to a diet consisting of 50% by weight of the daily intake of the rats in Group A. This figure was arrived at on the basis of published data relating food intake to epithelial mitotic activity (BuUough & • Eisa 1950) and as a result of a pilot experiment in which a reduction of body weight and epithelial thickness was achieved after 4 weeks at this level. Nine randomly-selected rats of this group were subjected to ultra-violet radiation while the remaining three served as controls.…”