The role of blood glucose in activity related self-starvation

Abstract

Rats in the experimental group lived in activity wheels on a 23-h deprivation schedule, while those in the control group lived in laboratory cages on the same le ed i ng schedule. Blood-glucose determinations milde on the 1st, 3rd, and 6th days 01 deprivation indicated that, while both groups were hypoglycemic on Days 1 and 2, by Day 6 the experimental Ss were still hypoglycemic, while control Ss' blood-glucose levels approached normal ad lib levels. The results are in opposition to the hypo thesis 01 glucocorticoid involvement in activity-related selfstarvation. Routtenberg & Kuznesof (1967) reported that rats confined to activity wheels and placed on a 23-h food-deprivation schedule progressively lost weight yet dramatically increased their activity until starvation occurred. All control Ss, living on the deprivation schedule and in horne cages, were able to adapt and maintain weight. In addition, the experimental Ss ate significantly less than did controls. Routtenberg (1968) reported that adaptation to the deprivation schedule prior to introduction of the above conditions was successful in mitigating the self-starvation of experimental Ss. Leveille & O'Hea (1967) have shown that animals adapted to a 22-h food-deprivation cycle run significantly less than do animals on an ad lib schedule. Adaptation to the wheel, however, was found by Routtenberg (1968) to ameliorate the effect on initial food-intake suppression but not on self-starvation. Routtenberg (1968) postulated that two factors are contributing to the self-starvation phenomenon: "deprivation stress" and "novelty stress." It was hypothesized that the endocrine system may play an important role and, more specifically, that "self-starvation is brought about by an adreno-cortical response driven by the posterior hypothalamus [po 238J." The mechanism would presumably operate through the hypothalamic control over the adenohypophysis via the hypothalamic-hypophyseal portal system and the consequent secretion of ACTH followed by an increased output of glucocorticoids from the adrenal cortex.

Activity and food-restriction effects on gastric glandular lesions in the rat: The activity-stress ulcer

“…Control rats placed on the same feeding schedule but housed in standard laboratory cages without access to an activit y wheel usually ate more than experimental rats and survived the durat ion of the experimental period. This "self-starvation " effect (Routtenberg & Kuznesof, 1967) has been frequently replicated by Routtenberg (I968) and other investigators (Barboriak & Knoblock, 1972;Spatz & Jones, 1971 ;Strutt & Stewart, 1970). …”

The effect of ACTH administration upon activity-related self-starvation

“…This "self-starvation" phenomenon was replicated by Strutt & Stewart (1970). Routtenberg (1968) proposed that two factors are operative in this phenomenon, "deprivation stress" and "novelty stress," 'This research was supported by National Science Foundation Undergraduate Research Program Grant GY-4295.…”

“…20 (5) and hypothesized that the endocrine system, in particular the adrenal cortex, may play an important role in the response of Ss to these stressors. Strutt & Stewart (1970) hypothesized that the proposed adrenocortical response of experimental Ss might involve an increased output of glucocorticoids that would, by means of gluconeogenesis, make glucose available which would perhaps facilitate running and suppress food consumption (Mayer, 1953). The blood glucose levels of experimental Ss did not follow the predictions concerning an ad r en 0 cor tic a I r e s po n s e -drive n phenomenon and were found to be significantly lower in the active Ss.…”

“…Sixteen Wahmann activity wheels, the home room, feeding room, and diet were identical to those reported by Strutt & Stewart (1970). The home-room temperature was maintained at 72° ± 4°F.…”

“…The preexperimental treatment procedure was the same as described by Strutt & Stewart (1970). Six days before the onset of the experimental procedures the Ss were divided into two equal groups, balanced according to body weight and litter affiliation.…”