Hypothalamic control of energy balance and the reproductive cycle in the rat

Response : Menarche and Fatness: Reexamination of the Critical Body Composition Hypothesis

“…It is known that too much fat, in addition to too little fat, is associated with the cessation of reproductive ability in the human female (and male), as well as in other animals (17,18,25). Our experimental findings at the first estrus of the rat (26) based on actual carcass components (27), also support the importance of a fat/lean ratio and Kennedy's hypothesis (16,19).…”

“…The findings of G. C. Kennedy on body weight, food intake, and puberty, and fat depots, in the rat were particularly important (16)(17)(18)(19) …”

The constancy of the energy expended by rats on spontaneous activity, and the distribution of activity between feeding and non‐feeding

“…increase in a non-feeding activity with restriction of food intake (Ahrens & Wilson, 1966); decrease in a non-feeding activity (Slonaker, 1925 a) with increased food intake and increased total metabolic rate (Morrison, 1956) in pregnancy; a similar but more pronounced effect in lactation (Brody, Riggs, Kauffman & Herring, 1938); the inverse relationship between food intake and non-feeding activity in phases of the oestrous cycle (Brobeck, Wheatland & Strominger, 1947); the decrease of a non-feeding activity in hypothalamic hyperphagia with its partial restoration to normal in the obese phase when food intake returns towards normal levels (Kennedy & Mitra, 1963).…”

“…Most studies on activity show increase in activity of 50-600 % (Finger, 1951;Kennedy & Mitra, 1963;Richter & Rice, 1954;Slonaker, 1925b) on deprivation of food, while studies on total and 'basal' energy expenditure show no change or a fall in metabolic rate (e.g. Benedict & MacLeod, 1928; Cumming & Morrison, 1960).…”

Morphological studies on adipocytes from obese rats - scanning and freeze-fracturing electron microscopy.

“…The application of the freeze-fracturing technique to adipocytes makes it possible to study the mechanism of fat storage in the cells (12) Male Wistar strain rats of 27 weeks old and young adult rats of 7 weeks old were used as controls. For studies on adipocytes in obesity, hypothalamic obesity was induced b y bilateral electrolytic lesions of the ventromedial hypothalamus of young adult rats (16) . Rats with ventromedial hypothalamic lesions were kindly supplied b y Dr. Chikamori (2nd Department of Internal Medicine of this University) .…”