S Reiser

Seasonal variation in plasma glucose and hormone levels in adult men and women.

Twenty-nine men and women collected diet records for 1 yr. Fasting blood samples were collected four times during the year so that each season of the year was represented. An oral glucose tolerance test was given in the spring and in the fall. Regardless of season men consumed significantly more kilocalories, carbohydrate, sugar, and starch than did the women. Men consumed more simple sugars in the fall than in the spring. No seasonal effect was observed for calories, total carbohydrate, or starch intake. Fasting glucose and insulin were higher in the fall than in the spring. Summed insulin levels after the oral glucose tolerance were significantly different by age and season. Summed insulin levels were significantly higher in older than younger subjects; men and older subjects had higher levels in the spring than in the fall. Fasting levels of thyroxine, free thyroxine, triiodothyronine, and glucagon varied significantly with the season. A significant sex by season interaction was observed in the thyroid hormones. It appears that seasonal variation as well as diurnal variation should be considered in evaluating hormone levels.

Sexual Differences in the Expression of Copper Deficiency in Rats

Abstract The present investigation was undertaken to establish whether the severity of copper deficiency in rats fed diets containing fructose is affected by the presence and type of endogenous sex hormones. Intact and castrated male rats and intact and ovariectomized females were fed from weaning a copper-deficient diet (0.6 ppm) containing 62% fructose for 8 weeks. Regardless of castration, male rats were anemic, exhibited heart hypertrophy, and died of the deficiency. However, castration ameliorated the anemia and delayed the mortality. In contrast, none of the females died of the deficiency. It is suggested that in addition to the sex of the animal, levels of testosterone in the male may also play a role in the severity of copper deficiency.

Effect of dietary carbohydrates and copper status on blood pressure of rats

Copper deficiency was induced in rats by feeding diets containing either 62% starch, fructose or glucose deficient in copper for 6 weeks. All copper deficient rats, regardless of the dietary carbohydrate, exhibited decreased ceruloplasmin activity and decreased serum copper concentrations. Rats fed the fructose diet exhibited a more severe copper deficiency as compared to rats fed either starch or glucose. The increased severity of the deficiency was characterized by reduced body weight, serum copper concentration and hematocrit. In all rats fed the copper adequate diets, blood pressure was unaffected by the type of dietary carbohydrate. Significantly reduced systolic blood pressure was evident only in rats fed the fructose diet deficient in copper. When comparing the three carbohydrate diets, the physiological and biochemical lesions induced by copper deprivation could be magnified by feeding fructose.

Sexual Differences in Copper Deficiency

Since female rats have been shown to be protected against the mortality of copper deficiency of male rats when fructose is fed, we designed a study to establish whether castration of the male rat will protect but ovariectomy of the female will exacerbate the signs of copper deficiency.

Relationships of glucoregulatory hormones in normal and hyperinsulinemic men consuming fructose

Abstract Twelve hyperinsulinemic men and twelve controls matched for age, weight, and height were fed a normal American diet containing 0, 7.5, and 15% added fructose for 5 weeks each in a crossover design. Fasting insulin and T 4 increased as fructose intake increased in both groups. T 4 levels were higher in controls than in hyperinsulinemic men. There were no significant differences in fasting plasma cortisol, growth hormone, or testosterone levels. In the hyperinsulinemic men there were positive correlations between cortisol and T 4 , cortisol and testosterone, and testosterone and T 4 . The correlation between T 4 and insulin was negative. In the normal men the correlation between insulin and T 4 was positive as were the correlations between cortisol and testosterone and cortisol and growth hormone. These results indicate that there may be different hormonal relationships in hyperinsulinemic and normal men.