Karl M. Pirke

Behavioral and biological correlates of dietary restraint in normal life

Based on laboratory results, restrained eating has been linked to the development of binge eating and eating disorder syndromes such as bulimia nervosa. This study was designed to extend the scope of investigation of the concept of restrained eating beyond the laboratory. Eating behavior and biochemical indices of nutritional state were investigated in 60 young women, who were divided in restrained and unrestrained eaters by questionnaire. Seven-day records of food intake showed that the high-restraint group ate around 400 kcal a day fewer than the low-restraint group. Group differences in actual macronutrient intake and long-term food preferences pointed to a qualitatively altered eating pattern in restrained eaters. Actual protein portion was higher in restrained eaters. They tried to avoid calorie dense food items of high carbohydrate and fat content. Instead, they preferred food regarded as low-caloric and healthy. Plasma levels of triiodothyronine and glucose, which could be taken as indices of long-term adaptation to starvation, were not decreased in the high-restraint group. However, significantly higher levels of triglycerides in restrained eaters may reflect a biological state due to short-term starvation. The results indicate that the concept of dietary restraint predicts eating behavior not only under experimental conditions, but also in normal life. As a consequence of altered eating patterns, psychological and physiological deprivation can be hypothesized in restrained eaters, making them prone to the occurrence of overeating.

Relationship between weight gain and hypothalamic pituitary adrenal function in patients with anorexia nervosa

Abstract Sixteen patients with anorexia nervosa, aged 13 to 29, were studied after adaption to the hospital for one week when they had 63% (51–77%) of their ideal body weight (IBW). A 24-h secretory profile of plasma Cortisol repeated after initial weight gain of 10% in IBW and on discharge and a dexamethasone suppression test with blood sampling from 9.00 h to 19.00 h repeated at each 10% increase in IBW were ascertained. With one exception all patients had either an insufficient suppression or showed an early escape from suppression after dexamethasone administration. After an increase of only 10% in IBW normal suppressibility of the hypothalamic pituitary unit was seen in all patients except for three who showed a more delayed recovery. The 24-h profile of plasma cortisol was characterized by an increased number of secretory episodes, an increase in the time spent in secretory activity, an elevated 24-h mean level and a prolonged plasma half-life. Highly significant changes were seen after initial weight gain and only slight, non-significant changes after final weight gain. It is concluded that starvation-induced metabolic changes in patients with anorexia nervosa lead to a delayed degradation of cortisol and to a central endocrine dysfunction characterized by an increased secretory activity and an insufficient glucocorticoid feedback. Recovery from all endocrine dysfunctions reported here is rapidly achieved during weight gain of only 10% in IBW.

Effects of testosterone replacement on sexual behavior in hypogonadal men

Fifteen patients with hypogonadism due to testicular, pituitary, or hypothalamic failure were studied. After a pretreatment period without substitution, patients received intramuscular injections of testosterone enanthate, equivalent to 25, 50, 100, and 250 mg testosterone, or placebo. Each dose was given for 4 weeks, with injections given every 2 weeks. All patients with plasma testosterone values below 2 ng/ml during the pretreatment period reported impaired sexual function. They responded to testosterone injections (50, 100, and 250 mg) with improvement of sexual behavior, as rated by sexual desire and frequency of erections and ejaculations. In the range between 2.0 and 4.5 ng testosterone per ml, four patients reported high frequencies of erections and ejaculations that did not change after testosterone treatment. Four other patients with testosterone values in the same range reported impaired sexual behavior and were successfully treated with testosterone enanthate. These data indicate that male sexual behavior is testosterone dependent and that the individual limit of plasma testosterone below which sexual behavior is impaired lies between 2.0 and 4.5 ng/ml.

Nocturnal Increase of Plasma Testosterone in Men: Relation to Gonadotropins and Prolactin

The nocturnal increase of plasma testosterone (T) in adult men has been well established. Luteinizing hormone (LH) does not show a similar increase throughout the night, whereas prolactin (PRL) does, suggesting the possibility of other hormone influence on T secretion. To investigate this possibility, 8 young adult men were studied for 4 consecutive nights in the sleep laboratory (2 nights adaptation, 2 nights blood sampling), by blood samples taken every 30 min during the 8-h sleep period, for measurement of LH, follicle stimulating hormone (FSH), PRL, and T. LH and FSH were secreted episodically, with little or no change in baseline levels during the night. PRL and T also were secreted episodically, but their baseline levels increased as the night progressed. Both LH and PRL had maximum within-subject correlations (averages equal +0.35 and +0.48 respectively) with T when they led T by 60 min. Within-subject correlations done on first differences (to remove the effect of slow trends) were near zero. LH and PRL had larger correlations with T than did FSH, for both calculations. These data suggest that both LH and PRL levels precede T levels by about 60 min. PRL thus may participate in the regulation of nocturnal T secretion in adult men.

Dieting influences the menstrual cycle: vegetarian versus nonvegetarian diet

Eighteen healthy, normal-weight women aged 19 to 27 years who had regular ovulatory menstrual cycles volunteered for the study. Blood was drawn on Mondays, Wednesdays, and Fridays throughout the control cycle and during a 6-week diet period that began with commencement of a new cycle. Nine women followed a vegetarian diet and nine a nonvegetarian diet. Both groups lost an average of 1 kg body weight/week. Seven of nine women in the vegetarian group became anovulatory. During the vegetarian diet the average luteinizing hormone (LH) values were significantly decreased during the midcycle and the luteal phase. Estradiol (E2) and progesterone (P) values were significantly lower during the luteal phase. In contrast, the nonvegetarian group did not show significant reduction of LH, E2, and P values during any part of the menstrual cycle. Seven of nine women in the nonvegetarian diet group maintained ovulatory cycles with no changes in cycle length or in the length of the follicular phase. In one woman who became anovulatory, E2 values did not increase during the follicular phase.

Psychosexual stimulation and plasma testosterone in man

Plasma testosterone was measured every 15 min for 3 1/2 hr in eight male subjects before, during, and after the showing of a sexually explicit movie. There was an average increase of 35% in testosterone. The maximum concentration was observed 60–90 min after the end of the film. No increase was found in eight control subjects who saw a sexually neutral film.

Circadian rhythms in endogenous depression

A comprehensive study of circadian rhythms was carried out in 16 drug-free patients with endogenous depression, 10 of whom were reinvestigated after clinical remission, and 10 healthy controls. No free-running periods were observed in body temperature, urinary excretion of potassium and free cortisol, or any other variable. Moreover, there was little, if any, indication of phase-advance. The circadian variation of several variables was reduced during depression, e.g., motor activity, body temperature, and (less markedly) urinary potassium, but not cortisol. The circadian worsening of mood tended to occur around the time of awakening during depression, i.e., several hours later than after remission or in normal controls. In patients with circadian variation of self-rated mood, the acrophase of this variable correlated significantly with that of urinary free cortisol. This indicates an entrainment of the disease process to the circadian rhythm of cortisol secretion, probably via circadian variations of neurotransmitters in the hypothalamus. The other circadian phenomena observed in depression can adequately be explained by masking effects (negative or positive) of psychopathological symptoms (e.g., early morning awakening) on overt circadian rhythms.

Dieting causes menstrual irregularities in normal weight young women through impairment of episodic luteinizing hormone secretion

Thirteen healthy, normal weight young women were studied throughout a control cycle and a diet cycle, during which they lost 1kg per week on a vegetarian 800kcal diet. Blood was sampled daily in the morning, and at weekly intervals, collected at 10-minute intervals for 6 hours. Follicle growth was monitored by ultrasonic measurement. All subjects showed normal cyclic gonadal function during the control cycle. Cyclic gonadal function remained unaltered in two subjects during the diet cycle. No dominant follicle developed in seven others, while another four showed apparently normal follicular development but impaired progesterone secretion by the corpus luteum. Comparison of both cycles revealed that episodic luteinizing hormone (LH) secretion during the follicular phase was altered by dieting. Average LH concentrations and the frequency of episodic secretions were significantly reduced during the follicular phase but not during the luteal phase. Follicle-stimulating hormone was unaltered.

Psychobiology of anorexia nervosa.

The psychobiology of anorexia nervosa is described and explained under four headings; (1) the psychopathology as related to the motivation for fasting; (2) metabolic and somatic consequences of starvation, including brain morphology; (3) endocrine abnormalities in the hypothalamic-pituitary-adrenal and gonadal axis; and (4) the hunger drive and its possible perversions in terms of aspects of neuroethology and the reward system in the brain.

The Psychobiology of Anorexia Nervosa

The psychobiology of anorexia nervosa is described and explained under four headings; (1) the psychopathology as related to the motivation for fasting; (2) metabolic and somatic consequences of starvation, including brain morphology; (3) endocrine abnormalities in the hypothalamic-pituitary-adrenal and gonadal axis; and (4) the hunger drive and its possible perversions in terms of aspects of neuroethology and the reward system in the brain.