体重減少の性機能に及ぼす影響 The effects of weight loss on hypothalamo-pituitary-ovarian function タイジュウ ゲンショウ ノ セイキノウ ニ オヨボス エイキョウ
The effects of weight loss on hypothalamo-pituitary-ovarian function
タイジュウ ゲンショウ ノ セイキノウ ニ オヨボス エイキョウ
Recently, in teenagers, amenorrhea associated with weight loss is common in secondary amenorrhea. However, pathophysiology and prognosis of this amenorrhea remain controversial. In this study, the effects of weight loss on hypothalamo-pituitary-ovarian function were investigated in human and rat. 1. Clinical study on amenorrhea associated with weight loss. Thirty five patients with amenorrhea associated with weight loss were entered in this study. 75% of weight loss was caused by self-imposed weight loss for cosmetic reason, however, 60% of patients before weight loss was within the normal range of body weight. On the first visit to our outpatient clinic, 20% of patients was amenorrhea 1st grade and 80% was amenorrhea 2nd grade and the severity of amenorrhea was well correlated with weight loss. Basal LH levels were significantly lower than that ofmid-follicular phase and well correlated with weight loss (r=0.625). A correlation of FSH levels with weight loss could not be found. Pituitary response to GnRH was strikingly impaired in the patients group under 80% of original body weight and hyperresponses were shown in those with 80-90% of orignal body weight and a normal response in those with over 90% of original body weight. 57% of patients (20/35) resumed their normal menstrual cycles finally. Cumulative recovery rate of ovulatory cycle was 5.5% at 2 years， 38.9% at 3 years, 50% at 4 years and 72.2% at 5 years after the onset of amenorrhea. The patients who resumed their normal menstrual cycle had higher recovery rate of body weight than persistent amenorrheic patients (97.3±6.1% of original weight v. s. 84.7%±7.8%). 81.8% of patients with good recovery rate (over 90% orignal body weight) resumed their normal menstrual cycle. On the other hand, only 15.3% of patients with poor recovery rate (under 90%) resumed menstruation. 2. The effects of weight loss on the gonadal function and brain catecholamineneuron's function in rats. Continuous diestrus cycles occurred at 86.6 % of original body weight in subacute starved female Wistar rats (SS) (N=11). Estrus cycles were resumed in 89% (8/9) of rats with 92% of orignal body weight. Serum LH， FSH and estradiol levels were lower than in control or chronic starvation (CS) group LH, but not FSH nor estradiol in CS was lower than control. Dopamine (DA), dihydroxyphenyl-acetic acid (DOPAC) and homovanililc acid (HVA) contents except norepinephrlne (NE) of preoptic suprachiasmic area in SS were lower than control and CS. There were no differences in NE, DA, DOPAC, HVA and serotonin content of mediobasal hypothalamusamong them. Cyclic reproductive mechanism can recover in spite of extremely low catecholamine levels, because of brain compensation with increased postsynaptic sensltivity. These results suggest that not only weight loss, but also rapidity of weight loss greatly affect the hypothalamo-pituitary-ovarian function. Amenorrhea associated with weight loss is reversible, however, a long time is necessary for the restoration of menstruation after weight recovery. Dopaminergic activity in the hypothamus is impaired by starvation, but the role of suppressed catecholamine on the impaired gonadal function after weight loss is permissive.
医歯学総合研究科博士論文(医学) ; 学位取得日: 平成2年11月1日