Differences between men and women as regards the effects of protein-energymalnutrition on the hypothalamic-pituitary-gonadal axis

Although protein-energy malnutrition (PEM) affects 50% of hospitalized pati ents, its effects on the hypothalamic-pituitary-gonadal (HEPG) axis have no t been extensively investigated. To investigate the effects of PEM on the H PG axis in hospitalized patients, 62 inpatients ages 18-91 y (35 men and 27 women) had a nutritional and hormonal evaluation. Hormones were determined in blood samples obtained between 0700 and 1200 h. Patients were divided i nto two subgroups: those with body mass index (BMI) < 18.5 kg/m(2) (low bod y mass index [LBMI]; 16 men, 13 women) and those with BMI > 20 kg/m(2) (nor mal-high body mass index [NHBMI]; 19 men, 14 women). The nutritional parame ters of LBMI patients were inferior to those of NHBMI patients. Total and f ree testosterone levels were subnormal, 31.4% and 17.2% respectively, in al l men; free testosterone was subnormal in 31.25% of LBMI versus 5.3% of NHB MI male patients and total testosterone concentration was subnormal in 43.8 % of LBMI versus 21.1% of NHBMI male patients. Luteinizing hormone (LH) lev el was higher in LBMI men than in NHBMI men, whereas the reverse was the ca se for women, for whom follicle-stimulating hormone (FSH) also was lower in the LBMI group than the NHBMI group. The HPG axis hormones which best disc riminated between the LBMI and NHBMI groups were free testosterone for men and LH and FSH for women, which were all lower in the LBMI than in the NHBM I group. LH was correlated with BMI and midupper arm muscle circumference ( AMC) (women positively and men negatively) but not with triceps skin-fold t hickness (TSF). Total testosterone level was positively correlated with AMC and free testosterone with TSF. Hypogonadism is common among hospitalized patients with PEM. Men with PEM have low testosterone levels with normal or high gonadotropin levels, which suggests impairment of Leydig cell functio n. Women with PEM suffer hypogonadotropic hypogonadism. AMC correlates posi tively with total serum testosterone concentration in men and with LH level s in women, suggesting that satisfactory function of the HPG axis requires a functional (protein) reserve as well as an energy (fat) reserve. (C) Else vier Science Inc. 1999.