Effects of bilateral ovariectomy and postoperative hormonal replacement therapy with 17beta-estradiol or raloxifene on serum leptin levels.

OBJECTIVE: To verify the effects of hypoestrogenism and replacement therapy on body mass index (BMI) and leptin in ovariectomized women. DESIGN: We conducted a longitudinal study on 56 women undergoing abdominal bilateral ovariectomy divided into three groups: 19 untreated controls, 18 scheduled to receive 17beta-estradiol, and 19 on raloxifene starting 15 days after surgery. Height, weight, and BMI were recorded on the day of surgery, 5 and 15 days later, and then after 6 months. Leptin and estradiol concentrations were determined by radioimmunoassay on the day of surgery, days 1, 5, and 15, and 6 months after. RESULTS: Leptin levels rose significantly on the day after surgery [median (range): 18.2 (9.8-25.0), 12.5 (9.1-20.9), and 20.5 (12.9-24.5); P< 0.01 v basal] and returned to values similar to baseline on day 5 in all groups. Six months later, controls showed significantly higher leptin levels in comparison with both treated women and basal values [median (range): 19.7 (10.4-22.8), 11.0 (7.6-16.9), and 13.5 (9.1-14.8) ng/ml; P< 0.01). Estradiol levels decreased in all groups, reaching statistical significance 5 days after surgery ( P< 0.01 v basal). A significant rise was observed 6 months after surgery in women treated with estrogens ( P< 0.01). Six months after surgery, BMI increased in untreated controls in comparison with treated women and baseline, although not significantly. CONCLUSIONS: The absence of modifications in leptin on days 5 and 15 after ovariectomy suggests that, in humans, estrogens may not exert an important effect on leptin secretion. After 6 months, replacement therapy maintained leptin levels and BMI was unmodified, whereas untreated controls showed a significant increase in leptin and a trend toward higher BMI, suggesting that replacement therapy may prevent changes in fat distribution and in leptin levels.

Antipituitary antibodies in adults with apparently idiopathic growth hormone deficiency and in adults with autoimmune endocrine diseases.

The role of antipituitary antibodies (APA) in autoimmune pituitary diseases still needs to be clarified. The aim of this study was 2-fold: first, to investigate the presence of APA in adults with idiopathic or acquired GH deficiency (GHD) and in adults with autoimmune endocrine diseases; and second, to evaluate whether in autoimmune endocrine patients APA titer is correlated to the pituitary function and particularly to GH secretion. We studied 12 adults with isolated and apparently idiopathic GHD who were treated with recombinant GH in childhood (group 1a), 14 patients with adult GHD secondary to surgery for pituitary and parasellar tumors (group 1b), and 180 patients with organ-specific autoimmune diseases (group 2). APA were evaluated by indirect immunofluorescence. In all APA-positive patients and in 20 APA-negative patients of group 2, GH secretion was investigated by testing its response to insulin-induced hypoglycemia (insulin tolerance test) and, when impaired, also to arginine. APA were found (at high titers) in 4 of 12 patients of group 1a (33.3%) but were absent in all patients in group 1b. APA were also found in 40 of 180 patients of group 2 (22.2%), 35 of them at low titers (group 2a) and 5 at high titers (group 2b). Twenty of the 140 autoimmune endocrine APA-negative patients studied (group 2c) and all APA-positive patients at low titers (group 2a) had normal pituitary function. Conversely, all APA-positive patients at high titers (groups 1a and 2b) had a severe isolated GHD. An inverse correlation between APA titers and GH peak serum response to insulin tolerance test in autoimmune endocrine patients was observed. Our results suggest that APA, when detected at high titers, may be considered a good diagnostic tool to highlight the possible occurrence of GHD in adults with autoimmune endocrine diseases. Moreover, they may indicate an autoimmune pituitary involvement in adults with apparently idiopathic GHD, suggesting that the prevalence of autoimmune GHD is much higher than that so far considered.

Menstrual status and serum leptin levels in anorectic and in menstruating women with low body mass indexes.

OBJECTIVE: To evaluate serum leptin levels in anorectic women, menstruating women with low body mass indexes (BMI) and normally menstruating women with normal BMI. DESIGN: Prospective study. SETTING: University clinics. PATIENT(S): Fourteen amenorrheic patients with anorexia nervosa (group A), 11 menstruating women with a BMI <18 kg/m(2) (group B), and 20 normal controls. MAIN OUTCOME MEASURE(S): Determination of BMI, caloric intake, total fat mass, ovarian volume, and serum leptin, insulin-like growth factor I, FSH, LH, E(2), PRL, and TSH levels. INTERVENTION(S): None. RESULT(S): Mean BMI and fat mass were similar in groups A and B and significantly higher in controls. Mean caloric intake was significantly lower in group A than in group B and controls. Median serum leptin levels were significantly lower in group A than in group B and controls, and significantly lower in group B than in controls. Median serum insulin-like growth factor I levels were significantly lower in group A than in group B and controls. Binary segmentation analysis of groups A and B showed that LH was the most relevant variable in differentiating the two groups, followed by leptin. CONCLUSION(S): A threshold of leptin levels exist above which, even in the presence of low body mass indexes, the menstrual function is preserved.