Thyrotropin versus thyroid hormone in regulating bone density and turnover in premenopausal women.

OBJECTIVE: This cross-sectional study aimed to evaluate the interrelations between endogenous TSH level on one side and the status of bone mineral density (BMD) and bone metabolic turnover (BMT) on the other in pooled four groups of premenopausal women either without or with a long-term L-thyroxine treatment. METHODS: Serum levels of free thyroxine (FT4), thyrotropin (TSH), calcium (Ca), alkaline phosphatase (ALP), osteocalcin OC) and cross linked N-telopeptide of type 1 collagen (NTx) as well as urinary calcium (U-Ca/24h), bone mineral density of lumbar spine L 1-4 (BMD-L) and femoral hip (BMD-F) were estimated in a cohort of 151 premenopausal women (median 36 years) consisting of four groups: Group 1, 40 healthy untreated women, while three other groups consisted of patients previously treated for about 5 years; Group 2, 41 patients with genuine hypothyroidism treated by L-thyroxine (50-100 microg daily); Group 3, 40 patients with genuine hyperthyroidism treated by Carbimazol (10-15 mg daily); Group 4, 30 patients treated by suppressive doses of L-thyroxine (100-150 microg daily) after thyroidectomy for thyroid cancer (n=10) or because of progressively growing benign goitre (n=20). RESULTS: When using multiple correlation analysis (Pearson's r) in pooled 151 women, TSH showed significant positive correlation with BMD-L (p<0.01) and BMD-F (p<0.001) and, at the same time, significant negative correlation with serum level of BMT markers such as ALP (p<0.05), OC (p<0.05) and NTx (p<0.01), while the correlation of FT4 with BMD-L, BMD-F was significantly negative (p<0.001 for both) and that with all BMT markers was significantly positive (p<0.05 to <0.001). Thus, it appeared that higher TSH level was associated with increased bone mineral density and, at the same, with decreased bone metabolic turnover. These interrelations were further supported by the findings of significantly lower BMD-F (p<0.01), BMD-L (p<0.001) and significantly higher ALP, OC and NTX (all at p<0.001) in the group of 36 women with TSH level<0.3 mU/l as compared to the group of 115 women with TSH level range of 0.35-6.3 mU/l). CONCLUSIONS: Irrespectively of thyroid diagnosis and/or previous long term thyroxine treatment in some groups, this cross sectional study showed that, after the pooled group of 151 women has been redistributed according to the actual TSH level, the bone mineral density and the level of bone turnover markers was significantly more favorable in 115 subjects with TSH level range of 0.35-6.3 mU/l than these in 36 women with TSH<0.3 mU/l.

Effect of growth hormone replacement therapy on plasma brain natriuretic peptide concentration, cardiac morphology and function in adults with growth hormone deficiency.

OBJECTIVE: The impact of growth hormone (GH) replacement on plasma brain natriuretic peptide (BNP) in association with cardiac morphology and function in adults with growth hormone deficiency (GHD) was evaluated. SUBJECTS AND METHODS: Fifty nine adult patients with GHD (29 men, age 19-59 years) received a starting dose of 0.1-0.2 mg/day recombinant GH, which was subsequently adjusted to the 50th percentile of normal serum insulin-like growth factor (IGF-1) over a 6 month period. Plasma BNP and IGF-I levels before, 3 and 6 months after treatment were determined, as were the echocardiographic data, such as ejection fraction (EF), left ventricular end-diastolic volume (LVEDV), left ventricular end-diastolic diameter (LVEDD), interventricular septal thickness (IVST), posterior wall thickness (PWT), left ventricular mass (LVM), E/A wave and deceleration time (DT). RESULTS: Mean plasma BNP levels (53.1+/-8 pg/ml) and echocardiographic parameters were within the normal range at baseline, although men had higher LVM, IVST, PWT, LVEDV and LVEDD, respectively. A significant decrease in plasma BNP was observed after 6 months (27+/-5.6 pg/ml, P<0.05). No significant changes in echocardiographic parameters were observed except for a mild tendency to increase in LVM, and a borderline decrease in DT (181+/-8.1 vs. 155+/-9 ms, P<0.01). CONCLUSIONS: Six months GH replacement therapy induced a significant decrease in plasma BNP levels despite the majority of patients having plasma BNP within the normal range at baseline. A borderline decrease in diastolic deceleration time was observed, the clinical significance of which is unclear.