The effect of short-term treatment with recombinant human thyroid-stimulating hormones on leydig cell function in men.
ABSTRACT High levels of thyroid-stimulating hormone (TSH) have been implicated as a cause for precocious puberty associated with severe long-standing juvenile hypothyroidism. Recombinant human thyroid-stimulating hormone (rhTSH) is available for the management of patients with thyroid carcinoma, and after its administration the serum TSH levels are similar to those observed in hypothyroid infants with precocious puberty. Our objective was to investigate whether rhTSH increased testosterone secretion in adult males with differentiated thyroid carcinoma. Thirty-one adult Caucasian men, ages 18-59 years, with differentiated thyroid carcinoma were studied. While continuing on thyroid hormone therapy, patients received 0.9 mg of rhTSH 24 hours apart. Blood samples were obtained before the first rhTSH dose (day 1) and at 24 hours (day 3) and 72 hours (day 5) after the second rhTSH dose. TSH, total testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were determined. Serum TSH levels were increased at day 3 (129.2 +/- 5.7 micro U/mL) versus day 1 (0.6 +/- 0.2 micro U/mL) but observed differences in total testosterone, LH and FSH throughout the study were not statistically significant. In conclusion, short-term elevations in serum TSH levels in the range reported in hypothyroid boys with precocious puberty did not increase serum testosterone levels in adult men.
[Show abstract] [Hide abstract]
ABSTRACT: Adipose cells are extrathyroidal targets of thyroid-stimulating hormone (TSH). TSH stimulates interleukin-6 (IL-6) release from adipocytes. We examined TSH responsiveness as a function of stage of differentiation or adipose tissue depot in cultured adipose cells and determined the effect of TSH on extrathyroidal IL-6 production in vivo. Stromal preadipocytes, isolated from human abdominal subcutaneous or omental adipose tissue, and their differentiated counterparts were studied. IL-6 protein concentration in the medium was measured after TSH stimulation. Basal IL-6 release was greater for preadipocytes than differentiated adipocytes, whether derived from subcutaneous or omental fat depots. A depot-dependent effect (omental > subcutaneous) on basal IL-6 release was observed for preadipocytes (1.6-fold, P < 0.05); a similar trend for differentiated adipocytes was not significant (6.2-fold, P > 0.05). IL-6 responsiveness to TSH was observed upon differentiation, but only for subcutaneous adipocytes (1.9-fold over basal, P < 0.001). To determine if TSH could stimulate IL-6 release from extrathyroidal tissues in vivo, we measured serum IL-6 levels from five thyroidectomized patients who received recombinant human (rh) TSH and found that levels increased by threefold on days 3 and 4 (P < 0.05) after its administration. Our data demonstrate that stage of differentiation and fat depot origin affect basal and TSH-stimulated IL-6 release from adipose cells in culture. Furthermore, rhTSH elevates serum IL-6 response in thyroidectomized patients, indicating an extrathyroidal site of TSH action.AJP Endocrinology and Metabolism 07/2006; 290(6):E1140-4. DOI:10.1152/ajpendo.00516.2005 · 4.09 Impact Factor