Desialylated and deglycosylated human chorionic gonadotropin are superagonists of native human chorionic gonadotropin in human thyroid follicles.

Highly purified human chorionic gonadotropin (hCG) interacts with the thyrotropin (TSH) receptor and stimulates triiodothyronine (T3) secretion, iodide uptake and organification, and cyclic adenosine monophosphate (cAMP) formation in human thyroid follicles. Because of interest in the role of the carbohydrate component in the structure-function relationships of hCG we undertook to deplete hCG of its sialic acid or carbohydrate residues and assess the thyrotropic activity of the carbohydrate-modified forms. For this purpose, we used our assay system consisting of human thyroid follicles cultured and suspended in collagen gel in serum-free medium.

A potential novel mechanism for precocious puberty in juvenile hypothyroidism.

Some children with juvenile hypothyroidism exhibit unexplained precocious puberty. Interaction of TSH with the human FSH receptor (hFSH-R) is a possible pathophysiological mechanism for this syndrome that has not been explored due to the lack of hFSH-free TSH preparations and the scarcity of a suitable hFSH-R-based assay system. To devise an in vitro FSH bioassay suitable for exploring this mechanism, we expressed hFSH-R complementary DNA in COS-7 cells and stimulated them with recombinant hTSH (rec-hTSH).

Increased biological activity due to basic isoforms in recombinant human follicle-stimulating hormone produced in a human cell line.

FSH has four asparagine-linked oligosaccharides with variable sialic acid contents, so that FSH is not a single molecule, but a heterogeneous group of isoforms. These isoforms differ in their biological properties and their distribution changes in various physiological states, allowing the modulation of FSH activity. Recombinant human (h) FSH has been produced in Chinese hamster ovary cells and has an isoform profile similar to those of both pituitary FSH standard and purified urinary FSH.

Human chorionic gonadotropin stimulates thyroid hormone secretion, iodide uptake, organification, and adenosine 3',5'-monophosphate formation in cultured human thyrocytes.

Despite extensive studies, the issue of whether hCG possesses intrinsic thyrotropic activity remains unresolved. This is mainly because in the experimental systems used so far, the parameters measured did not include the thyroid-specific functions of iodine organification and the hormonal end-point response, T3 secretion, and cells of nonhuman origin were employed, constituting a major drawback in view of the wide variation in sensitivity of thyroid responsiveness to hCG in different species. We investigated the thyrotropic activity of hCG, using for this purpose a novel homologous assay system consisting of human thyroid follicles cultured suspended in collagen gel in serum-free medium.

Modulation of the expression of murine lupus by gonadotropin-releasing hormone analogs.

Recent studies have suggested that hypothalamic and pituitary hormones may directly influence the immune system. One such hormone with immunomodulatory properties is GnRH. We hypothesized that GnRH and/or the gonadotropins might alter the severity of autoimmune disease through mechanisms distinct from their effects on gonadal hormones.