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Purpose: To evaluate the impact of high thyroid stimulating hormone (TSH) levels on human granulosa–luteal (hGL) cells. Methods: hGL cells were isolated from follicular aspirates derived from patients undergoing IVF treatment without any thyroid disorder (serum TSH 0.5–2 mU/L). Cells were cultured at 37 °C in DMEM, supplemented with 5% FBS. The cells were treated with 1 nM LH and increasing concentrations of TSH. At the end of culture, conditioned medium and cells were collected to analyze progesterone production, cell viability, and mRNA levels of genes involved in the steroidogenesis process. Human ovarian tissues were analyzed for TSH receptor (TSHR) expression by IHC. Results: The expression of TSHR was detected in human corpus luteum by IHC and in hGL by RT-PCR. In hGL cells, TSH treatment did not modulate progesterone production nor the expression of steroidogenic genes, such as p450scc and HSD3b 1/2. However, TSH induced a dose-dependent increase in cell death. Finally, TSH did not affect LH-induced p450sccand HSD3b1/2expression while LH partially reverted TSH negative effect on cell death in hGL. Conclusions: Elevated TSH levels in hypothyroid women may be associated with impaired CL functioning and maintenance. These findings open a new line of research for the importance of the treatment of women with thyroid dysfunction that could contribute to the onset of infertility.

Testosterone by promoting different metabolic pathways contributes to short-term homeostasis of skeletal muscle, the largest insulin-sensitive tissue and the primary site for insulin-stimulated glucose utilization. Despite evidences indicate a close relationship between testosterone and glucose metabolism, the molecular mechanisms responsible for a possible testosterone-mediated insulin-like effects on skeletal muscle are still unknown. Here we used undifferentiated proliferating or differentiated human fetal skeletal muscle cells (Hfsmc) to investigate the short-term effects of testosterone on the insulin-mediated biomolecular metabolic machinery. GLUT4 cell expression, localization and the phosphorylation/activation of AKT, ERK, mTOR and GSK3β insulin-related pathways at different time points after treatment with testosterone were analyzed. Independently from cells differentiation status, testosterone, with an insulin-like effect, induced Glut4-mRNA expression, GLUT4 protein translocation to the cytoplasmic membrane, while no effect was observed on GLUT4 protein expression levels. Furthermore, testosterone treatment modulated the insulin-dependent signal transduction pathways inducing a rapid and persistent activation of AKT, ERK and mTOR, and a transient inhibition of GSK3β. T-related effects were shown to be androgen receptor dependent. All together our data indicate that testosterone through the activation of non-genomic pathways, participates in skeletal muscle glucose metabolism by inducing insulin-related effects.

Through the use of somatic cell hybrids segregating either human or rat chromosomes, we determined the chromosome localizations of two genes encoding cAMP-specific phosphodiesterases (cAMP-PDEs). PDE4D, the gene encoding the cAMP-PDE isoform 3 (IVd), was assigned to human chromosome 5 and rat chromosome 2, and PDE4B, the gene encoding the cAMP-PDE isoform 4 (IVb), was assigned to human chromosome 1 and rat chromosome 5. These localizations extend the homology between rat chromosome 2 and human chromosome 5, on the one hand, and between rat chromosome 5 and human chromosome 1 on the other hand.