Construction and expression of vectors encoding biologically active rodent gonadotropins.

The gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), are important hormones in vertebrate reproduction. The isolation of gonadotropins from the pituitary gland is sub-optimal, as the cross-contamination of one hormone with another is common and often results in the variation in the measured activity of LH and FSH. The production of recombinant hormones is, therefore, a viable approach to solve this problem. This study aimed to express recombinant rat, mouse, and mastomys FSH and LH in Chinese hamster ovary (CHO) cells. Their common α-subunits along with their hormone-specific ß-subunits were encoded in a single mammalian expression vector. FSH from all three species was expressed, whereas expression was achieved only for the mouse LH. Immunohistochemistry for rat alpha subunit of glycoprotein hormone (αGSU) and LHß and FSHß subunits confirmed the production of the dimeric hormone in CHO cells. The recombinant rodent gonadotropins were confirmed to be biologically active; estradiol production was increased by recombinant FSH in granulosa cells, while recombinant LH increased testosterone production in Leydig cells.

Tumorigenesis inheritance from the putative progenitor species of Nicotiana rustica.

Hybrid seedlings from crosses of Nicotiana rustica×N. langsdorffii and N. rustica×N. alata show tumors including teratomas and vitrification. In the present study, we attempted to elucidate the genetic background leading to tumorigenesis and vitrification from the viewpoint of the amphidiploidy of N. rustica. The species N. undulata, N. paniculata, and N. knightiana have been suggested to be the progenitors of N. rustica or closely related to its progenitors. We tested tumorigenesis in interspecific hybrids between these putative progenitors of N. rustica and N. langsdorffii or N. alata, which are the species in section Alatae. The hybrid seedlings were cultured in test tubes and their morphological characteristics were observed. According to previous reports, most of the hybrid seedlings from the crosses N. rustica×N. langsdorffii and N. rustica×N. alata formed tumors and showed vitrification. In crosses with every putative progenitor of N. rustica, a portion of hybrid seedlings formed tumors and showed vitrification. These observations suggested that N. rustica inherited the factors leading to expression of abnormal symptoms from its putative progenitors. We also observed the influence of high temperature on the expression of abnormal symptoms of hybrid seedlings from the cross N. rustica×N. alata. While these hybrids developed teratomas and other tumors at 28°C, when cultured at 34°C, they did not show any abnormalities. This is the first report to show that phenotypic abnormalities in hybrid seedlings of N. rustica×N. alata are temperature sensitive.

Sex differences in spatiotemporal expression of AR, ERα, and ERß mRNA in the perinatal mouse brain.

It has been shown that every masculinized function might be organized by a particular contribution of androgens vs. estrogens in a critical time window. Here, we aimed to investigate the sex differences in brain testosterone levels and in the spatiotemporal dynamics of steroid receptor mRNA expression in perinatal mice, by using enzyme immunoassay and real-time PCR, respectively. We found that testosterone levels in the forebrain transiently increased around birth in male mice. During the perinatal period, levels of androgen receptor mRNA in the hypothalamus (hypo) and prefrontal cortex (PFC) were higher in male mice than in female mice. Estrogen receptor α (ERα) mRNA levels in the hypo and hippocampus were higher in male mice than in female mice before birth. In contrast, ERß mRNA expression in the PFC was higher in female mice immediately after birth. These spatiotemporal sex differences in steroid receptor expression might contribute to organizing sex differences of not only reproductive function, but also anxiety, stress responses, and cognition in mice.