A study of protein and glycoprotein syntheses in pre-implantation mouse embryos using mini-2D-electrophoresis, video densitometer scanning and computer-image analysis.

In the present study, proteins and glycoproteins of mouse embryos at 2-cell, morula and blastocyst stages were analyzed. The techniques of 35S-Met incorporation, ConA antiserum-precipitating ConA-binding proteins, mini-2D-electrophoresis, fluorography, video densitometer scanning and the computer-image system were used for analyses. Results of the investigations indicated that proteins and glycoproteins were synthesized by the embryos in a gradual increase manner from 2-cell to blastocyst. A relatively large amount of glycoproteins was synthesized during the morula and blastocyst stages. Two specific small glycoproteins respectively with molecular weights about 6500 and 9000 and PIs at 5.0 and 6.5 were apparently synthesized in the blastocyst but not in the 2-cell or the morula.

Effects of chicken and mammalian gonadotropin-releasing hormones (GnRH) on in vivo pituitary gonadotropin release in amphibians and reptiles.

The ability of mammalian and chicken gonadotropin-releasing hormones (GnRH) and their agonistic analogs to stimulate in vivo gonadotropin release were tested in a frog (Rana catesbeiana), snake (Naja naja), and turtle (Sternotherus odoratus). In the frog, chicken and mammalian GnRH were equipotent in stimulating the release of FSH and LH. Attendant increases in plasma androgen and the occurrence of spermiation confirmed the release of biologically active gonadotropin. Neither of the GnRH preparations or their agonists produced significant changes in plasma hormones in either of the reptiles. In light of comparable data for the actions of these GnRH preparations in mammals and birds, it appears that species specificity in the response to different GnRHs does not correlate well with the nature of the homologous hypothalamic GnRH molecule.

Anatomy and function of the reproductive tract in the captive male tree shrew (Tupaia belangeri).

The reproductive anatomy of the male tree shrew (Tupaia belangeri) was examined and compared with other Tupaiidae. The testes are located prepenially in a pigmented scrotum which is fused to the base of a pendulous penis. The terminal portion of the vas deferens is differentiated into an ampullary gland and joins the duct of the seminal vesicle to form a short ejaculatory duct. The prostate is a compact bilateral body drained by a main collecting duct. In the aggregate, these features indicate that the reproductive system in Tupaia is primate in character. Testicular function in tree shrews is affected by both social and seasonal factors. When males were housed communally, the majority exhibited testicular degeneration accompanied by a loss in the weight and fructose content of the seminal vesicles and in pigmentation of the scrotum. These changes may be due to the presence of dominant conspecifics since animals kept in isolation undergo normal sexual development. Animals captured throughout the year and isolated show seasonal fluctuations in androgenic and spermatogenic function. Reproductive capacity is maximal during the winter and minimal during the summer. Local environmental factors appear to regulate reproductive function so that the greatest number of births occur during the dry season.

Adenohypophysial cell-types in the pituitary gland of the soft-shelled turtle, Trionyx sinensis. I. Seasonal cycles.

By using various staining techniques, two acidophilic and three basophilic cell-types have been distinguished in the pars distalis of Trionyx sinensis. Seasonal fluctuations in their cytoplasmic granulation, cell and nuclear size have been compared with seasonal patterns of activity in the gonads, adrenals and thyroid. On the basis of the results, specific functions have been ascribed to each cell-type. Basophils 1 activity closely parallels the seasonal thyroid cycle. Basophils 2 are probably FSH-secreting gonadotropes and their activity correlates with the seasonal cycle of spermatogenesis in the seminiferous tubules. The functional activity of the testicular interstitial cells correlates with the secretory pattern of the basophils 3. That these are LH-secreting cells is also suggested by the epididymidal cycle, which indicates a high level of androgen secretion coincident with the rapid degranulation of these cells, at a time of no spermatogenetic activity. Adrenal activity shows no relationship with the basophils 3 cycle, and chromophobic cells may be the locus of ACTH secretion. Acidophils 2 remain stable throughout the year and are probably somatotropes, but acidophils 1 increase their activity in autumn and are likely to be lactotropes.

PIP: 2 acidophilic and 3 basophilic cell types were identified in the pars distalis of the soft-shelled turtle (Trionyx sinensis) and their function was interpreted. Comparison of seasonal fluctuations in cytoplasmic granulation and cell and nuclear size with seasonal patterns of gonadal, adrenal, and thyroid activities indicated specific functions for each of the cell types. The activity of basophils 1 closely paralleled the seasonal pattern of the thyroid cycle, while basophils 2 are most likely follicle-stimulating-hormone-secreting gonadotropes whose activity correlated with the seasonal pattern of spermatogenesis in the seminiferous tubules. The secretory pattern of the basophils 3 was correlated with the functional activity of the testicular interstitial cells, which suggests that these are luteinizing-hormone-secreting cells. This is supported by a high degree of androgen secretion during the epididymal cycle which coincided with rapid degranulation of these cells at a time when spermatogenesis was in arrest. No apparent correlation between adrenal activity and the basophils 3 cycle was observed. It is suggested that the chromophobic cells may be the site of ACTH secretion. Acidophils 1 increased their activity in the autumn and are probably lactotropic in function, while acidophils 2 activity was stable throughout the year, which suggests that they are likely to be somatotropes.