Testicular development and serum sex steroid profiles during the annual sexual cycle of the male sturgeon hybrid the bester

Testicular development in the adult male F₁ sturgeon hybrid, the bester ( Huso huso L. female x Acipenser ruthenus L. male), was examined monthly in relation to serum sex steroid levels. Spermatogenesis lasted for 1 year, with meiosis generally starting in September and spermiogenesis in November, although there was considerable variation in testicular developmental stages between fish sampled monthly. Testicular development continued, slowly, during the winter months until April. Fish did not exhibit spontaneous spermiation, and phagocytotic activity of Sertoli cells became prominent from May onwards. Androgen levels increased during Spermatogenesis and remained high throughout the pre-spermiation period. In the degeneration stage, 11-ketotestosterone concentrations declined to low levels, while testoster- one levels remained high. The serum concentration of 17,20β-dihydroxy-4-pregnen-3-one was low throughout the reproductive cycle. Based on these results, it is suggested that the time appropriate for induction of final maturation would be from November–December to April when the testes are in the late stage of development.     

T cells in a suppressor circuit and non-T: non-B cells bear different 1-J determinants

T cells involved in the generation of suppressor activity bear an I-J-subregion controlled determinant (e. g., J₁) which is distinct from that (e. g., J₁) found on non-T: non-13 accessory cells. T-cell subsets examined include Ly-1 inducer and Ly-1,2 acceptor cells which collaborate to generate suppressor activity in the in vitro sheep red blood cell antibody system. Non-T:non-B accessory cells examined include accessory cells involved in concanavalin-A induced, T-cell proliferative responses and in in vitro antibody responses to sheep red blood cells. These results provide evidence for serologic and genetic complexity of the I-J subregion of the murine H-2 gene complex.     

A non-T: Non-B cell bears I-A,I-E,I-J,and Tla (Qa-1?) determinants

A non-T:non-B accessory cell in peritoneal washout or spleen-cell suspensions facilitates T-cell proliferative responses to the mitogen, concanavalin A. Utilizing monoclonal antibody, we show that this accessory cell bears the same I-A- and I-E-subregion controlled determinants as found on B cells. In addition, the same accessory cell bears a Tla (Qa-1?)-region and an I-J-subregion controlled determinant. This I-J determinant is also present on splenic accessory cells involved in in vitro antibody responses to sheep red blood cells. Data in a companion paper show that not all anti-I-J sera contain antibody reactive with the accessory cell, and suggest that T cells involved in the generation of suppressor activity and accessory cells bear different I-J-subregion controlled determinants.     

The disappearance rate of intraventricular bradykinin in the brain of the conscious rat

To explore the possibility that cyclic nucleotides control green algal growth and division, $\text{Chlamydomonas}$ chemostat cultures were assayed for cyclic nucleotides. Substantial qualities of cAMP were found in cells and in extracellular millieu. Most cGMP molecules were extracellular. Slowing cell growth by slowing chemostat dilution caused reversible changes in cellular morphology and cyclic nucleotide levels. During slowed growth cAMP level increased dramatically; cGMP level decreased. New cells resulting from division were not released from original cell wall.     

The role of hormones in the acquisition of sperm motility in salmonid fish.

In salmonid fish, spermatozoa taken from the testes are immotile, but acquire motility during their passage through the sperm duct. Using male masu salmon (Oncorhynchus masou), we found that gonadotropin-induced testicular production of 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17 alpha, 20 beta-DP), the oocyte maturation-inducing hormone of salmonid fish, is responsible for the acquisition of sperm motility. However, neither testosterone (T) nor 11-ketotestosterone (11-KT), the two major androgens in teleost fish, were effective. We also present evidence that 17 alpha, 20 beta-DP action is mediated through an increase in sperm duct pH, which in turn increases the cAMP content of sperm allowing the acquisition of motility.     

Ca2(+)-calmodulin-dependent protein kinase II phosphorylates various types of non-epithelial intermediate filament proteins

We have investigated the actions of Ca2(+)-calmodulin (CaM)-dependent protein kinase II on various types of non-epithelial intermediate filament proteins, vimentin, desmin, glial fibrillary acidic protein (GFAP) and neurofilament triplet proteins. Most of these filament proteins could serve as substrates. The effects of phosphorylation on the filamentous structure of vimentin were investigated in sedimentation experiments and by using electron microscopy. The amount of unassembled vimentin increased linearly with increased phosphorylation. However, the extent of the effect of phosphorylation on the potential to polymerize was also affected by the MgCl2 concentration, under conditions for reassembly. The actions of Ca2(+)-CaM-dependent protein kinase II on non-epithelial intermediate filaments under physiological conditions are given attention.