Effects of Intranasally Administered Insulin and Gangliosides on Metabolic Parameters and Activity of the Hepatic Insulin System in Rats with Type 2 Diabetes Mellitus

Journal of Evolutionary Biochemistry and Physiology - Insulin regulates glucose metabolism via both direct hormone interactions with its signaling system and glucose transporters in cells of...     

Insulin and Brain Gangliosides Prevent Metabolic Disorders Caused by Activation of Free Radical Reactions after Two-Vessel Ischemia–Reperfusion Injury to the Rat Forebrain

Journal of Evolutionary Biochemistry and Physiology - The ability of insulin and gangliosides, administered separately or jointly, to increase the viability of cultured brain cortical neurons under...     

The effect of four C21-steroids on oocyte maturation in Siberian sturgeon (<Emphasis Type="Italic">Acipenser baeri</Emphasis> Brandt)

The effect of four C21-steroids, progesterone (P₄), 17,20β-dihydroxy-4-pregnen-3-one (17,20βP), 17,20β,21-trihydroxy-4-pregnen-3-one (20βS) and 11-desoxycortisol (S), on in vitro oocyte maturation in Siberian sturgeon (Acipenser baeri Brandt) females was demonstrated using short-term (5 and 30 min) exposures of ovarian follicles to steroid solutions followed by incubation in steroid-free medium. The study aimed to find out which of the four candidates for a maturationinducing steroid (P₄, 17,20βP, 20βS or S) induces a fastest germinal vesicle breakdown (GVBD) in oocytes of Siberian sturgeon. Dissolution of the oocyte nucleus or GVBD was taken as a criterion of oocyte maturation. Dose-response profiles of hormone activities as well as effects of the hormones under short-term exposures of follicles to their equal doses were compared. P₄ was found to be a most active GVBD inducer compared to other C21-steroids, S was the second in its activity, whereas 17,20βP and 20βS were less efficient. A comparison of the present and previously obtained data on the dynamics of C21-steroids in vivo and their effect on ovarian follicles in vitro indicates an important role of the above hormones, particularly P₄ and 20βS, in the regulation of the final stage of oocyte maturation in sturgeons.     

The effect of hormonal stimulation on steroid levels in tissue incubates of the sterlet (<Emphasis Type="Italic">Acipenser ruthenus</Emphasis> L.)

Sex steroid and cortisol levels were compared in Leibovitz’s L-15 cultural medium after incubation of tissue samples from the intact female and male sterlet (Acipenser rhutenus L.) and from the fishes exposed to hormonal stimulation of sexual maturation by a superactive analog of mammalian gonadotropin-releasing hormone (LH-RH-A). A higher level of 17,20β,21-trihydroxy-4-pregnen-3-one (20βS) was revealed in the cultural medium following incubation of ovarian follicles isolated from females 5 h after LH-RH-A stimulation, as compared to the data obtained for intact females. The addition of 1 μM progesterone (P₄) to the cultural medium before incubation of ovarian follicles also led to an increase in the 20βS level in the incubates by the end of the experiment. Cortisol and testosterone levels in the incubates exhibited the same tendency. The blood cortisol level significantly increased in females 5 h after their hormonal stimulation. In males, showing high levels of androgens (testosterone and 11-ketotestosterone) in the blood serum before hormonal stimulation, high levels of these hormones were also detected in the cultural medium after incubation of testicular and liver tissue samples. The addition of P₄ to the medium before incubation stimulated the production of sex steroids and cortisol by the gonadal fragments. Upon addition of P₄ to the incubation mixture, containing liver tissue samples, the 20βS level increased.     

Effects of stress on serum Cortisol levels of sturgeon in aquaculture

Increased holding time in ponds or tanks of captured sturgeon broodstock can affect serum Cortisol levels, with atrend towards lower levels with increased time. A relationship between Cortisol levels and gamete quality was observed in some females, whereby low Cortisol was linked to poor gamete quality.