Ovaries stimulants

P3. Pampfer, S., Vankrieken, L., Loumaye, E., De Hertogh, R., and Thomas, K., Inhibin and renin in follicular fluids of patients with one or two ovaries stimulated with a GnRH agonist and gonadotrophins. Hum. Reprod. 4, 396-402 (1989). 

F ollicle-stimulating hormone (FSFl) Anterior pituitary In ovaries, stimulates ovulation and estrogen synthesis in testes, stimulates spermatogenesis... 

P and Pg, exist in foUicular fluid. Control of inhibin secretion involves a feedback relationship in which circulating FSH stimulates inhibin secretion, which in turn reduces the secretion of FSH (8). Both the homo- and the heterodimers of the P-subunits of inhibin promote the secretion of FSH and thus have been termed activins. Activin is secreted by the ovary and the testes into the circulation. In addition, both inhibin and activin have intragonadal autocrine and paracrine effects that influence gonadal steroidogenesis (9). 

Estrogens stimulate cellular proliferation, induce RNA and protein synthesis of uterine endometrium and the fibrous connective tissue framework for ovaries, and increase the size of the cells. This effect leads to the growth and regeneration of the endometrial layer and spinal arterioles, and increase in the number and size of endometrial glands. Under the influence of estrogen, vaginal mucosa becomes thicker, as cervical mucus becomes thinner (85,86). 

Prolactin is peptide hormone secreted by the pituitary gland. It acts on prolactin receptors in breast tissue where it stimulates production of casein and lactalbu-min. It also acts on the testes and ovaries to inhibit the effects of gonadotrophins. Since the secretion of prolactin is under tonic dopaminergic inhibition by the hypothalamus, dopamine D2-receptor antagonists... 

The gonadotropins, follicle-stimulating hormone and luteinizing hormone, exert their effects on the gonads (ovaries in the female and testes in the male). Taken together, the gonadotropins stimulate the gonads to ... 

The evidence for 20-hydroxyecdysone stimulating sex pheromone production in the housefly comes from both direct and indirect studies. A correlation was found between ovarian development and sex pheromone production in female flies [236,237]. Surgical removal of ovaries immediately after adult emergence resulted in no sex pheromone production, whereas allatectomized (which removes the source of JH production) females produced the same amount of pheromone as did normal females [238,239]. Additionally, ovariectomized females that received ovary implants produced sex pheromone [238]. These data demonstrate that 20-hydroxyecdysone and not JH regulates pheromone production in the housefly [111]. 

Additional evidence came from the finding that sex pheromone production could be stimulated in male houseflies that do not normally produce detectable sex pheromone components. Male houseflies were found to have longer chain alkenes, Z9-27 H,but did not have Z9-23 H. Implantation of ovaries into male houseflies resulted in a change in hydrocarbon biosynthesis such that the longer chain alkenes were not made but rather they produced the shorter chain length Z9-23 H [240]. Likewise, injection of 20-hydroxyecdysone into males induced sex pheromone production in a dose-dependent manner. These studies demonstrated that males possess the biosynthetic capability to produce sex pheromone, but normally do not produce the 20-hydroxyecdysone necessary to induce sex pheromone production. Males became an excellent model in which to study the hormonal regulation of pheromone biosynthesis in the housefly. 

Expression of the cloned receptors in Chinese hamster ovary cells, other mammalian cells and Xenopus oocytes has demonstrated differential coupling of these receptors to cellular responses. In general the Mb M3 and M5 receptors regulate phosphoinositide hydrolysis by stimulating PLC. This occurs through selective coupling of the receptor to the pertussis-toxin-insensitive G protein Gq/11,... 

The selectivity in muscarinic receptor coupling is not, however, absolute. Overexpression of receptors or of particular G proteins supports interactions that may differ from those described above. For example, M2 receptors expressed in Chinese hamster ovary cells not only inhibit adenylyl cyclase but also can stimulate phosphoinositide hydrolysis through a pertussis-toxin-sensitive G protein [52] this is not seen, however, when M2 receptors are expressed in Y1 cells. These findings indicate that caution must be exercised in interpreting data obtained when receptors are expressed, often at high levels, in cells in which they normally do not function. 

In preclinical models, arzoxifene exerts an estrogen agonistic effect on bone and on the lipid profile and an estrogen antagonistic effect in breast and endometrium (Sato et al. 1998 Russo et al. 1990 Ma et al. 1998). Thus, in both the ovariectomized rat and the ovary-intact rat arzoxifene did not stimulate uterine weight gain (Russo et al. 1990). 

Low concentrations (10 /iM or less) of mercury have little effect on cellular viability and stimulate RNA and DNA synthesis, whereas higher concentrations are cytotoxic and inhibit DNA, RNA and protein synthesis [145, 146, 246-248 ]. Mercuric chloride is able to selectively block CHO (Chinese hamster ovary) cells in S phase, which is related to the chemical reactivity and uptake into the cells [249], The cytotoxicity of mercury(II) compounds is probably related to their ability to inhibit DNA polymerase a activity and inhibit not only DNA synthesis but also DNA repair [250, 251]. 

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