ABSTRACT
BACKGROUND: FSH is a heterodimeric glycoprotein and is composed of alpha and beta subunits. alpha subunit is common to FSH and LH, while an unique beta subunit determines the biological specificity of each hormone. The synthesis of beta subunit is the primary rate-limiting step in the synthesis of each hormone. Although FSH plays a pivotal role in folliculogenesis and ovulation, very little studies have been performed on the regulation of FSH beta gene expression. Therefore, the present study attempted to examine the effect of GnRH or activin on the expression of FSH beta mRNA as well as FSH release and signaling pathway involved in their actions. METHODS: The primary cultures of rat anterior pituitary were used for this study. To determine FSH beta mRNA levels, northern blotting method was used. The concentration of FSH in the culture medium was evaluated by using a specific radioimmunoassay for rat FSH. RESULTS: PMA, an activator of PKC, increased FSH beta mRNA levels and FSH release, whereas forskolin, an activator of adenylate cyclase, showed no effect. The application of GnRH augmented FSH release, but not FSH beta mRNA levels. However, the administration of activin increased FSH beta mRNA levels as well as FSH release. Staurosporine, an inhibitor of PKC, suppressed activin-induced increment of FSH beta mRNA levels and FSH release. CONCLUSION: The present study demonstrated that activin rather than GnRH is a major regulator for FSH beta mRNA expression, and suggest that PKC-dependent pathway is also involved in the action of activin on the expression of FSH beta mRNA and FSH release.
Subject(s)
Animals , Female , Rats , Activins , Adenylyl Cyclases , Blotting, Northern , Colforsin , Follicle Stimulating Hormone , Follicle Stimulating Hormone, beta Subunit , Gene Expression , Glycoproteins , Gonadotropin-Releasing Hormone , Ovulation , Radioimmunoassay , RNA, Messenger , Sensitivity and Specificity , StaurosporineABSTRACT
No Abstract Available.
ABSTRACT
Backgroand: In our previous study, it was demonstrated that estradiol-dependent prostaglandin synthesis may be mediated by cAMP elevation during the process of iplantation in rats. The present study was undertaken to investigate if estradio1, a hydrophobic molecule could interact with uterine plasma membrane, thereby influencing adenylate cyclase and cAMP. Methods: The specific binding of [3H]estradiol to plasma membrane prepared from rat uterus has been identified and characterized. Results: The association of [3H]estradiol to plasma membrane preparations reached equilibrium at 24 hrs. [3H]estradiol binding was directly proportional to the concentration of plasma membrane preparations and its binding was temperature-sensitive. This binding was saturable, reversible and binding site was one type with high affinity(Kd=0.16+0.03 nM) and high binding capacity(Bmax= 2.03 + 0.38pmol/mg protein). The dissociation constant was estimated as 1.6*10(-10)M. In a competition assay, binding was specific for estrogenic compounds. When 100% specific binding was detennined in the presence of 3*10(-6) M diethylstilbestrol, 17B-estradiol and tamoxifen displaced specific binding by 115% and 23%, respectively. Neither progesterone nor cortisol at 500-fold excess displaced the specific binding. Conclusion: These data suggest the presence of specific binding sites on the plasma membrane for estradiol in the rat uterus.
Subject(s)
Animals , Rats , Adenylyl Cyclases , Binding Sites , Cell Membrane , Diethylstilbestrol , Estradiol , Estrogens , Hydrocortisone , Membranes , Progesterone , Signal Transduction , Tamoxifen , UterusABSTRACT
No abstract available.
Subject(s)
Humans , Estrogens , Pituitary Neoplasms , Receptors, EstrogenABSTRACT
The neuroendocrine responses to surgical stress in man include release of ACTH, GH and prolactin in the serum(Cooper and NElson, 1962: Ney et al., 1963: Ross et al., 1966: Schlach, 1967: Gordon et al., 1972: Jeffrey et al., 1977). Data on serum LH and FSH during operation under general anesthesia have been conflictiong. Evidence has also been accumulated that serum LH levels are increased significantly in male patients during operation under general anesthesia in comparison of serum LH in males might be different from that in postmenopausal females with a very high basal level of LH and from menstrating females. Effects of surgical stress under general anesthesia with halothane-N2O on serum LH and FSH levels were studied in 12 menstruating female patients, 8 postmenopausal female patients, and in 8 male patients with no endocrine disorders, liver or kidney function impairment as judged by routine tests. Control serum samples were taken immediately before anesthesia and subsequent samples were obtained from the patients 30 minutes, 1hour and 5~6hours after the onset of anesthesia and on the second and seventh postoperative day. The concentrations of serum LH and FSH were measured by a specific and sensitive radioimmunoassay method. The results are as follows; 1) Preanesthetic levels of serum LH and FSH served as controls and were within range of normal values for male and female subjects in our laboratory. 2) In male patients, serum LH levels 1 hour after onset of anesthesia increased significantly over those of preanesthesia, while no significant intraoperative increase in LH levels was found in female patinets. 3) No significant change in serum LH levels was demonstrated on the second and seventh postoperative day except female patients, who showed significant decrease in the serum LH level on the second postoperative day. 4) No significant intracperative and postoperative changes in serum FSH levels were observed in male or female patients. From the above results, it may be concluded that significant intraopertive increase in serum LH levels occurs in male patients but not in female patients.