Evidence for a rapid in Vivo Effect on Estradiol-17β on Prolactin Secretion in Ovariectomized Rats

1979 ◽  
Vol 6 (2) ◽  
pp. 135-148 ◽  
Author(s):  
David M. Lawson

1972 ◽  
Vol 69 (1) ◽  
pp. 141-152 ◽  
Author(s):  
A. Zmigrod ◽  
H. R. Lindner ◽  
S. A. Lamprecht

ABSTRACT Progesterone underwent extensive reductive metabolism when incubated with a microsomal preparation from rat ovaries in the presence of NADPH. The major products formed were 3β-hydroxy-5α-pregnan-20-one, 5α-pregnane-3,20-dione and 5α-pregnane-3β,20α-diol. Newly formed corpora lutea of pregnancy were almost devoid of any microsomal A-ring reducing activity (5α-reductase and a 3β-hydroxysteroid dehydrogenase) and of soluble 20α-hydroxysteroid dehydrogenase. The behaviour of the A-ring reducing enzymes paralleled that of 20α-ol dehydrogenase in that their activity (i) was high during the oestrous cycle; (ii) declined between the third and seventh day of pregnancy; and (iii) increased sharply in corpora lutea of pregnancy when ergocornine – a drug blocking pituitary prolactin secretion – was given to the rats, yet remained low when prolactin and ergocornine were administered concurrently. However, the A-ring reducing activity did not show the sharp pre-partum rise exhibited by 20α-ol dehydrogenase, thus deviating from a pattern compatible with a co-ordinate control of the three enzymes involved in the metabolic inactivation of progesterone. Contrary to a report in the literature, 5α-pregnane-3,20-dione (20 mg/rat/day) was found to be ineffective when tested for pregnancy or deciduoma supporting activity in ovariectomized rats. The microsomal reductases, if indeed operative in vivo, may restrict the availability of progesterone as an oestrogen precursor.



1984 ◽  
Vol 247 (4) ◽  
pp. E483-E488
Author(s):  
M. Haji ◽  
G. S. Roth ◽  
M. R. Blackman

Various in vivo and in vitro pituitary lactotropic and gonadotropic functions were measured in mature (6-7 mo, normally cycling) and old (24 mo, constant diestrus) female Wistar rats. Serum prolactin (PRL) levels were higher (P less than 0.001), whereas luteinizing hormone (LH) values were similar (P greater than 0.05) in old versus mature rats both before and 3 days after ovariectomy. Serum PRL levels decreased significantly (P less than 0.005) postovariectomy only in the mature rats. The in vitro release of PRL and LH was measured for 4 days in primary adenohypophyseal cell cultures from the ovariectomized rats. Both basal and 17 beta-estradiol (E2)-stimulated PRL release (P less than 0.001) and production (P less than 0.005) were greater by cells from old rats. In contrast, both basal release and E2-stimulated LH release were greater (P less than 0.001) by cells from mature rats. Peak PRL release by cells from both old and mature rats occurred after exposure to E2 doses 1/100th of those required for peak LH release. These data support the hypothesis that intrinsic derangements in anterior pituitary function contribute to the reproductive decline in aging female rats and that different pituitary cell types exhibit discordant age changes in estrogenic sensitivity.



1970 ◽  
Vol 64 (4) ◽  
pp. 687-695 ◽  
Author(s):  
Junzo Kato

ABSTRACT The anterior, middle, and posterior hypothalamus, the cortex cerebri, the anterior hypophysis as well as the diaphragm of adult ovariectomized rats were incubated in vitro with tritiated 17β-oestradiol. The uptake of tritiated oestradiol was differentially distributed intracerebrally with higher accumulation in the anterior hypothalamus and the hypophysis. Lowering the temperature of the incubation medium caused a reduction in the uptake of radioactivity by the anterior hypothalamus as compared to that found in other brain tissues. Tritiated oestradiol taken up in vitro by the anterior hypothalamus and the hypophysis tended to be retained after further incubation in a steroid-free medium. The addition of non-radioactive 17β-oestradiol to the medium inhibited the uptake of tritiated oestradiol by these tissues. Moreover, pretreatment with non-radioactive 17β-oestradiol in vivo prevented the preferential accumulation of tritiated oestradiol in vitro in the anterior hypothalamus and the hypophysis. These results indicate that oestradiol is preferentially taken up in vitro by the anterior hypothalamus and the hypophysis of the rat.



Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1033
Author(s):  
Ji Hwan Lee ◽  
Sullim Lee ◽  
Quynh Nhu Nguyen ◽  
Hung Manh Phung ◽  
Myoung-Sook Shin ◽  
...  

Estrogen replacement therapy is a treatment to relieve the symptoms of menopause. Many studies suggest that natural bioactive ingredients from plants resemble estrogen in structure and biological functions and can relieve symptoms of menopause. The fruit of V. rotundifolia, called “Man HyungJa” in Korean, is a traditional medicine used to treat headache, migraine, eye pain, neuralgia, and premenstrual syndrome in Korea and China. The aim of the present study was to confirm that V. rotundifolia fruit extract (VFE) exerts biological functions similar to those of estrogen in menopausal syndrome. We investigated its in vitro effects on MCF-7 cells and in vivo estrogen-like effects on weight gain and uterine contraction in ovariectomized rats. Using the polar extract, the active constituents of VFE (artemetin, vitexicarpin, hesperidin, luteolin, vitexin, and vanillic acid) with estrogen-like activity were identified in MCF-7 cells. In animal experiments, the efficacy of VFE in ameliorating body weight gain was similar to that of estrogen, as evidenced from improvements in uterine atrophy. Vitexin and vitexicarpin are suggested as the active constituents of V. rotundifolia fruits.



1986 ◽  
Vol 109 (2) ◽  
pp. 169-174 ◽  
Author(s):  
J. N. Hugues ◽  
A. Enjalbert ◽  
E. Moyse ◽  
C. Shu ◽  
M. J. Voirol ◽  
...  

ABSTRACT The role of somatostatin (SRIF) on adenohypophysial hormone secretion in starved rats was reassessed by passive immunization. Because of the absence of pulsatile GH secretion in starved rats, the effects of the injection of SRIF antiserum on GH levels can be clearly demonstrated. To determine whether starvation modifies the sensitivity of the adenohypophysis to SRIF, we measured 125I-labelled iodo-N-Tyr-SRIF binding. There was no difference in the dissociation constant (Kd) nor in the maximal binding capacity (Bmax) in fed (n = 15) and starved (n = 15) animals (Kd = 0·38 ± 0·09 (s.e.m.) and 0·45 ± 0·09 nmol; Bmax = 204 ± 39 and 205 ± 30 fmol/mg protein respectively). Administration of SRIF antiserum resulted in a dose-dependent increase in plasma concentrations of GH, TSH and prolactin. The minimal effective dose of SRIF antiserum was 50 μl for GH, 100 μl for TSH and 200 μl for prolactin. Our results show that: (1) starvation does not modify adenohypophysial SRIF-binding sites, (2) in starved male rats endogenous SRIF exerts a negative control on prolactin secretion in vivo and (3) sensitivity to endogenous SRIF seems to be different for each hypophysial cell type. J. Endocr. (1986) 109, 169–174



1993 ◽  
Vol 22 (3) ◽  
pp. 209-220 ◽  
Author(s):  
Dike N. Kalu ◽  
Elena Salerno ◽  
Yoshikazu Higami ◽  
Chung Ching Liu ◽  
Fabrizio Ferraro ◽  
...  


2018 ◽  
Vol 52 (5) ◽  
pp. 479-489 ◽  
Author(s):  
Sebastian T Müller ◽  
Annekathrin M Keiler ◽  
Kristin Kräker ◽  
Oliver Zierau ◽  
Ricardo Bernhardt

Bone protection and metabolism are directly linked to estrogen levels, but exercise is also considered to have bone protective effects. Reduced estrogen levels lead to a variety of disorders, for example, bone loss and reduced movement drive. The objective of this study was to investigate the effects of estrogen on individual voluntary exercise motivation and bone protection. We investigated sham operated, ovariectomized, and ovariectomized with estrogen supplemented Wistar rats (20 weeks old) either with or without access to exercise wheels. We selected an experimental approach where we could monitor the individual exercise of group-housed rats with ad libitum access to a running wheel with the help of a subcutaneous chip. In vivo and ex vivo microcomputed tomography analyses of the tibia were performed at two-week intervals from week 0 to week 6. Furthermore, tibial trabecular structure was evaluated based on histomorphometric analyses. We observed a significant bone protective effect of E2. For exercise performance, a substantially high intra-group variability was observed, especially in the E2 group. We presume that dominant behavior occurs within the group-housed rats resulting in a hierarchical access to the running wheel and a high variability of distance run. Exercise did not prevent ovariectomy-induced bone loss. However, lack of estrogen within the ovariectomized rats led to a drastically reduced activity prevented by estrogen supplementation. Our findings are important for future studies working with group-housed rats and exercise. The reason for the high intra-group variability in exercise needs to be investigated in future studies.



2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
J Moyer ◽  
D Dunj. Baston-Buest ◽  
G Wennemuth ◽  
A Bielfeld ◽  
R Grümmer

Abstract Study question Which compounds/compound combinations are most effective in decidualization induction of endometrial stromal cells (ESCs) of patients with and without endometriosis? Summary answer Combination of compounds addressing different steps in the signalling cascade of decidualization induce decidualization more effectively than application of the individual compounds alone. What is known already Decidualization is the monthly recurring differentiation process of the ESCs in preparation for embryo implantation in human. Undifferentiated ESCs reveal an increased potential to proliferate and invade after retrograde menstruation. This may lead to the formation of ectopic lesions and the manifestation of the chronic gynaecological disease of endometriosis due to an impairment of the decidualization process. Study design, size, duration Compounds and compound combinations addressing the progesterone receptor- or the cAMP-mediated pathway were evaluated with regard to their own and their synergistic potential to induce decidualization of ESCs from women with (n = 10) and without (n = 10) endometriosis during a 6-day treatment. Participants/materials, setting, methods Human primary ESCs were isolated via enzymatic-mechanic digestion from eutopic endometrium from women with and without endometriosis and treated for 6 days in vitro with different progestins (progesterone, medoxyprogesterone acetate (MPA)), 8-Br-cAMP, forskolin, or phosphodiesterase (PDE)-inhibitor (Rolipram) alone or in combination. The degree of decidualization induction was quantified by morphological, biochemical (prolactin) and molecular (HAND2, FOXO1) parameters by means of ELISA, flow cytometric analysis, Realtime PCR and Western blot analysis. Main results and the role of chance After 6 days of treatment, decidualization was induced by forskolin as well as by 8-Br-cAMP whereas progestins or PDE alone hardly induced prolactin secretion by ESCs as a marker of decidualization. A change of morphology from undifferentiated fibroblast-like cells to rounded cells could be observed in parallel with the secretion of prolactin. Forskolin and 8-Br-cAMP-induced decidualization was significantly enhanced by MPA but not by progesterone. These effects were similar in ESCs from women with and without endometriosis. Moreover, forskolin-induced decidualization was significantly enhanced by simultaneous application of PDE. Interestingly, this effect was higher in cells of patients with endometriosis. An induction of decidualization in ESCs was associated with a parallel increase of the process-associated transcription factors HAND2 and FOXO1. This rise of transcription was markedly increased in combination with MPA but not with progesterone. Limitations, reasons for caution Endometrial tissue was obtained from women undergoing infertility treatment and thus may differ from the endometrium of fertile women. Results obtained from primary cells in vitro may not cover the in vivo situation in all respects. Wider implications of the findings: The results of this study provide baseline data for the development of a possible therapeutical approach to induce decidualization as a treatment option for endometriosis. Further research is required to determine the effectiveness of the in vitro tested compound combinations in an in vivo model. Trial registration number Not applicable



2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
J Moyer ◽  
D Dunja Baston-Buest ◽  
G Wennemuth ◽  
A Bielfeld ◽  
R Grümmer

Abstract Study question Which compounds/compound combinations are most effective in decidualization induction of endometrial stromal cells (ESCs) of patients with and without endometriosis? Summary answer Combination of compounds addressing different steps in the signalling cascade of decidualization induce decidualization more effectively than application of the individual compounds alone. What is known already Decidualization is the monthly recurring differentiation process of the ESCs in preparation for embryo implantation in human. Undifferentiated ESCs reveal an increased potential to proliferate and invade after retrograde menstruation. This may lead to the formation of ectopic lesions and the manifestation of the chronic gynaecological disease of endometriosis due to an impairment of the decidualization process. Study design, size, duration Compounds and compound combinations addressing the progesterone receptor- or the cAMP-mediated pathway were evaluated with regard to their own and their synergistic potential to induce decidualization of ESCs from women with (n = 10) and without (n = 10) endometriosis during a 6-day treatment. Participants/materials, setting, methods Human primary ESCs were isolated via enzymatic-mechanic digestion from eutopic endometrium from women with and without endometriosis and treated for 6 days in vitro with different progestins (progesterone, medoxyprogesterone acetate (MPA)), 8-Br-cAMP, forskolin, or phosphodiesterase (PDE)-inhibitor (Rolipram) alone or in combination. The degree of decidualization induction was quantified by morphological, biochemical (prolactin) and molecular (HAND2, FOXO1) parameters by means of ELISA, flow cytometric analysis, Realtime PCR and Western blot analysis. Main results and the role of chance After 6 days of treatment, decidualization was induced by forskolin as well as by 8-Br-cAMP whereas progestins or PDE alone hardly induced prolactin secretion by ESCs as a marker of decidualization. A change of morphology from undifferentiated fibroblast-like cells to rounded cells could be observed in parallel with the secretion of prolactin. Forskolin and 8-Br-cAMP-induced decidualization was significantly enhanced by MPA but not by progesterone. These effects were similar in ESCs from women with and without endometriosis. Moreover, forskolin-induced decidualization was significantly enhanced by simultaneous application of PDE. Interestingly, this effect was higher in cells of patients with endometriosis. An induction of decidualization in ESCs was associated with a parallel increase of the process-associated transcription factors HAND2 and FOXO1. This rise of transcription was markedly increased in combination with MPA but not with progesterone. Limitations, reasons for caution Endometrial tissue was obtained from women undergoing infertility treatment and thus may differ from the endometrium of fertile women. Results obtained from primary cells in vitro may not cover the in vivo situation in all respects. Wider implications of the findings The results of this study provide baseline data for the development of a possible therapeutical approach to induce decidualization as a treatment option for endometriosis. Further research is required to determine the effectiveness of the in vitro tested compound combinations in an in vivo model. Trial registration number not applicable



Sign in / Sign up

Export Citation Format

Share Document