scholarly journals Effect of neonatal exposure to estrogenic compounds on development of the excurrent ducts of the rat testis through puberty to adulthood.

1999 ◽  
Vol 107 (5) ◽  
pp. 397-405 ◽  
Author(s):  
J S Fisher ◽  
K J Turner ◽  
D Brown ◽  
R M Sharpe
2006 ◽  
Vol 91 (2) ◽  
pp. 456-466 ◽  
Author(s):  
Tiina F. M. Mikkilä ◽  
Jorma Toppari ◽  
Jorma Paranko
Keyword(s):  

2000 ◽  
Vol 165 (2) ◽  
pp. 345-357 ◽  
Author(s):  
M Tena-Sempere ◽  
J Navarro ◽  
L Pinilla ◽  
LC Gonzalez ◽  
I Huhtaniemi ◽  
...  

The biological actions of estrogens on target cells are mediated by two nuclear receptors: the estrogen receptor (ER) alpha and the recently characterized ER beta. In the male rat, the physiological role of estrogens involves multiple actions, from masculinization of brain areas related to reproductive function and sexual behavior to regulation of testicular development and function. Paradoxically, however, administration of high doses of estrogen during the critical period of neonatal differentiation results in an array of defects in the reproductive axis that permanently disrupt male fertility. The focus of this study was to characterize the effects and mechanism(s) of action of neonatal estrogenization on the pattern of testicular ER alpha and beta gene expression during postnatal development. To this end, groups of male rats were treated at day 1 of age with estradiol benzoate (500 microg/rat), and testicular ER alpha and ER beta mRNA levels were assayed by semi-quantitative RT-PCR from the neonatal period until puberty (days 1-45 of age). Furthermore, the expression of androgen receptor (AR) mRNA was evaluated, given the partially overlapping pattern of tissue distribution of ER alpha, ER beta and AR messages in the developing rat testis. In addition, potential mechanisms for neonatal estrogen action were explored. Thus, to discriminate between direct effects and indirect actions through estrogen-induced suppression of serum gonadotropins, the effects of neonatal estrogenization were compared with those induced by blockade of gonadotropin secretion with a potent LHRH antagonist in the neonatal period. Our results indicate that neonatal exposure to estrogen differentially alters testicular expression of alpha and beta ER messages: ER alpha mRNA levels, as well as those of AR, were significantly decreased, whereas relative and total expression levels of ER beta mRNA increased during postnatal/prepubertal development after neonatal estrogen exposure, a phenomenon that was not mimicked by LHRH antagonist treatment. It is concluded that the effect of estrogen on the expression levels of ER alpha and beta mRNAs probably involves a direct action on the developing testis, and cannot be attributed to estrogen-induced suppression of gonadotropin secretion during the neonatal period.


2006 ◽  
Vol 175 (4S) ◽  
pp. 521-521
Author(s):  
Motoaki Saito ◽  
Tomoharu Kono ◽  
Yukako Kinoshita ◽  
Itaru Satoh ◽  
Keisuke Satoh

1988 ◽  
Vol 117 (4_Suppl) ◽  
pp. S36-S37 ◽  
Author(s):  
F. PARIS ◽  
P. LEMBKE ◽  
R. SCHULZ ◽  
V. BLÜM
Keyword(s):  

2014 ◽  
Vol 2 (2) ◽  
pp. 56
Author(s):  
Elçin Hakan Terzi ◽  
Aysel Kükner ◽  
Serkan Öztürk ◽  
Candan Özoğul ◽  
Uğur Üyetürk

Author(s):  
Н.Н. Хлебникова ◽  
Н.А. Крупина

В наших предыдущих исследованиях было показано, что ингибитор пролинспецифической пептидазы дипептидилпептидазы-IV (ДП-IV, EC 3.4.14.5) трипептид дипротин А, введенный крысам в 5-18 постнатальные дни, приводит к развитию у крыс подросткового возраста и взрослых животных эмоционально-мотивационных расстройств. Такие расстройства можно рассматривать как модель смешанного тревожно-депрессивного состояния. Однако специальных исследований по валидности данной модели проведено не было. Цель настоящей работы состояла в проверке влияния трициклического антидепрессанта имипрамина (ИМИ) на депрессивноподобное поведение крыс и уровень кортикостерона в сыворотке крови животных на модели смешанного тревожно-депрессивного состояния. Методика. У крыс в возрасте одного и двух мес. определяли уровень тревожности в автоматизированном тесте «Приподнятый крестообразный лабиринт» и оценивали депрессивноподобное поведение в тесте принудительного плавания. ИМИ вводили взрослым животным в течение 10 дней (20 мг/кг/день, интрагастрально). Уровень кортикостерона в сыворотке крови определяли методом твердофазного иммуноферментного анализа. Результаты. Неонатальное действие дипротина А приводило к повышению тревожности у крыс в возрасте 1 мес. Депрессивноподобное поведение обнаружено у животных в возрасте одного и двух мес. ИМИ нормализовал поведение животных в тесте принудительного плавания и снижал уровень кортикостерона в сыворотке крови крыс. Кроме того, ИМИ снижал вес крыс. Заключение. Результаты исследования свидетельствуют в пользу адекватности модели смешанного тревожно-депрессивного расстройства, возникающего у крыс вследствие действия ингибитора ДП-IV дипротина А на второй-третьей неделях постнатального развития, клиническому прообразу заболевания по критериям «внешней схожести», прогностической и конструкционной валидности. Previously, we have shown that the inhibitor of proline-specific peptidase, dipeptidyl peptidase-IV (DP-IV, EC 3.4.14.5), tripeptide diproptin A administered on postnatal days 5-18 induced emotional and motivational disorders in adolescent and adult rats. These disorders can be considered a model of a mixed anxiety-depression-like disorder. However, validation studies of this model are not available. The aim of this work was to test the effect of the tricyclic antidepressant, imipramine (IMI), on depressive-like behavior in rats and the level of serum corticosterone using the model of mixed anxiety-depressive state. Methods. The level of anxiety was assessed by the automated Elevated Plus Maze test and the depressive-like behavior was evaluated by the forced swimming test in one- and two-month old rats. IMI was administered to adult animals for ten days (20 mg/kg a day, intragastrically). Serum corticosterone concentrations were measured using ELISA. Results. The neonatal exposure to diprotin A increased anxiety in one-month old rats. The depressive-like behavior was observed in animals aged one and two months. IMI normalized behavior of animals in the forced swimming test and reduced serum levels of corticosterone. Also, IMI reduced body weight of rats. Conclusion. The results of the study evidenced adequacy of the model of mixed anxiety-depressive state induced by the DP-IV inhibitor, diprotin A, on the second and third postnatal weeks to the clinical prototype of disease according to criteria of face validity, predictive and construct validity.


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