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Anderson RA; Wallace AM; Kicman AT; Wu FC 《Human reproduction (Oxford, England)》1997,12(8):1657-1662
Administration of supraphysiological doses of testosterone to normal men
causes inhibition of spermatogenesis, but while most become azoospermic,
30-55% maintain a low rate of spermatogenesis. We have investigated whether
there are differences in endogenous androgen production, of testicular and
adrenal origin, which may be related to the degree of suppression of
spermatogenesis. Thirty-three healthy Caucasian men were given weekly i.m.
injections of 200 mg testosterone oenanthate (TE), 18 became azoospermic,
while 15 remained oligozoospermic. Urinary excretion of epitestosterone, a
specific testicular product, was reduced to <10% of pretreatment values,
with no differences between the groups. Similar results were obtained for
other markers of testicular steroidogenesis. Urinary and plasma adrenal
androgens were also reduced during TE treatment: a statistically
significant decrease in both (P < 0.001 and P < 0.05 respectively)
was seen in the azoospermic but not oligozoospermic responders. These
results suggest that testicular steroidogenesis is decreased to <10% by
the administration of supraphysiological doses of exogenous testosterone.
Differences in the degree of ongoing steroidogenesis in the testis do not
appear to account for incomplete suppression of spermatogenesis, thus
differences in androgen metabolism may underlie this heterogeneous
response. A small but significant reduction in secretion of adrenal
androgens was also detectable, the relevance of which is unclear.
相似文献
5.
Since exogenous hemin has been shown to exert a variety of stimulatory effects on erythroid cells, including the augmentation of hemoglobin synthesis, we determined its effect on early stages of erythroid development by employing clonal cells assays. The addition of hemin at a concentration of 2 X 10(-4) M to cultures of normal murine marrow substantially increased the observed number of primitive BFU-E, which was in contrast to its lack of an effect on more mature erythroid colony-forming cells. This cell-specific enhancement of primitive BFU-E resulted in marrow frequencies equivalent to or exceeding those reported in the presence of "burst-promoting activity." In the presence of hemin, the number of BFU-E was also observed to be linearly related to the number of cells plated at very low plating densities, and the cell titration curve was observed to extrapolate to the origin. The evidence suggests that hemin may be a primary growth regulator of early developmental stages of erythroid progenitor cells. 相似文献
6.
Shigemoto Yoko Matsuda Hiroshi Kimura Yukio Chiba Emiko Ohnishi Masahiro Nakaya Moto Maikusa Norihide Ogawa Masayo Mukai Yohei Takahashi Yuji Sako Kazuya Toyama Hiroshi Inui Yoshitaka Taki Yasuyuki Nagayama Hiroshi Ono Kenjiro Kono Atsushi Sekiguchi Kenji Hirano Shigeki Sato Noriko 《Annals of nuclear medicine》2022,36(5):460-467
Annals of Nuclear Medicine - Although previous studies have investigated age and gender effects on striatal subregional dopamine transporter (DaT) binding, these studies were mostly based on a... 相似文献
7.
Chiang Jannifer O. Azevedo Rafael S. Justino Maria C. A. Matos Haroldo J. Cabeça Hideraldo L. S. Silva Sandro P. Henriques Daniele F. Silva Eliana V. P. Andrade Gabriela S. S. Vasconcelos Pedro FC. Martins Lívia C. Azevedo Raimunda S. S. 《Journal of neurovirology》2021,27(4):626-630
Journal of NeuroVirology - We describe two neurological cases of Oropouche virus infection in northern Brazil, where the virus is endemic but neglected as a pathogen. This study reiterates the... 相似文献
8.
Fetal persistent middle cerebral artery reversed end diastolic flow is a rare and ominous finding. Previous cases have been associated with intracranial hemorrhage, growth restriction, anaemia, and hepatic anomaly. Intrauterine demise or early neonatal death is a common outcome. We report the case of persistent middle cerebral artery reversed end diastolic flow in a well-grown fetus at 32 weeks’ gestation resulting from acute, severe anaemia due to a large feto-maternal hemorrhage. An emergency cesarean section was performed and the neonate required advanced resuscitation and immediate blood transfusion. Postnatal magnetic resonance imaging confirmed a hemorrhagic parietal infarct and bilateral ischaemic changes in the basal ganglia. This provides further evidence that persistent middle cerebral artery reversed end diastolic flow in any fetus is an ominous finding warranting urgent diagnostic evaluation and/or delivery. 相似文献
9.
A Mocroft B Neesgard R Zangerle A Rieger A Castagna V Spagnuolo A Antinori FC Lampe M Youle JJ Vehreschild C Mussini V Borghi J Begovac C Duvivier HF Gunthard A Rauch J Tiraboschi N Chkhartishvili N Bolokadze F Wit JC Wasmuth S De Wit C Necsoi C Pradier V Svedhem C Stephan K Petoumenos H Garges F Rogatto L Peters L Ryom 《HIV medicine》2020,21(9):599-606
10.
Motoi Baba Masato Takahashi Katsushige Yamashiro Hideki Yokoo Moto Fukai Masanori Sato Mitsuchika Hosoda Toshiya Kamiyama Akinobu Taketomi Hiroko Yamashita 《Surgery today》2016,46(7):843-851