Liza O'Donnell

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Although it has been known for many years that estrogen administration has deleterious effects on male fertility, data from transgenic mice deficient in estrogen receptors or aromatase point to an essential physiological role for estrogen in male fertility. This review summarizes the current knowledge on the localization of estrogen receptors and aromatase(More)
It is well established that spermatogenesis is controlled by gonadotrophins and testosterone. However, a role for estrogens in male reproduction recently was suggested in adult mice deficient in estrogen receptor alpha. These mice became infertile primarily because of an interruption of fluid reabsorption by the efferent ductules of the epididymis, thus(More)
A detailed understanding of the hormonal regulation of spermatogenesis is required for the informed assessment and management of male fertility and, conversely, for the development of safe and reversible male hormonal contraception. An approach to the study of these issues is outlined based on the use of well-defined in vivo models of gonadotropin/androgen(More)
Testosterone (T) has been shown to be essential for the completion of spermiogenesis. Our previous studies showed that when intratesticular T was suppressed for 11 wk, the conversion of round spermatids between stages VII and VIII of the spermatogenic cycle was markedly suppressed and that elongated spermatids were undetectable. The fate of the round(More)
Testosterone (T) treatment suppresses gonadotropin levels and sperm counts in normal men, but the addition of a progestin may improve the efficacy of hormonal contraception. This study aimed to investigate the speed and extent of suppression of testicular germ cell number induced by T plus or minus progestin treatment and correlate these changes with serum(More)
Several spermatogenic cell types have been reported to be responsive to testosterone (T) in vivo. We have proposed that the principal action of T is to facilitate the maturation of round to elongated spermatids during spermiogenesis. To identify T-dependent cell types during spermiogenesis, round spermatid populations were counted using stereological(More)
The Sertoli cell ectoplasmic specialization is a unique junctional structure involved in the interaction between elongating spermatids and Sertoli cells. We have previously shown that suppression of testicular testosterone in adult rats by low-dose testosterone and estradiol (TE) treatment causes the premature detachment of step 8 round spermatids from the(More)
The isolation and molecular analysis of highly purified cell populations from complex, heterogeneous tissues has been a challenge for many years. Spermatogenesis in the testis is a particularly difficult process to study given the unique multiple cellular associations within the seminiferous epithelium, making the isolation of specific cell types difficult.(More)
At the end of spermatogenesis, elongated spermatids are released from supporting Sertoli cells via the process termed spermiation. Previous studies have shown that spermiation failure occurs after hormone suppression, in which spermatids are retained instead of releasing. However, the molecular mechanisms involved in spermiation and spermiation failure are(More)