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Low-dose human chorionic gonadotropin maintains intratesticular testosterone in normal men with testosterone-induced gonadotropin suppression
(Endocrine Society, 2005-05)
In previous studies of testicular biopsy tissue from healthy men,
intratesticular testosterone (ITT) has been shown to be much higher than
serum testosterone (T), suggesting that high ITT is needed relative to
serum T for normal spermatogenesis in men. However, the quantitative
relationship between ...
Male hormonal contraception: effects of injections of testosterone undecanoate and depot medroxyprogesterone acetate at eight-week intervals in chinese men
(Endocrine Society, 2004-05)
Surveys indicate that one form of acceptable male hormonal contraception
would consist of injections given at 2- to 3-month intervals. This report
describes a study of depot medroxyprogesterone acetate (DMPA) and
testosterone undecanoate (TU) injected at 8-wk intervals for suppression
of spermatogenesis ...
Immature spermatids are not prevalent in semen from men who are receiving androgen-based contraceptive regimens
(Elsevier, 1998-01)
OBJECTIVE: To determine whether immature spermatids increase in semen in
response to hormonal contraceptive treatments. Such a finding would
support the existence of a defect in spermiogenesis, which in turn may
explain the reported variability in sperm output. DESIGN: Semen smears
were obtained ...
Ovarian follicular concentrations of activin, follistatin, inhibin, insulin-like growth factor I (IGF-I), IGF-II, IGF-binding protein-2 (IGFBP-2), IGFBP-3, and vascular endothelial growth factor in spontaneous menstrual cycles of normal women of advanced reproductive age
(Endocrine Society, 2000-12)
Previous studies indicate that the menstrual cycles of older reproductive
age women are characterized by a selective elevation of FSH associated
with early development and ovulation of a dominant follicle. Several
intraovarian hormones and growth factors have been identified that appear
to serve ...
Male hormonal contraception: suppression of spermatogenesis by injectable testosterone undecanoate alone or with levonorgestrel implants in chinese men
(American Society of Andrology, 2004-09)
Monthly injections of testosterone undecanoate (TU) act as a male
contraceptive by reversibly suppressing spermatogenesis to azoospermia or
severe oligoazoospermia in 95% of Chinese men. In 5% of Chinese men,
however, monthly TU administered alone fails to suppress spermatogenesis
into contraceptive ...
A clinical trial of injectable testosterone undecanoate as a potential male contraceptive in normal Chinese men
(Endocrine Society, 1999-10)
This is a pilot dose-finding study of spermatogenic suppression using
testosterone undecanoate (TU) injections alone in normal Chinese men.
Thirty-two healthy men were recruited. Volunteers underwent pretreatment
evaluation, then a treatment period in which group I (n = 13) received 500
mg TU, group ...
Age-related analysis of inhibin A, inhibin B, and activin a relative to the intercycle monotropic follicle-stimulating hormone rise in normal ovulatory women
(Endocrine Society, 2004-06)
Previous studies have reported that the monotropic rise in FSH in older
women is associated with decreased inhibin B and/or A levels and increased
levels of activin A. Whereas most investigators have found decreased
follicular-phase inhibin B, the roles of inhibin A and activin A as
modulators of ...
Reproductive ageing and ovarian function: is the early follicular phase FSH rise necessary to maintain adequate secretory function in older ovulatory women?
(Oxford University Press, 2005-01)
BACKGROUND: Serum FSH elevations and decreases in inhibin B have been
consistently demonstrated in the early follicular phase of cycles in women
of advanced reproductive age. However, secretory products of the dominant
follicle (estradiol and inhibin A) in the serum of older ovulatory women
are ...
Daily testosterone and gonadotropin levels are similar in azoospermic and nonazoospermic normal men administered weekly testosterone: implications for male contraceptive development
(American Society of Andrology, 2001-11)
Weekly intramuscular administration of testosterone esters such as
testosterone enanthate (TE) suppresses gonadotropins and spermatogenesis
and has been studied as a male contraceptive. For unknown reasons,
however, some men fail to achieve azoospermia with such regimens. We
hypothesized that either ...
The effects of aging in normal men on bioavailable testosterone and luteinizing hormone secretion: response to clomiphene citrate
(Endocrine Society, 1987-12)
Serum testosterone (T) levels in men decline with age while serum LH
levels, as measured by RIA, increase. To assess if the decline in serum T
levels in healthy aging men is paralleled by an age-related decline in the
bioavailable non-sex hormone-binding globulin (SHBG)-bound fraction of T
and to ...