No effective hormonal contraceptive has yet been devised for men. Through their suppressive effect on gonadotropin secretion, GnRH antagonists inhibit both testosterone (T) production and spermatogenesis in animals. Long term administration of an antagonist alone would result in androgen deficiency; ...

The concentration of lipoprotein(a) [Lp(a)] in human plasma is largely genetically determined and is inversely correlated to the size of apolipoprotein(a) [apo(a)]. Additionally, Lp(a) values are relatively stable within individuals and are only marginally susceptible to therapeutic treatment. The ...

OBJECTIVE: To evaluate the ability the Nal-Lys GnRH antagonist ([N-Ac-Nal (2)1, 4ClDPhe2, D3Pal3, Lys (Nic)5, D-Lys(Nic)6, Lys (iPr)8, D-Ala10] to suppress gonadotropins and T in humans and to assess its duration of action and its local effects. DESIGN: Placebo-controlled clinical study. SETTING: ...

In men, administration of exogenous testosterone (T) exerts direct negative feedback effects at the pituitary as well as at the hypothalamic level. This study was undertaken to determine whether T itself causes the inhibitory effects on the pituitary, or whether conversion to estradiol (E2) or ...

In addition to their use as replacement therapy for hypogonadal males, androgens, particularly testosterone (T), are being explored as potential hormonal male contraceptive agents, alone or in combination with other compounds. Androgens have regulatory effects on a variety of physiological systems ...

Premenopausal women have a lower risk of coronary artery disease than men or postmenopausal women; estrogens are thought to contribute to this lower risk. Administration of exogenous estrogen to post-menopausal women increases plasma high density lipoprotein (HDL) cholesterol and may reduce mortality ...

The importance of androgens in establishing and maintaining sexual function in males of most species is well recognized. Estrogens also stimulate male sexual function in some species. In men, most studies of androgen effects on behavior have used hypogonadal men as an experimental model; much less ...

Efforts to develop a hormonal contraceptive regimen for men have focused on administration of testosterone (T), alone or together with other agents. Previous regimens have successfully induced azoospermia in only 50-70% of subjects, however. GnRH antagonists, alone or in combination with T, have ...

In women, chronic and intense endurance exercise is frequently associated with menstrual cycle alterations. In men, the effects of similar amounts of exercise are less well-studied. We tested the hypothesis that endurance exercise in men is also associated with alterations in reproductive function. ...

OBJECTIVE: To test the hypothesis that over a 4-week treatment period, Nal-Glu GnRH antagonist ([AcD2Nal1, D4ClPhe2, D3Pal3, Arg5, DGlu6 [AA], DAla10] GnRH) at a dose of 200 micrograms/kg per day SC would suppress levels of immunologically active and biologically active LH and FSH more completely ...