Testosterone release

In mice, strange females or their urine increase the levels of plasma testosterone in males (Macrides etal., 1975). Experienced male golden hamsters, on the other hand, do not depend on specific pheromonal odors for this testosterone surge induced by estrous females. Other cues, possibly learned odors from a female, perceived via the main olfactory system, appear to activate the neuroendocrine refiex that results in increased testosterone release (Johnston, 2001). 

Prostatic cancer is androgen-dependent and metastatic disease can be helped by orchidectomy, or by a gonadorelin analogue, e.g. buserelin, goserelin, leuprorelin or triptorelin. These cause a transient stimulation of luteinising hormone and thus testosterone release, before inhibition occurs some patients may experience exacerbation of tumour effects, e.g. bone pain, spinal cord compression. Where this can be anticipated, prior orchidectomy or antiandrogen treatment, e.g. with cyproterone or flutamide, is protective. 

As an endocrine disrupter, 2,4-D causes suppression of thyroid hormone levels, increases thyroid gland mass, and decreases weight of the ovaries and testes [33]. 2,4-D causes slight decreases in testosterone release and significant increases in estrogen release from testicular cells [34]. Male farm sprayers exposed to 2,4-D had lower sperm counts and more spermatic abnormalities compared to men who were not exposed to this chemical [35]. 

In vitro studies have shown that NDGA induces apoptosis in various human and animal cancer cell linesand cell growth of estrogen-positive human breast cancer cells (MCF-7). Among other activities, it also inhibits platelet aggregation, testosterone release, insulin secretion, " human lipoxygenases, and from topical application, skin tumor formation in rodents. ... 

Raya-Rivera, A. M., C. Baez, A. Atala, and J. J. Yoo. 2008. Tissue engineered testicular prostheses with prolonged testosterone release. World J Urol 26 351-358. 

Gonadotropin releasing hormone analogs (goserelin, buserelin, leuprorelin, triptorelin) inhibit gonadotropin release and thus lower testosterone or estrogen levels. They are used to treat breast cancer and prostate cancer. 

LH-RH (Luteinizing Hormone-Releasing Hormone) agonists are drugs that inhibit the secretion of sex hormones. In men, LH-RH agonists cause testosterone levels to fall. In women, LH-RH agonists cause the levels of estrogen and other sex hormones to fall. 

FIGURE 14 In vitro rate of release of testosterone from a PCL capsule (reservoir device), illustrating rate control by drug dissolution when the polymer membrane thickness is small. (From Ref. 68.)... 

Implants are small, sterile cylinders of dmg, inserted beneath the skin or into muscle hssue to provide slow absorption and prolonged achon therapy. This is principally based on the fact that such dmgs, invariably hormones, are almost insoluble in water and yet the implant provides a rate of dissoluhon sufficient for a therapeuhc effect. The British Pharmacopoeia (1993) describes one implant, testosterone. The United States National Formulary (1990) also ineludes oestradiol. Implants are made fiom the pure drug into tablet form by compression or fusion. No other ingredient can be included sinee this may be insoluble or toxie or, most importantly, may influence the rate of drug release. 

McDonnell S Diehl N., Garcia M. and Kenney R. (1989). Gonadotrophin releasing hormone (GnRH) affects precopulatory behavior in testosterone-treated geldings. Physiol Behav 45, 145-149. 

Currently, most strategies for buccal delivery of peptide drugs have focused on the application of excipients that would shorten the time of absorption and adhere drugs to a local site on the mucosa, thus decreasing exposure to proteolytic degradation and possible release of drug back into the mouth cavity. This strategy has been utilized in the buccal delivery of insulin, enkephalin, and testosterone [37, 70]. 

---