Pharmacokinetics and pharmacodynamics of subcutaneous testosterone implants in hypogonadal men

Jockenhövel, F.; Vogel, E.; Kreutzer, Michel; Relnhardt, W.; Lederbogen, S; Reinwein, D.

doi:10.1111/j.1365-2265.1996.tb02061.x

Cited by 75 publications

(48 citation statements)

References 38 publications

(58 reference statements)

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“…75,76 The standard dosage is four 200 mg pellets (800 mg) implanted subdermally at intervals of 5 to 7 months. 77 Yet the in vivo testosterone release rate of these testosterone pellets and its determinants have not been studied systematically.…”

Section: Subdermal Implantsmentioning

confidence: 99%

The benefits and risks of testosterone replacement therapy: a review

Bassil¹,

Alkaade²,

Morley

2009

TCRM

140

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Section: Subdermal Implantsmentioning

confidence: 99%

The benefits and risks of testosterone replacement therapy: a review

Bassil¹,

Alkaade²,

Morley

2009

TCRM

140

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“…Male mice with targeted disruption of the nNOS gene (nNOS Ϫ ) display a great increase in aggressive behavior and excessive and inappropriate mounting behavior (11). Because androgens also promote aggressive behavior (23,24), facilitate mounting behavior (25,26), and decrease gonadotropin release (27,28), we wanted to elucidate whether the androgens, testosterone (T) and its 5␣ reduced metabolite, dihydrotestosterone (DHT), modulate nNOS activity in the brain and the potential mechanism(s) by which this may occur.…”

mentioning

confidence: 99%

Castration increases and androgens decrease nitric oxide synthase activity in the brain: Physiologic implications

Singh¹

2000

Proceedings of the National Academy of Sciences

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Sex differences in nitric oxide synthase (NOS) activity in different regions of the rat brain and effects of testosterone and dihydrotestosterone (DHT) treatment in orchidectomized animals were investigated. Regional but no sex differences in NOS activity were detected in gonadectomized animals. Orchidectomy significantly increased NOS activity in the hypothalamus, ''amygdala,'' and cerebellum but not in the cortex. In the hypothalamus, the increase in NOS activity after castration and its reversal by androgen treatment was mimicked by changes in neuronal NOS mRNA level. In contrast, androgen receptor (AR) mRNA level in the hypothalamus was slightly reduced by castration and increased by treatment with DHT. Again in the hypothalamus, the increase in NOS activity in castrated rats was accompanied by an increase in the number of neuronal NOS؉ cells determined immunohistochemically, whereas androgen treatment prevented this increase. The changes in NOS؉ neurons correlated with the changes in the number of AR؉ cells to a degree. Overlap of AR in NOS؉ cells was not present in the regions of the hypothalamus analyzed. These results indicate that testosterone or, most likely, its metabolite DHT down-regulates NOS activity, mRNA expression or stabilization, and the number of neuronal NOS؉ neurons. N itric oxide (NO) synthesized by the enzyme neuronal nitric oxide synthase (nNOS) plays an important role in many brain functions. These include effects on long-term potentiation (1), gonadotropin secretion (2-10), and sexual behavior (11)(12)(13). NO functions as a neurotransmitter (2-10) and nNOS is present near gonadotropin-releasing hormone terminals (14) and in regions of the brain that appear to regulate emotional behaviors (15, 16). Estradiol (E 2 ) up-regulates endothelial NOS in endothelial cells (17,18) and nNOS in the brain (18-21), and many of the actions of E 2 on the brain have been suggested to be through a NO-mediated mechanism (2-10, 18-22). Administration of E 2 and progesterone to ovariectomized rats leads to an increase in the luteinizing hormone surge, the magnitude of which is significantly attenuated after administration of nNOS antisense oligonucleotides into the third ventricle (22), suggesting an intermediary role of NO in modulating some actions of E 2 by up-regulating nNOS activity.However, the actions of androgens on NOS activity in the brain are not clear. Male mice with targeted disruption of the nNOS gene (nNOS Ϫ ) display a great increase in aggressive behavior and excessive and inappropriate mounting behavior (11). Because androgens also promote aggressive behavior (23, 24), facilitate mounting behavior (25, 26), and decrease gonadotropin release (27, 28), we wanted to elucidate whether the androgens, testosterone (T) and its 5␣ reduced metabolite, dihydrotestosterone (DHT), modulate nNOS activity in the brain and the potential mechanism(s) by which this may occur.Therefore, sex-related and region-specific distributions of NOS in select regions of the rat brain of both sexes were assessed as ...

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“…The possibility of extrusion, although rare, also exists (40). A review of 13 years of experience in subdermal testosterone implantation in 221 men showed limited adverse local effects (11% of total 973 consecutive implants) such as extrusion, bleeding, and inflammations/infections.…”

Section: Subcutaneous Implantsmentioning

confidence: 96%

Testosterone Hormone Replacement Therapy: State-of-the-Art and Emerging Technologies

et al. 2006

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In the human male, testosterone is the major circulating androgen. The clinical effects of androgen are numerous, and testosterone deficiency is associated with a number of clinical abnormalities. At present, a variety of preparations containing testosterone is available for the treatment of androgen deficiency. Ideally, those treatments have to produce and maintain physiologic serum concentrations of the hormone. This article reviews the current existing testosterone dosage forms on the market with their advantages and drawbacks and examines new and emerging technology developments concerning this therapy. In particular, the latest innovations in transdermal delivery are explored.

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Pharmacokinetics and pharmacodynamics of subcutaneous testosterone implants in hypogonadal men

Abstract: T-pellets are the androgen formulation with the longest biological action and strongest pharmacodynamic efficacy in terms of gonadotrophin suppression. The pharmacokinetic features are advantageous compared to other T preparations and the patient acceptance is high.

Cited by 75 publications

References 38 publications

The benefits and risks of testosterone replacement therapy: a review

The benefits and risks of testosterone replacement therapy: a review

Castration increases and androgens decrease nitric oxide synthase activity in the brain: Physiologic implications

Testosterone Hormone Replacement Therapy: State-of-the-Art and Emerging Technologies

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