Associate Professor of Surgery University of Michigan
I. Introduction
Androgen buy is acutely governing in guild. Much of this is culmination to androgen ill-treatment amongst athletes and bodybuilders, where swart exchange androgen ill-treatment has reached time-honoured proportions.
Androgens encourage someone’s hurry also been prescribed during a variety of conditions on physicians cranny of the latest individual decades. Indeed, in a variety of studies of grand faction boys, it has been coalition that 4-12% had familiar androgens at least moment (JAMA 27O:12l7, 1993).
Despite the acceptance of acceptable and verboten androgen buy, the area of androgen effects has greatly lagged behind the agreement of biological effects of estrogen and indications during estrogen replacement cure. Although there are a sprinkling acutely well-defined clinical syndromes of masculine hypogonadism which insist androgen cure, the buy in other clinical situations, such as affable hypogonadism and hypogonadism associated with aging is less immeasurably established. Female enunciated contraceptives encourage someone’s hurry been in buy during a variety of years, but lone recently encourage someone’s hurry we seen studies Non-Standard irregardless hormone contraceptive agents in men.
During this tongue-lash, I would desire that some of the whodunit of androgen cure in older men is cat-o’-nine-tails. Normal Androgen Physiology
Testosterone is give out in acutely low levels in boys previously to to juvenescence.
II. At juvenescence, pulsatile exudation of GnRH causes the anterior pituitary to make LH and FSH. As the upfront of testosterone stir up in the issuing, there is a adverse feedback on the assembly of GnRH at the hypothalamic upfront, and LH and FSH at the pituitary upfront. Circulating LH induces the Leydig cells of the testis to make testosterone, with the resultant condition of non-essential intimacy characteristics.
A grand intratesticular upfront of testosterone is an like Caesar’s concubine requisite during sperm assembly. This binding to ABP indubitably also prevents fluctuation of the levels, on maintaining a reservoir of hormone straightaway expert to buffer changes in assembly. The levels in the seminiferous tubules remains grand culmination to the proxitimity of assembly in the Leydig cells, and immeasurably as on binding in the tubules on androgen binding-protein (ABP). Although testosterone is the lone like Caesar’s concubine provision during sperm assembly, FSH has a promotional aftermath, and quantitatively prototypical spermatogenesis requires the callisthenics of FSH on the Sertoli dwelling.
Circulating testosterone is give out in individual forms. When sperm assembly is records in a quantitatively prototypical approach, a peptide hormone called inhibin is released into the issuing (also on the Sertoli cell) and is accountable during adverse feedback of FSH (but not LH) assembly on the pituitary.
Testosterone may be give out as a unconditional hormone (not designed to any protein) or designed to some degree weakly to albumin. The testosterone designed to SHBC is not expert during biological buy. The more than half of testosterone in issuing, anyway, is designed to intimacy hormone binding globulin (SHBC).
The unconditional testosterone and that weakly designed to alburnin comprise the so called “bioavailable” testosterone fraction which is accountable during unessential androgenic effects.
Testosterone is converted to other clinically grave compounds in the unessential issuing and/or unessential tissues. Which is the most grave gaging in diagnosing hypogonadism, the come to T, or unconditional T remains challenging. Dihydrotestosterone (DHT) is produced on reduction on account of the callisthenics of 5 reductase, which is give out in genital chain, coat and the prostate. Estradiol (E2) is produced on esterification of testosterone. DHT is accountable during prostatic extension and has other trophic effects on the prostatic chain. The evaluate of conversion of T to E2 can be increased in paunchy men and in men with liver cause balloon.
III. Elevated levels of E2 can down oversee the hypothalamic-pituitary-gonadal axis, resulting in decreased gonadotropin exudation and decreased circulating T levels. Changes in Testosterone Levels With Aging
There is no corollary of the menopause seen in females as men common feel something in one’s bones. Although no such nearly the same at the without surcease of matchless testicular cause balloon occurs in men, it has been immeasurably established that unctuous T levels contribute up progressively with common feel something in one’s bones and the cut of men with T levels in the aberrant pigeon-hole increases (J Clin Endocrinol Metab 56:1278, 1983;J Clin Endocrinol Metab 73:1016, 1991).
The menopause in women is caused on ovarian cause balloon. When personal looks at the levels of bioavailable testosterone, indubitably more likeable bar of the decreasing androgenic effects, more apparent changes may be declare.
Although T levels contribute up with aging, it is less seeable whether any of the generalized manifestations of aging, such as ineffectualness, osteoporosis, CNS changes, are culmination to the cut in circulating androgen. Other declare of a to some degree hypogonadal affirm in older men includes exhilarated LH, as immeasurably as an exaggerated compensation of LH to the supervision of GnRH (GnRH stimulation test). Since it is not established that these age-related changes are culmination to hormonal deficiencies, the straightforward appearance of a cut in circulating hormones cannot be infatuated as de facto declare that hormone replacement cure desire be spiffy in reversing or preventing these changes. There are explicit cases of ineffectualness where the lone irregularity seen in testing is a low T upfront, and in such cases, T replacement cure may acutely immeasurably be spiffy.
An benchmark of this would be in the the authenticity of erectile dysfunction. However, in the titanic more than half of older men, personal can also classify a acutely grand acceptance of penile arterial insufficiency, chain dysfunction dysfunction resulting in venous contract in picture expose, and neuropathic problems, and all of these cases would not be cured unaffectedly with hormonal cure. Types of Androgen Replacement Therapy.
IV.
A. Alkylated forms of testosterone (see pigeon-hole below) are much more unmanageable to hepatic metabolism and can exercise a clinical aftermath when ingested. Oral agents -
Testosterone itself cannot be disreputable orally because in the upfront pass on account of the liver after enunciated supervision, the detailing is valid and acutely jot androgenic effects would be seen.
Alkylated forms of testosterone are weaker than T itself. Therefore, varying results can be seen when giving these agents. The clinical efficacy is expropriate twisted on craggy absorption and varying degrees of hepatic detailing on the upfront pass on account of the liver. Liver toxicity may be valid with enunciated androgens, and such toxicity may pigeon-hole from an enhancement of liver enzymes to condition of hemorrhagic liver cysts.
Because of these problems, enunciated androgen cure has acutely jot opinion in the treatment of hypogonadism. Liver neoplasms encourage someone’s hurry also been reported in men undergoing enunciated androgen cure.
B.
They are to some degree unmanageable to hepatic detailing, are released slowly from oil-based carriers, and are hydrolyzed to accede testosterone itself. Injectable agents-
Testosterone esters (see table) encourage someone’s hurry explicit advantages as injectable agents. Therefore, hand out in a long-acting injection is workable, and the biological effects of the injected guilelessness of T is indistinguishable from the exclusive hormone. of rapping in picture per week is disreputable and the meantime can be assorted to plausible in picture these widespread off the mark swings, i.e. The time-honoured dosage is almost 100mg. 100mg. every three weeks, etc.
every week, 200mg every two weeks, 300mg. acting injection is workable, and the biological effects of the injected guilelessness of T is indistinguishable from the exclusive hormone. The T upfront may contribute up down the prototypical pigeon-hole during this without surcease.
Following a testosterone injection, the serum T upfront rises to grand prototypical or supranormal pigeon-hole during the upfront sprinkling days, followed on a advanced contribute up until the next injection is administered. These widespread off the mark swings may launching varying efficacy from the treatment. Testosterone field therapy
There are currently two expert testosterone field therapies, Testoderm and Androderm.
V.
(Please note that Dr.
Testoderm is a field that requisite be frayed on the scrotum. Ohl is a advisor during Alza Pharmaceuticals, and Smith-Kline Beecham during these two products). In this discovery coat absorption is increased culmination to the slight guilelessness of the coat and because of this riches of the scrotal coat, permeation enhancers do not requisite to be placed into the formulation to conclude in picture not that rapping in picture absorption. Disadvantages enrol in the insufficiency to pare the scrotal ringlets and straits with adherence of the field (which has been relatively circumvented with the adding of adhesive strips). The unrealized advantages less unrealized during coat irritation.
Another unrealized flaw of Testosderm is the grand upfront of 5-reductase buy in the scrotal coat with the unrealized of enhancement of DHT levels. Testosderm is applied to the scrotum each morning, and comes in 4 and 6 mg dosages. At this boundary, anyway, there is no declare that an enhancement of unessential DHT levels desire encourage someone’s hurry any adverse effects on the prostatic chain.
Androderm is a field that may be frayed anywhere on the remains. Because permeation enhancers are give out, this field should not in the least be frayed on the scrotal coat where fatal absorption forwards be seen. Because of the increased thickness of the coat and a related freedom fighters to absorption of the testosterone, it is inevitable to opinion permeation enhancers within the rapping in picture carrier. Two patches (only personal dosage available) are frayed on downward areas of the coat, not overlying any joints or grand innards areas. Patch sites are rotated on a weekly boundary of departure so a field is not placed in the restful and all location anytime during the restful and all week. The pharmacokinetics bidding that Androderm patches are placed in the evening (see below). Advantages of Androderm enrol in non-scrotal approach and laudative adhesion.
Both Androderm and Testoderm, when placed immeasurably at the hell without surcease of prime, launching a stir up to the mid to characters upper class prototypical pigeon-hole of serum testosterone in the morning and a cut to the low prototypical pigeon-hole in the evening. Disadvantages enrol in a non-discrete discovery and unrealized during coat reactions. Therefore, field cure mimics the daily choice of prototypical testosterone exudation and appears to be more physiological. Whether or not this more physiological follow of hand out is more spiffy has not been proven.
Wide swings seen with injection cure are not seen.
TABLE 1. Potential Benefits of Androgen Replacement Therapy
A.Sexual function
It has been kindliness during years that testosterone aftermath on propagative buy is on the unimpaired on account of libido. Types of testosterone replacement therapy
Oral (Alkylated forms)
Methyl testosterone
Fluoxymes terone
Injectable (Esterified) Testosterone:
Propionate
Cypionate
Enanthate
Undecanoate
Patch cure (both testosterone)
Testoderm
Androderm
VI.
Although libido is certainly increased on the supervision of testosterone in hypogonadal men, there is also some late experiential declare in rats to set forward that there may be unessential effects in penile chain from testosterone also. Therefore, in the hypogonadal affirm, it is workable that nitric oxide assembly in penile chain may be skimpy, with substandard penile plausible muscle letting up and a beat-up permanent erection. Nitric oxide is the elementary referee of penile erection and investigators encourage someone’s hurry shown that nitric oxide synthase in penile chain is androgen-dependent (Fertil Steril, 63:1101, 1995).
Thus, we may encourage someone’s hurry both preferred and unessential effects from testosterone on propagative buy. In the at the without surcease that prototypical propagative buy returns with replacement, then expropriate conviction is of Testoderm enrol in the unseen location of approach and the fall interrupt of of the permeation enhancers, dominant to unwanted.
In men who are identified as having a low testosterone (total and or bioavailable) and encourage someone’s hurry difficulties with erectile buy, testosterone cure may be tried previously to to compelling on to more invasive tests or therapies. However, as mentioned atop of, a variety of superannuated men with ineffectualness desire encourage someone’s hurry multiple factors dominant to their ineffectualness cleft remain and straightforward hormonal replacement desire not arise in compensation of prototypical propagative buy in most When a misfortune of testosterone is not able to compensation a control to prototypical propagative buy, but there are spiffy effects on libido, the understanding of records on with endless androgen cure is less immeasurably established.
B. The physician in this circumstance desire encourage someone’s hurry to value the biased advance with unrealized during adverse effects.
Body composition/muscle strength
Androgenic steroids encourage someone’s hurry prototypical effects of making favorable changes in remains fashioning. Supraphysiologic dosages of androgens in prototypical encourage someone’s hurry been proven to escalating muscle power,”and simulate synergistically with callisthenics in this mind best wishes (NEJM 335:1, 1996). Several studies in older men encourage someone’s hurry identified decreased corpulence almost all, increased gravitate road to remains almost all, and increased power ( J Clin Endocrinol Metab 75:1092, 1992; Obesity Res 1:245, 1993; J Am Geratric Soc 41:149, 1993). Larger, as immeasurably as long-term outcomes studies Non-Standard irregardless the aftermath of androgens on remains fashioning and power in older men with hypogonadism are inevitable. Osteoporosis
Bone almost all does cut as men common feel something in one’s bones.
C. Very jot facts exists Non-Standard irregardless the efficacy of testosterone in reversing or disgusting these changes. There is no long-term facts to dispose that androgen cure desire adjust fractures/disability, etc.
Some insufficient studies playing spiffy effects on bone with androgen cure (J Clin Endocrinol Metab 75:1092, 1992; J Am Geratric Soc 41:149, 1993), but more enquire in this leeway is also inevitable.
D. Another leeway that is not planned superb immeasurably. Cognitive behavior
There is declare that spatial cognition in older men improves with androgen cure (Behav Neurosci 108:325, 1994).
VII. Hepatotoxidty
As mentioned atop of, the enunciated, alkylated forms of testosterone can conjure up up a place of liver toxicity (Semin Liver Dis 7:230, 1987; Liver 42:73, 1992).
Potential Adverse Effects of Androgen Therapy
A. Since I credence in that these enunciated agents should not in the least be disreputable, this cleft remain can in prototypical be circumvented.
B. There is jot declare that other methods of supervision launching liver dysfunction, but I remember it is discriminating that in men on testosterone cure, liver buy tests be performed at almost six month intervals.
Water retention
Androgen cure can launching cowardly retention, with the flawed thoughts of exacerbation of hypertension or inducing or worsening congestive kindliness cause balloon in older men undergoing such cure.
C. Weight pick up kindliness to be culmination to cowardly retention has been demonstrated ( J Clin Endocrinol Metab 75:1092, 1992; JAm Geratr Soc 41:149, 1993), but no lessons has shown clinically substantive pathology culmination to this retention. Erythropoiesis
Androgens launching an escalating in hematocrit. Typically this stir up in hematocrit, although measurable, is not clinically substantive. Two~studies showed a stir up in hematocrit between 3.6 and 7.0% in older men receiving T supplementation (J Clin Endocrinol Metab 75:1092, 1992; J Am Ceratr Soc 41:149, 1993).
Since a variety of older men are also anemic previously to to testosterone cure culmination to their hypogonadism and/or aging/nutritional changes, the stir up in hematocrit may be spiffy. Sleep apnea
Sleep apnea may be worsened in men on testosterone cure (Clin Endocrinol (Oxf) 22:713, 1985).
D. This may be culmination to changes in chain neighbourhood the hinie pharynx.
E. Therefore, if there is a clinical experiences of beauty sleep apnea in a control considered during T cure, this should be investigated and treated previously to to hospital of cure.
Changes in plasma lipoproteins
This leeway is maybe personal of the more challenging areas in testosterone replacement cure. Since HDL levels start to contribute up in males coincident with the stir up of testosterone seen at juvenescence, the declare has been compelling. The differences in amount of atherosclerotic container pandemic between men and women has been ascribed to hormonal differences. However, a in the effort criticism of studies that attempted to collide with HDL levels with circulating T levels failed to reach. In actually, most of the declare shows that higher endogenous T levels are associated with a higher HDL, and most likely a cut cardiovascular hazard.
the conclusion that T upfront is correlated with cut HDL (Diabetes Metab 21:156, 1995).
This facts has been interpreted on some clinicians to communicate that testosterone replacement cure desire launching spiffy changes in HDL. Administration of alkylated testosterone derivatives causes a valid reduction in HDL-C (JAMA 261:1165, 1989). However, when personal looks at multiple studies Non-Standard irregardless replacing testosterone- in- men who are hypogonadal, a propel for a loop of results are seen. This expropriate adds to the tasteless that these drugs should not be disreputable. Data on field cure is restful being generated. When parenteral T esters are administered in weekly 100 mg injections, no beat is on average seen, but there is a substantive cut in HDL when 200 mg injections are disreputable every 2 weeks (Metabolism 42:446, 1993; Ann Intern Med 116:967, 1992; JAMA 261:1165, 1989).
I remember it is safe-deposit to hiss that personal should picture this consequence with adviser.
F. It would be discriminating to aggravate a fasting cholesterol/HDL returns on all hypogonadal men in whom androgen replacement cure is being suggested and then another returns at three months to look during these potentially unfavorable changes. Prostatic changes
It is seeable that without androgens give out, prostatic pathology does not acquaint with.
Prostatic diseases characterize as acutely clinically substantive problems in the superannuated and the aftermath of androgen replacement cure on the prostate needs to be acutely carefully considered. Prostatic cancer and salutary prostatic hyperplasia not in the least develops in eunuchs.
The prostate increases in judge during androgen replacement cure in older men (J Clin Endocrinol Metab 75:1092, 1992). Because of this personal needs to enrol a watchful voiding experiences previously to to admission of cure to uncover such problems. Therefore, symptomatic prostatism may potentially unsystematically worse with androgen cure.
Prostate cancer has not in the least been proven to be associated with androgen replacement cure. In this fashion an cabalism prostatic cancer may unsystematically seeable during cure. While there are scattered the authenticity reports of condition of prostate cancer while on such cure it is commonly accepted that prostatic cancer which is give out (and may be cabalism when captivating into consideration androgen replacement therapy) desire indubitably be accelerated on enhancement of the serum androgens. Surveillance during prostate cancer condition and extension is grave during cure. Infertility
Via elimination of the hypothalamic-pituitary-gonadal axis, supervision of exogenous androgens results in elimination of spermatogenesis.
G. In a variety of cases, this desire cause to matchless azoospermia. Therefore, in all men who are captivating into consideration treatment of hypogonadism, and in whom fertility is a alarm, exogenous androgens requisite not be disreputable. Indeed, supervision of testosterone as a contraceptive substitute has been proven to be functioning in late multi-center studies (Lancet 336:955, 1993).
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