L. Gooren - Academia.edu (original) (raw)

Papers by L. Gooren

Handbook of Sexual and Gender Identity Disorders, 2008

... to individual variability, have been systematically reviewed (Schiavi & Rehman, 1995; Sch... more ... to individual variability, have been systematically reviewed (Schiavi & Rehman, 1995; Schiavi, Schreiner-Engel, Mandeli, Schanzer, & Cohen, 1990). ... late onset hypogonadism (LOH) has been recommended by the International Study of the Aging Male (ISSAM), the International ...

European Journal of Endocrinology, 2011

ObjectiveTestosterone has a spectrum of effects on the male organism. This review attempts to det... more ObjectiveTestosterone has a spectrum of effects on the male organism. This review attempts to determine, from published studies, the time-course of the effects induced by testosterone replacement therapy from their first manifestation until maximum effects are attained.DesignLiterature data on testosterone replacement.ResultsEffects on sexual interest appear after 3 weeks plateauing at 6 weeks, with no further increments expected beyond. Changes in erections/ejaculations may require up to 6 months. Effects on quality of life manifest within 3–4 weeks, but maximum benefits take longer. Effects on depressive mood become detectable after 3–6 weeks with a maximum after 18–30 weeks. Effects on erythropoiesis are evident at 3 months, peaking at 9–12 months. Prostate-specific antigen and volume rise, marginally, plateauing at 12 months; further increase should be related to aging rather than therapy. Effects on lipids appear after 4 weeks, maximal after 6–12 months. Insulin sensitivity may...

Nephrology Dialysis Transplantation, 1997

failure but largely to loss of sexual interest, subjectively ascribed to fatigue. The latter was ... more failure but largely to loss of sexual interest, subjectively ascribed to fatigue. The latter was also found in women Background. Sexual dysfunctions are common among patients with chronic renal failure. The prevalence was on haemodialysis or peritoneal dialysis. assessed in a population of 281 patients (20-60 years), Key words: chronic renal failure; prevalence; biochemand it was attempted to determine whether their mode ical variables; psychophysiology; sexual dysfunctions of treatment (haemodialysis, peritoneal dialysis, or kidney transplantation), or biochemical and endocrine variables and neuropathy affect sexual functioning.

The Journal of Men's Health & Gender, 2007

Results: After 60 months the following changes were observed: Erythropoiesis: haemoglobin increas... more Results: After 60 months the following changes were observed: Erythropoiesis: haemoglobin increased from14.44 ± 0.72 to 14.99 ± 0.45 g/dl (p 52% which resolved without intervention. Prostate: PSA increased from 1.77 ± 0.96 to 1.82 ± 0.96 ng/ml (p<0.0001 vs baseline) with a plateau after 24 months. Prostate volume increased from 28.51 ± 11.2 to 30.23 ± 12.4 ml (p<0.0001 vs baseline). 3/255 patients were diagnosed with prostate cancer following elevated PSA (< 4 ng/mL) at 18 weeks of treatment. Tumour grade was T2 in all three and Gleason score 3+3 in two and 3+2 in one patient, resp. They all underwent radical prostatectomy. The proportion was 1.18% with an incidence of 30.334 per 10.000 patient years. For comparison: in the PLCO trial with a 7-year follow-up, the proportion of prostate cancer was 7.35% with an incidence of 116 per 10.000 patient years [1]. – The International Prostate Symptom score (IPSS) improved from 6.73 ± 4.21 to 2.83 ± 1.25 (p<0.0001). Liver enzymes: aspartate transaminase (AST) decreased from 43.05 ± 17.29 to 20.16 ± 3.21 U/L (p<0.0001 vs baseline) reaching a plateau after 24 months, alanine transaminase (ALT) from 43.89 ± 18.11 to 20.54 ± 3.92 U/L (p<0.0001 vs baseline) with a plateau after 36 months.

Neuro Endocrinology Letters, 1984

The Aging Male, 2002

Color profile: Generic CMYK printer profile Composite Default screen Late-onset hypogonadism in m... more Color profile: Generic CMYK printer profile Composite Default screen Late-onset hypogonadism in males Morales and Lunenfeld Color profile: Generic CMYK printer profile Composite Default screen Late-onset hypogonadism in males Morales and Lunenfeld The Aging Male 83 Late-onset hypogonadism in males Morales and Lunenfeld The Aging Male 85

Clinical Chemistry, 2006

Background: Estimation of serum concentrations of free testosterone (FT) and bioavailable testost... more Background: Estimation of serum concentrations of free testosterone (FT) and bioavailable testosterone (bioT) by calculation is an inexpensive and uncomplicated method. We compared results obtained with 5 different algorithms. Methods: We used 5 different published algorithms [described by Sodergard et al. (bioTS and FTS), Vermeulen et al. (bioTV and FTV), Emadi-Konjin et al. (bioTE), Morris et al. (bioTM), and Ly et al. (FTL)] to estimate bioT and FT concentrations in samples obtained from 399 independently living men (ages 40–80 years) participating in a cross-sectional, single-center study. Results: Mean bioT was highest for bioTS (10.4 nmol/L) and lowest for bioTE (3.87 nmol/L). Mean FT was highest for FTS (0.41 nmol/L), followed by FTV (0.35 nmol/L), and FTL (0.29 nmol/L). For bioT concentrations, the Pearson correlation coefficient was highest for the association between bioTS and bioTV (r = 0.98) and lowest between bioTM and bioTE (r = 0.66). FTL was significantly associated ...

Archives of sexual behavior, 1988

This research asked whether androgen substitution therapy is as efficacious in hypogonadotropic h... more This research asked whether androgen substitution therapy is as efficacious in hypogonadotropic hypogonadal men as in hypergonadotropic hypogonadal men. Erotosexual functions of two groups of six men of each diagnostic category were compared after 5-6 years of continuous androgen treatment. Treatment regimen was the same in both groups: Parenteral testosterone esters 250 mg/2 weeks, No difference was found in erectile and ejaculatory potency, but the number of sexual acts and scores of subjective quality of sexual acts, sexual excitement, and frequency of sexual thoughts and of nonsexual parameters as vigor, fatigue, anxiety were more negative in the hypogonadotropic men. The most obvious difference between the two groups is the value of LH/FSH and presumably of LHRH. Hypogonadotropic hypogonadal men may be better treated with gonadotropins (or with pulsatile LHRH, when the hypophysis is intact) than with androgens.

Andrologia, 2013

Male-to-female transsexual persons (MtoF) undergo treatment with antiandrogens and oestrogens fol... more Male-to-female transsexual persons (MtoF) undergo treatment with antiandrogens and oestrogens followed by bilateral orchiectomy. The aim of this study was to investigate the incidence of prostate cancer (PCa) in a cohort of MtoF individuals. Medical records 2306 MtoF treated between 1975 and 2006 of the Amsterdam Gender Clinic were reviewed. Mean age at initiation of treatment was 29.3 ± 12.7 years (range 16-83). Mean follow-up was 21.4 years, resulting in a combined total of 51 173 person-years of exposure and follow-up. Follow-up more than 20 years was available for 303 individuals, including follow-up of more than 30 years in 151 individuals. A single case of PCa was identified in this group. The overall incidence of PCa in this population was 0.04% and 0.13% for individuals who had initiated hormonal treatment after at 40 years or later. PCa in this large MtoF population was rare. However, underdiagnosis is likely due to lack of close prostate monitoring and suppression of PSA due to androgen deprivation. In addition, only a limited number of MtoF individuals have yet reached old age when PCa becomes more common. When diagnosed in this population, there appears to be a tendency for PCa to behave aggressively. Prostate monitoring should be considered in these individuals beginning at age 50 years.

The Netherlands Journal of Medicine

The Journal of Men's Health & Gender, 2007

Given that there is a sex difference in cardiovascular disease, testosterone has long been regard... more Given that there is a sex difference in cardiovascular disease, testosterone has long been regarded as the culprit for this difference. This position is no longer tenable. In epidemiological studies low plasma testosterone levels predict cardiovascular disease and diabetes mellitus, often clustered in the metabolic syndrome. Acute deprivation of testosterone, as in men treated for prostate cancer, leads to impairment of the risk factors for diabetes mellitus and cardiovascular disease. Testosterone administration to hypogonadal men decreases fat mass, increases lean body mass and leads to a reduction in plasma cholesterol, triglycerides and low-density lipoprotein (LDL)-cholesterol levels. Further studies are needed to investigate whether maintaining plasma testosterone levels in the midnormal range improves the risk for cardiovascular disease and diabetes mellitus. ß 2007 WPMH GmbH.

The Journal of Men's Health & Gender, 2006

Elderly men with clinical and laboratory evidence of androgen deficiency are eligible for testost... more Elderly men with clinical and laboratory evidence of androgen deficiency are eligible for testosterone treatment. With proper monitoring this is acceptably safe. In the first year of testosterone treatment there should be a digital rectal examination of the prostate and measurement of prostate specific antigen every three months, thereafter yearly. The rate of increase of prostate specific antigen (PSA) levels is more significant than its absolute values. Levels of haemoglobin and the haematocrit should be monitored. ß 2006 WPMH GmbH.

Objective: To formulate practice guidelines for the endocrine treatment of transsexual persons. P... more Objective: To formulate practice guidelines for the endocrine treatment of transsexual persons. Participants: An Endocrine Society-appointed Task Force of experts, a methodologist, and a medical writer. Evidence: This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence, which was generally low or very low.

The Journal of Steroid Biochemistry and Molecular Biology, 2009

Over the last three decades it has become apparent that testosterone plays a significant role in ... more Over the last three decades it has become apparent that testosterone plays a significant role in the maintenance of bone and muscle mass, in erythropoiesis, and in mental functions. But testosterone is also a key player in glucose homeostasis and lipid metabolism. The metabolic syndrome is a clustering of risk factors predisposing to late onset diabetes mellitus, atherosclerosis and cardiovascular morbidity and mortality. The main components of the syndrome are visceral obesity, glucose intolerance, raised blood pressure and dyslipidaemia (elevated triglycerides, low levels of high-density lipoprotein cholesterol), and a pro-inflammatory and thrombogenic state. Cross-sectional epidemiological studies have reported a direct correlation between plasma testosterone and insulin sensitivity, and low testosterone levels are associated with an increased risk of type 2 diabetes mellitus, dramatically illustrated by androgen deprivation in men with prostate carcinoma. Lower total testosterone and sex hormone-binding globulin (SHBG) predict a higher incidence of the metabolic syndrome. There is now evidence to argue that hypotestosteronaemia should be an element in the definition of the metabolic syndrome. Administration of testosterone to hypogonadal men reverses the unfavorable risk profile for the development of diabetes and atherosclerosis. Testosterone should be regarded as a pivotal hormone for men's health.

Systems Biology in Reproductive Medicine, 2007

Administration of testosterone undecanoate (TU) over 12 months to men with sexual dysfunction and... more Administration of testosterone undecanoate (TU) over 12 months to men with sexual dysfunction and signs of the metabolic syndrome, restored their plasma testosterone (T) levels to the mid-range of reference values. This had a beneficial effect on their sexual functioning as evidenced by an improvement of their scores on the International Index of Erectile Function. The scores on the Aging Male Symptoms score, AMS, were also improved. Most impressive were the improvements in the parameters of the metabolic syndrome; they all improved and appeared largely correlated (i.e., decline in waist circumference with declines of plasma cholesterol and LDL and increase in plasma HDL). Sex hormone binding globulin, SHBG, may be considered as an indicator of the severity of the metabolic syndrome; levels of SHBG initially fell, probably as a result of rising plasma T levels. But over the last six months of the observation period when plasma T rose further, there was a significant increase in plasma SHBG which may be interpreted to indicate an improvement of the metabolic syndrome. Blood pressure improved slightly but significantly. In this cohort of elderly men (54-76 years; median 64 years) there were no safety concerns over a one year period of T administration. Prostate specific antigen, PSA, levels remained stable; the International Prostate Symptoms Score, IPSS, improved slightly. Liver functions and plasma glucose remained stable. Hemoglogin and hematocrit values increased significantly but remained within reference values.

Psychoneuroendocrinology, 1990

Testicular hormones play a decisive role in the sexual differentiation of the genitalia. There is... more Testicular hormones play a decisive role in the sexual differentiation of the genitalia. There is now also an impressive body of knowledge, gathered predominantly from laboratory animals, of the influence of gonadal steroid hormones on the prenatal/perinatal sexual differentiation of the brain. The well-documented mechanisms in animals have been extrapolated, sometimes dogmatically, to the development of sexual orientation and gender identity/role in humans. In principle, it is doubtful that an animal model of human gender identity can be found. Studies in humans have shown that levels of circulating sex steroids and estrogen feedback on luteinizing hormone do not differ between transsexuals and controls. The only reliable sources of information on hormonal influences on human gender identity formation are clinical syndromes in which the hormonal environment of the fetus has been atypical. Follow-up studies of such patients have provided evidence for possible effects of prenatal sex steroids on brain lateralization, sexual orientation and gender role stereotypes. However, a straightforward hormonal effect on gender identity (self-identification as male or female) has been difficult to ascertain up to the present time.

Handbook of Sexual and Gender Identity Disorders, 2008

... to individual variability, have been systematically reviewed (Schiavi & Rehman, 1995; Sch... more ... to individual variability, have been systematically reviewed (Schiavi & Rehman, 1995; Schiavi, Schreiner-Engel, Mandeli, Schanzer, & Cohen, 1990). ... late onset hypogonadism (LOH) has been recommended by the International Study of the Aging Male (ISSAM), the International ...

European Journal of Endocrinology, 2011

ObjectiveTestosterone has a spectrum of effects on the male organism. This review attempts to det... more ObjectiveTestosterone has a spectrum of effects on the male organism. This review attempts to determine, from published studies, the time-course of the effects induced by testosterone replacement therapy from their first manifestation until maximum effects are attained.DesignLiterature data on testosterone replacement.ResultsEffects on sexual interest appear after 3 weeks plateauing at 6 weeks, with no further increments expected beyond. Changes in erections/ejaculations may require up to 6 months. Effects on quality of life manifest within 3–4 weeks, but maximum benefits take longer. Effects on depressive mood become detectable after 3–6 weeks with a maximum after 18–30 weeks. Effects on erythropoiesis are evident at 3 months, peaking at 9–12 months. Prostate-specific antigen and volume rise, marginally, plateauing at 12 months; further increase should be related to aging rather than therapy. Effects on lipids appear after 4 weeks, maximal after 6–12 months. Insulin sensitivity may...

Nephrology Dialysis Transplantation, 1997

failure but largely to loss of sexual interest, subjectively ascribed to fatigue. The latter was ... more failure but largely to loss of sexual interest, subjectively ascribed to fatigue. The latter was also found in women Background. Sexual dysfunctions are common among patients with chronic renal failure. The prevalence was on haemodialysis or peritoneal dialysis. assessed in a population of 281 patients (20-60 years), Key words: chronic renal failure; prevalence; biochemand it was attempted to determine whether their mode ical variables; psychophysiology; sexual dysfunctions of treatment (haemodialysis, peritoneal dialysis, or kidney transplantation), or biochemical and endocrine variables and neuropathy affect sexual functioning.

The Journal of Men's Health & Gender, 2007

Results: After 60 months the following changes were observed: Erythropoiesis: haemoglobin increas... more Results: After 60 months the following changes were observed: Erythropoiesis: haemoglobin increased from14.44 ± 0.72 to 14.99 ± 0.45 g/dl (p 52% which resolved without intervention. Prostate: PSA increased from 1.77 ± 0.96 to 1.82 ± 0.96 ng/ml (p<0.0001 vs baseline) with a plateau after 24 months. Prostate volume increased from 28.51 ± 11.2 to 30.23 ± 12.4 ml (p<0.0001 vs baseline). 3/255 patients were diagnosed with prostate cancer following elevated PSA (< 4 ng/mL) at 18 weeks of treatment. Tumour grade was T2 in all three and Gleason score 3+3 in two and 3+2 in one patient, resp. They all underwent radical prostatectomy. The proportion was 1.18% with an incidence of 30.334 per 10.000 patient years. For comparison: in the PLCO trial with a 7-year follow-up, the proportion of prostate cancer was 7.35% with an incidence of 116 per 10.000 patient years [1]. – The International Prostate Symptom score (IPSS) improved from 6.73 ± 4.21 to 2.83 ± 1.25 (p<0.0001). Liver enzymes: aspartate transaminase (AST) decreased from 43.05 ± 17.29 to 20.16 ± 3.21 U/L (p<0.0001 vs baseline) reaching a plateau after 24 months, alanine transaminase (ALT) from 43.89 ± 18.11 to 20.54 ± 3.92 U/L (p<0.0001 vs baseline) with a plateau after 36 months.

Neuro Endocrinology Letters, 1984

The Aging Male, 2002

Color profile: Generic CMYK printer profile Composite Default screen Late-onset hypogonadism in m... more Color profile: Generic CMYK printer profile Composite Default screen Late-onset hypogonadism in males Morales and Lunenfeld Color profile: Generic CMYK printer profile Composite Default screen Late-onset hypogonadism in males Morales and Lunenfeld The Aging Male 83 Late-onset hypogonadism in males Morales and Lunenfeld The Aging Male 85

Clinical Chemistry, 2006

Background: Estimation of serum concentrations of free testosterone (FT) and bioavailable testost... more Background: Estimation of serum concentrations of free testosterone (FT) and bioavailable testosterone (bioT) by calculation is an inexpensive and uncomplicated method. We compared results obtained with 5 different algorithms. Methods: We used 5 different published algorithms [described by Sodergard et al. (bioTS and FTS), Vermeulen et al. (bioTV and FTV), Emadi-Konjin et al. (bioTE), Morris et al. (bioTM), and Ly et al. (FTL)] to estimate bioT and FT concentrations in samples obtained from 399 independently living men (ages 40–80 years) participating in a cross-sectional, single-center study. Results: Mean bioT was highest for bioTS (10.4 nmol/L) and lowest for bioTE (3.87 nmol/L). Mean FT was highest for FTS (0.41 nmol/L), followed by FTV (0.35 nmol/L), and FTL (0.29 nmol/L). For bioT concentrations, the Pearson correlation coefficient was highest for the association between bioTS and bioTV (r = 0.98) and lowest between bioTM and bioTE (r = 0.66). FTL was significantly associated ...

Archives of sexual behavior, 1988

This research asked whether androgen substitution therapy is as efficacious in hypogonadotropic h... more This research asked whether androgen substitution therapy is as efficacious in hypogonadotropic hypogonadal men as in hypergonadotropic hypogonadal men. Erotosexual functions of two groups of six men of each diagnostic category were compared after 5-6 years of continuous androgen treatment. Treatment regimen was the same in both groups: Parenteral testosterone esters 250 mg/2 weeks, No difference was found in erectile and ejaculatory potency, but the number of sexual acts and scores of subjective quality of sexual acts, sexual excitement, and frequency of sexual thoughts and of nonsexual parameters as vigor, fatigue, anxiety were more negative in the hypogonadotropic men. The most obvious difference between the two groups is the value of LH/FSH and presumably of LHRH. Hypogonadotropic hypogonadal men may be better treated with gonadotropins (or with pulsatile LHRH, when the hypophysis is intact) than with androgens.

Andrologia, 2013

Male-to-female transsexual persons (MtoF) undergo treatment with antiandrogens and oestrogens fol... more Male-to-female transsexual persons (MtoF) undergo treatment with antiandrogens and oestrogens followed by bilateral orchiectomy. The aim of this study was to investigate the incidence of prostate cancer (PCa) in a cohort of MtoF individuals. Medical records 2306 MtoF treated between 1975 and 2006 of the Amsterdam Gender Clinic were reviewed. Mean age at initiation of treatment was 29.3 ± 12.7 years (range 16-83). Mean follow-up was 21.4 years, resulting in a combined total of 51 173 person-years of exposure and follow-up. Follow-up more than 20 years was available for 303 individuals, including follow-up of more than 30 years in 151 individuals. A single case of PCa was identified in this group. The overall incidence of PCa in this population was 0.04% and 0.13% for individuals who had initiated hormonal treatment after at 40 years or later. PCa in this large MtoF population was rare. However, underdiagnosis is likely due to lack of close prostate monitoring and suppression of PSA due to androgen deprivation. In addition, only a limited number of MtoF individuals have yet reached old age when PCa becomes more common. When diagnosed in this population, there appears to be a tendency for PCa to behave aggressively. Prostate monitoring should be considered in these individuals beginning at age 50 years.

The Netherlands Journal of Medicine

The Journal of Men's Health & Gender, 2007

Given that there is a sex difference in cardiovascular disease, testosterone has long been regard... more Given that there is a sex difference in cardiovascular disease, testosterone has long been regarded as the culprit for this difference. This position is no longer tenable. In epidemiological studies low plasma testosterone levels predict cardiovascular disease and diabetes mellitus, often clustered in the metabolic syndrome. Acute deprivation of testosterone, as in men treated for prostate cancer, leads to impairment of the risk factors for diabetes mellitus and cardiovascular disease. Testosterone administration to hypogonadal men decreases fat mass, increases lean body mass and leads to a reduction in plasma cholesterol, triglycerides and low-density lipoprotein (LDL)-cholesterol levels. Further studies are needed to investigate whether maintaining plasma testosterone levels in the midnormal range improves the risk for cardiovascular disease and diabetes mellitus. ß 2007 WPMH GmbH.

The Journal of Men's Health & Gender, 2006

Elderly men with clinical and laboratory evidence of androgen deficiency are eligible for testost... more Elderly men with clinical and laboratory evidence of androgen deficiency are eligible for testosterone treatment. With proper monitoring this is acceptably safe. In the first year of testosterone treatment there should be a digital rectal examination of the prostate and measurement of prostate specific antigen every three months, thereafter yearly. The rate of increase of prostate specific antigen (PSA) levels is more significant than its absolute values. Levels of haemoglobin and the haematocrit should be monitored. ß 2006 WPMH GmbH.

Objective: To formulate practice guidelines for the endocrine treatment of transsexual persons. P... more Objective: To formulate practice guidelines for the endocrine treatment of transsexual persons. Participants: An Endocrine Society-appointed Task Force of experts, a methodologist, and a medical writer. Evidence: This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence, which was generally low or very low.

The Journal of Steroid Biochemistry and Molecular Biology, 2009

Over the last three decades it has become apparent that testosterone plays a significant role in ... more Over the last three decades it has become apparent that testosterone plays a significant role in the maintenance of bone and muscle mass, in erythropoiesis, and in mental functions. But testosterone is also a key player in glucose homeostasis and lipid metabolism. The metabolic syndrome is a clustering of risk factors predisposing to late onset diabetes mellitus, atherosclerosis and cardiovascular morbidity and mortality. The main components of the syndrome are visceral obesity, glucose intolerance, raised blood pressure and dyslipidaemia (elevated triglycerides, low levels of high-density lipoprotein cholesterol), and a pro-inflammatory and thrombogenic state. Cross-sectional epidemiological studies have reported a direct correlation between plasma testosterone and insulin sensitivity, and low testosterone levels are associated with an increased risk of type 2 diabetes mellitus, dramatically illustrated by androgen deprivation in men with prostate carcinoma. Lower total testosterone and sex hormone-binding globulin (SHBG) predict a higher incidence of the metabolic syndrome. There is now evidence to argue that hypotestosteronaemia should be an element in the definition of the metabolic syndrome. Administration of testosterone to hypogonadal men reverses the unfavorable risk profile for the development of diabetes and atherosclerosis. Testosterone should be regarded as a pivotal hormone for men's health.

Systems Biology in Reproductive Medicine, 2007

Administration of testosterone undecanoate (TU) over 12 months to men with sexual dysfunction and... more Administration of testosterone undecanoate (TU) over 12 months to men with sexual dysfunction and signs of the metabolic syndrome, restored their plasma testosterone (T) levels to the mid-range of reference values. This had a beneficial effect on their sexual functioning as evidenced by an improvement of their scores on the International Index of Erectile Function. The scores on the Aging Male Symptoms score, AMS, were also improved. Most impressive were the improvements in the parameters of the metabolic syndrome; they all improved and appeared largely correlated (i.e., decline in waist circumference with declines of plasma cholesterol and LDL and increase in plasma HDL). Sex hormone binding globulin, SHBG, may be considered as an indicator of the severity of the metabolic syndrome; levels of SHBG initially fell, probably as a result of rising plasma T levels. But over the last six months of the observation period when plasma T rose further, there was a significant increase in plasma SHBG which may be interpreted to indicate an improvement of the metabolic syndrome. Blood pressure improved slightly but significantly. In this cohort of elderly men (54-76 years; median 64 years) there were no safety concerns over a one year period of T administration. Prostate specific antigen, PSA, levels remained stable; the International Prostate Symptoms Score, IPSS, improved slightly. Liver functions and plasma glucose remained stable. Hemoglogin and hematocrit values increased significantly but remained within reference values.

Psychoneuroendocrinology, 1990

Testicular hormones play a decisive role in the sexual differentiation of the genitalia. There is... more Testicular hormones play a decisive role in the sexual differentiation of the genitalia. There is now also an impressive body of knowledge, gathered predominantly from laboratory animals, of the influence of gonadal steroid hormones on the prenatal/perinatal sexual differentiation of the brain. The well-documented mechanisms in animals have been extrapolated, sometimes dogmatically, to the development of sexual orientation and gender identity/role in humans. In principle, it is doubtful that an animal model of human gender identity can be found. Studies in humans have shown that levels of circulating sex steroids and estrogen feedback on luteinizing hormone do not differ between transsexuals and controls. The only reliable sources of information on hormonal influences on human gender identity formation are clinical syndromes in which the hormonal environment of the fetus has been atypical. Follow-up studies of such patients have provided evidence for possible effects of prenatal sex steroids on brain lateralization, sexual orientation and gender role stereotypes. However, a straightforward hormonal effect on gender identity (self-identification as male or female) has been difficult to ascertain up to the present time.