Follow‐up of Prolactin Levels in Long‐term Oestrogen‐treated Male‐to‐female Transsexuals With Regard to Prolactinoma Induction

Abstract

As in laboratory animals, long-term oestrogen treatment in the human male might induce prolactinomas. We here report on PRL levels in 142 male-to-female transsexuals, treated with 100 mg cyproterone acetate and 100 micrograms ethinyloestradiol per day for 6-108 months (median 52). PRL levels varied markedly between individuals. No relation with age and length of treatment period was found. In 42 subjects in whom PRL levels were followed serially, a slight fall was measured after 12-15 months of treatment. Galactorrhoea, present in 10 of 142 subjects, was unrelated to PRL levels. In 34 subjects in whom PRL levels were measured during treatment and 3 weeks after withdrawal, PRL levels fell significantly. Dopamine in doses of 0.1 microgram/kg/min and 1.0 microgram/kg/min was administered to six subjects with PRL levels greater than 1000 mU/l and six subjects with PRL levels less than 500 mU/l. No difference in the percentage decrease of PRL levels was found between these two groups. However, administration of monoiodotyrosine, an inhibitor of central dopamine synthesis, to these two groups, induced a significantly smaller release of PRL (expressed as percentage change) in subjects with PRL greater than 1000 mU/l than in those with PRL less than 500 mU/1 possibly indicating a loss of control of central dopaminergic regulation. These findings suggest that the risk of inducing prolactinomas through cross-gender hormone treatment is likely to be small.

Cyproterone acetate vs leuprolide acetate in combination with transdermal oestradiol in transwomen: a comparison of safety and effectiveness

“…PRL levels were significantly increased after 12 months in the CPA+E group only. Our findings are supported by other studies which showed an increase in PRL levels during administration of CPA combined with oestrogens or CPA alone . At least eight cases of prolactinoma have been reported in the literature after CHT in transwomen.…”

Effect of estrogens on prolactin secretion in transsexual subjects

“…, 1985, 1988). Concern has been raised that male transsexuals treated with high doses of estrogen may have greater risk of hyperprolactinemia and possibly the induction of prolactinoma (Shy et al, 1983;Gooren et al, 1985Gooren et al, , 1988. Also there is increasing concern that the recent apparent increase of hyperprolactinemia in women may be causally related to increased use of estrogens (Sherman et al, 1978;Teperman et al, 1980).…”

Pharmacotherapy Considerations in the Management of Transgender Patients: A Brief Review

“…However, it is not recommended to monitor D‐dimer levels during estrogen treatment . Up to 20% of male‐to‐female transsexuals have elevations in prolactin levels with associated enlargement of the pituitary gland; levels typically return to normal with dose reduction or discontinuation of therapy . Cardiovascular concerns are a point of uncertainty in estrogen therapy.…”