Bromocriptine, a Dopamine Agonist, Increases Growth Hormone Secretion in a Patient with Acromegaly

Abstract

Bromocriptine, a potent D2-dopamine agonist, suppresses growth hormone (GH) secretion in most patients with acromegaly and has been approved for the treatment of acromegaly. Here we report a patient with acromegaly who showed increased GH secretion after administration of bromocriptine. A 70-year-old man with acromegalic manifestation was admitted to our hospital because of a pituitary tumor invading to the right cavernous sinus detected by brain magnetic resonance imaging. Serum GH and insulin-like growth factor-I (IGF-I) levels were elevated in several occasions (GH: 15.0-51.7 ng/mL, reference range: < 2.47 ng/mL; and IGF-I: 776-856 ng/mL, reference range: 57-175 ng/mL). Effect of bromocriptine on serum GH levels was then studied because pre-operative treatment with a D2-dopamine agonist was planned in order to reduce the tumor size and serum GH levels before surgery. After oral administration of 2.5 mg of bromocriptine, serum GH levels were unexpectedly increased from 30.7 ng/mL to 189 ng/mL, despite the fact that the levels of prolactin (PRL) were decreased from 4.2 ng/mL to 0.6 ng/mL. By contrast, serum GH levels were decreased by a somatostatin analogue, octreotide. Transsphenoidal surgery of the pituitary tumor was performed after treatment of octreotide. Histological analysis and immunohistochemistry revealed a GH-producing pituitary adenoma positive for D2-dopamine receptor. This case of acromegaly suggests that the preliminary test with a single administration of a short-acting D2-dopamine agonist, bromocriptine, is mandatory before the long-term therapy with a D2-dopamine agonist in patients with GH-secreting pituitary tumors.

Prolactin and Growth Hormone Signaling and Interlink Focused on the Mammosomatotroph Paradigm: A Comprehensive Review of the Literature

“…In the study by Akirov et al [100], the mean IGF1 increase while undergoing cabergoline treatment was 1.7 ± 0.4 × the upper limit of normal. Other previous studies described similar results, reporting an increase of serum GH/IGF1 levels with DA [102,103].…”

The Protective Effects of Acetyl L-Carnitine for The Offspring and Lactating Moms of Rats Received Bromocriptine

“…Such as the descent of the testes in young rats, but bromocriptine and carnitine together were given to nursing mothers, which led to a shorter period of time in some factors compared to treatment with bromocriptine alone, and bromocriptine significantly reduced the level of the prolactin hormone, or, in other words, reducing the amount of milk and also reducing the level of growth hormone, and as a result, caused a significant decrease in birth weights in periods 7, 14, and 21. And time of testicular descent increased significantly compared to the control group because bromocriptine is a dopamine agonist that controls the release of prolactin, which in turn regulates breastfeeding by preventing prolactin from being secreted, thereby preventing or inhibiting milk production [30]. In contrast, there was no significant difference in the level of prolactin and growth hormone after treatment with carnitine, which was reflected in the absence of a delay in the number of days of descending the testicles and the appearance of the vaginal opening compared with control.…”

Bromocriptine therapy: Review of mechanism of action, safety and tolerability

“…8 Bromocriptine has been used extensively for clinical purposes for more than 30 years for the treatment of parkinsonism, hyperprolactinemia, pituitary adenomas and galactorrhoea. [9][10][11][12][13] With the passage of time, extensive research evolved with many new potential benefits of bromocriptine such as treatment of acromegaly, 14 paripartum cardiomyopathy, 15 neuroleptic malignant syndrome (NMS), 16 extrapyramidal disorders affected by medications, diabetes mellitus 17 as well as alcohol withdrawal syndrome and much more. 18 There are also many areas in which bromocriptine is supposed to be effective, and research is ongoing in those areas with productive results in animal models, such as management of hypertension and hypercholesterolemia leading to cardiovascular complications, [19][20][21] dengue virus, 22 Zika virus, 23 etc.…”