Menstrual disorders in patients undergoing chronic hemodialysis

OBJECTIVE

To investigate the etiology of menstrual disorders in patients undergoing chronic hemodialysis (CHD).

METHODS

The menstrual histories, along with hormonal, biochemical, and hematological data, were investigated in 25 reproductive-aged CHD patients.

RESULTS

All subjects had had regular menstrual cycles before entering CHD therapy. Of the 20 women who developed amenorrhea after beginning CHD therapy, 8 showed a return to their regular cycles and 6 improved to oligomenorrhea, 3 months to 66 months later, while 6 remained amenorrheic. The serum prolactin (PRL) levels were significantly higher in the patients (n = 9) with normogonadotropic amenorrhea or oligomenorrhea than in patients (n = 13) with regular cycles (53.6 +/- 36.2 vs 27.8 + 15.2 ng/ml, p < 0.05). The serum LH levels were high in both groups. In a cross-sectional study, the serum PRL levels gradually decreased with longer duration of dialysis.

CONCLUSIONS

Patients undergoing CHD are likely to develop menstrual disorders. Hyperprolactinemia in part contributes to these menstrual disorders. However, menstrual disorders in CHD patients tend to improve during long-term follow-up, because of the gradual decrease in serum PRL levels during long-term CHD therapy.

Central precocious puberty and chronic renal failure: a reversible condition post renal transplantation

A 3 year-old boy with chronic renal failure associated with prune belly syndrome who developed central precocious puberty is described. He had been maintained on cyclic peritoneal dialysis from age 13 months with creatinine levels of 400-600 mumol/l. Increased linear growth rate probably began at 18 months, and by 38 months of age he had testicular enlargement and pubic hair consistent with Tanner stage 2. Elevated levels of serum testosterone (3.6 nmol/l; normal < 0.7 nmol/l) and luteinizing hormone (LH) (2.8 IU/l; normal < 1.0 IU/l) were demonstrated with a pubertal response to luteinizing hormone-releasing hormone (LHRH) stimulation (peak LH 43.5 IU/l). Other endocrine tests demonstrated hyperprolactinemia (170 micrograms/l; normal 3.4-22 micrograms/l), but normal pituitary-thyroid and pituitary-adrenal functions and normal cranial MR imaging. Despite LHRH-agonist therapy with leuprolide over the next 8 months, he showed an incomplete response with only partial inhibition of basal LH and testosterone levels, and continued significant increments in height standard deviation scores (Ht-SDS) and bone age estimates. However, the sexual precocity appeared fully reversible following a successful living-related renal transplant at age 50 months. Despite discontinuation of leuprolide treatment post-operatively, there was a full reversal of his serum LH and testosterone to a prepubertal profile as well as normalization of the serum prolactin levels. Whereas most boys with chronic renal failure show delayed pubertal development and suppressed linear growth, our patient presents a unique phenomenon of reversible central precocious puberty. The effects of leuprolide therapy in the presence of a uremic milieu and the outcome of successful renal transplantation on sexual precocity are described.

Control of prolactin secretion

1. Prolactin is a 21,500 Dalton single-chain polypeptide hormone but may occur in 50 kDa and 150 kDa molecular variants. 2. These large PRL variants may be secreted predominantly; this condition is termed "macroprolactinemia". It is characterized by high immunological and normal biological serum levels of prolactin, and lack of clinical symptoms of hyperprolactinemia. 3. The information on PRL is encoded on chromosome 6. Transcription can be enhanced and suppressed by a variety of hormonal factors. 4. PRL is secreted in a pulsatile fashion; it displays a circadian rhythm (with a maximum during sleep) and is stimulated by some amino acids. PRL also responds to mechanical stimulation of the breast. 5. PRL rises during pregnancy, and maintainance of hyperprolactinemia (and, thereby, physiological infertility) is dependent on the frequency and duration of breast feedings. 6. Hypothalamic regulation of prolactin mainly involves tonic inhibition via portal dopamine. The physiological importance of various stimulating factors present in the hypothalamus is still incompletely understood. In particular, there is still no place for TRH in PRL physiology. 7. PRL is released in response to stress; this response may be mediated by opioids. The low-estrogen, low-gonadotropin amenorrhea of endurance-training women is not mediated by prolactin, however. 8. Estrogens stimulate PRL gene transcription via at least two independent mechanisms. There are many clinical examples of this estrogen effect on prolactin serum levels, and also on the growth of prolactinomas. 9. Mild hyperprolactinemia remains an enigma which cannot satisfactorily be resolved by biochemical or radiological testing. The border between "normal" and "elevated" prolactin is ill-defined. The possibility of macroprolactinemia complicates this matter even further. 10. The number of drugs which suppress prolactin by acting on pituitary D2 receptors, and which are useful in the treatment of hyperprolactinemia, continues to increase. In the field of ergot alkaloids, parenteral application appears to be a logical solution to the problem of the high first-pass effect; in addition, this form of treatment is frequently better tolerated than the oral route. 11. Prolactinoma development is presently being studied employing molecular biological techniques; the question of whether tumorigenesis can be attributed to specific defects of gene regulation remains to be answered.