Parathyroid hormone, prolactin, and function of the pituitary-gonadal axis in male patients with acute renal failure

Hyperprolactinemia as a Marker of Neurotransmitter Imbalance in Uremic Population

Serum prolactin (PRL) levels are elevated in patients with chronic renal failure (CRF) but the mechanisms responsible for these abnormalities are not fully understood. PRL secretion is undoubtedly influenced by many substances, which can be variously altered in uremia: monoamines, endogenous opiates and PTH. Our data suggest that in early renal failure PRL levels are already significantly high and the 24-h pattern of PRL secretion is significantly different from that in controls.

PRL derangements could be due in mild renal failure, to unknown factors (GABA?); in severe CRF, to a major change in dopaminergic activity; in hemodialysis (HD), to a low turnover of monoamines, and in peritoneal dialysis (PD) to increased activity of sero-toninergic and dopaminergic systems.

Characterization of a prospective human model for study of the reproductive hormone responses to major illness

With critical illness, serum testosterone levels fall markedly, whereas estrogen levels rise. Although animal studies suggest adaptive advantages, no prospective model has been available for studies in humans. We hypothesized that coronary artery bypass graft (CABG) surgery would provide such a model by eliciting the same reproductive hormone and other endocrine responses as reported with major nonsurgical illnesses. We further hypothesized that those responses would occur consistently in all CABG patients with predictable time courses, providing reliable windows for prospective studies. In 17 men undergoing CABG, serum levels of reproductive hormones, cortisol, thyroid hormones, and IGF-I were measured before and for up to 5 wk after surgery. Changes in serum levels of reproductive and other hormones were similar to those reported in nonsurgical critically ill patients. Time course for onset, duration, and recovery of reproductive hormone changes were consistent among all patients. A window for studying the testosterone and estrogen responses was established as the first 5 days following CABG. Practical use of this model was demonstrated by evaluating, in another seven men, changes in gonadotroph responsiveness to GnRH following CABG. Finally, to determine whether our findings in CABG could be extended to other surgeries, we demonstrated similar endocrine responses in 12 men following abdominal aortic aneurysm resection. We conclude that patients undergoing CABG surgery provide a useful human model for the prospective evaluation of the reproductive axis responses to acute illness. Other major surgeries are likely to also be suitable for these studies.

Prolactin secretion in kidney transplant patients

In 27 male patients with a functioning kidney transplant and in 12 healthy male subjects plasma prolactin levels were estimated under baseline, inhibitory and stimulatory conditions, respectively. Kidney transplant patients (KTP) showed normal baseline plasma levels of prolactin, and a normal response of prolactinaemia to alpha-bromocriptine. In contrast, administration of chlorpromazine was followed by an exaggerated response of prolactin secretion in KTP as compared with normals. Type of immunosuppressive therapy (cyclosporine A or azathioprine) did not influence significantly the plasma prolactin profile in KTP under either inhibitory or stimulatory conditions.

Bioactive luteinizing hormone in plasma of uraemic men and men with primary testicular damage

Elevation of immunoreactive LH and reduced testosterone production are consistent features of Leydig cell dysfunction in uraemic hypogonadism. To investigate further Leydig cell regulation in uraemia, we measured plasma bioactive LH (B-LH) and immunoreactive LH (I-LH), as well as FSH, testosterone, creatinine, urea and albumin in seven uraemic men before and after haemodialysis and compared them to levels both in eugonadal controls (n = 10) and in men with primary testicular damage (n = 10). Plasma B-LH was increased in uraemic men compared with both nonuraemic control groups. Plasma I-LH and FSH were increased and testosterone decreased in uraemic men compared to eugonadal controls. In comparison with nonuraemic men with primary testicular damage, plasma I-LH levels were similar but FSH and testosterone lower in uraemic men. As a consequence, the ratio of B-LH to I-LH (LH:B/I ratio) was decreased in men with primary testicular damage but normal in uraemic men. A single session of haemodialysis decreased creatinine (50.5%) and urea (58.5%) and increased B-LH (47.7%), I-LH (32.9%), FSH (24.4%), testosterone (15.8%) and albumin (17.8%) levels, but the LH:B/I ratio was unchanged. Increases in gonadotrophin levels were greater than could be accounted for by haemoconcentration suggesting that dialysis may also ameliorate uraemic suppression of the hypothalamus and pituitary. Ultrafiltrates of human uraemic plasma (mol wt less than 25 000) had no inhibitory effect on in-vitro steroidogenesis by isolated rat Leydig cells making circulating uraemic 'middle-molecule'-type toxins unlikely to be involved in causing lowered testosterone levels in uraemic men.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of 1,25-dihydroxyvitamin D3 on plasma prolactin in patients with renal failure on regular dialysis treatment

Basal plasma prolactin (PRL) has been measured in 6 patients with chronic renal failure 3 months before and at monthly intervals during a 3 months 1,25-dihydroxyvitamin D3 [1,25 (OH)2-D] treatment. Plasma PRL decreased rapidly during, 1,25 (OH)2-D treatment, while it remained unchanged during the 3-months control period. There was no correlation between PRL and parathyroid hormone (PTH; measured either with carboxy- or amino-terminal assays) and several other parameters. A direct effect of 1,25 (OH)2-D on PRL secretion may exist.