Miyao Matsubara

RELATIONSHIP OF CHANGES IN SERUM CONCENTRATIONS OF PROLACTIN AND TESTOSTERONE DURING DOPAMINERGIC MODULATION IN MALES

To evaluate the effect of PRL on the male pituitary‐gonadal system, serum concentrations of PRL, testosterone, LH and FSH were determined in healthy young men daily before, during, and after 3‐day oral administration of bromocriptine, metoclopramide or sulpiride. Bromocriptine (2.5 mg as a single dose) caused, concurrently with a marked suppression of serum PRL, a significant increase of serum testosterone and a transient decrease of serum LH. The changes of PRL and testosterone were negatively correlated. With metoclopramide (10 mg q.i.d.) serum PRL was increased and testosterone inversely decreased. There was no change in LH and FSH. Sulpiride (50 mg q.i.d.) evoked the elevation of serum PRL and LH, but no change in testosterone. A significant increase in serum concentration of testosterone was also observed in a patient with PRL‐producing pituitary tumour and four out of seven patients with acromegaly during bromocriptine treatment. These results suggest an inhibitory effect of PRL on testosterone secretion at the gonadal level, or direct dopaminergic stimulatory control of testosterone secretion.

Relationships between plasma adiponectin and blood cells, hepatopancreatic enzymes in women.

Adiponectin, which is secreted specifically from adipocyte, is thought to play a key role in the metabolic syndrome. We studied the associations of plasma adiponectin concentrations with blood cells and hepatopancreatic enzymes in 339 women aged 54.0 +/- 0.8 (mean +/- SE) years. Plasma adiponectin before and after adjustment for body composition or calculated insulin resistance increased in slight anemic women (372.6 +/- 2.6 x 10(4)/mm3) compared with non-anemic subjects (471.1 +/- 1.7) (all p < 0.0001), and were inversely associated with red blood cells (RBC), hemoglobin, hematocrit, white blood cells and platelet values (p < 0.0001-0.02), independent of age, diastolic blood pressure, body mass index, serum triglyceride, insulin resistance or blood urea nitrogen. Age and adiponectin/body fat mass (%) were negative, and blood pressure and insulin resistance were positive significant independent determinants of RBC in step-wise regression analysis. Moreover, adiponectin before and after adjustment were inversely associated with serum ALAT, gammaGTP and ChE, and positively with amylase levels (p < 0.0001-0.02). These results indicate the possibility that increased adiponectin may contribute to the suppressive bone marrow function in vivo. Combined with the leptins data, adipocyte derived proteins were related to the hematopoiesis, therefore it has shown the possible existence of adipose tissue/ bone marrow function linkage more clearly. Furthermore, hepatopancreatic enzyme associations with this protein may indicate the possibility that adiponectin will regulate the hepatopancreatic function in health and disease.

Effect of ageing on plasma lipoprotein(a) levels

Background Lipoprotein(a) [Lp(a)] is a risk factor for atherosclerosis and increases with age. The purpose of this study was to determine the effect of ageing on Lp(a) for three different apo(a) phenotypes. Methods We measured plasma Lp(a) concentrations in 551 unrelated Japanese subjects (20-88 years of age). We performed statistical analyses separately for three apo(a) phenotypes: the low-molecular-weight (LMW) phenotype with the F, B or S1 isoform, the intermediate-molecular-weight (IMW) phenotype with the S2 isoform and the high-molecular-weight (HMW) phenotype with the S3 or S4 isoform. Results For each phenotype, the mean plasma Lp(a) concentration and the frequency of Lp(a) concentrations ≥ 250 mg/L increased with age. Further, a statistically significant difference was always found between the younger subjects (20-39 years of age) and the elderly (over 60 years). The frequency of coronary heart disease increased with age, particularly for the LMW and IMW phenotypes. Conclusions We conclude that ageing elevates plasma Lp(a) concentrations, which may have a role in the prevalence of coronary heart disease in the elderly, especially those with the LMW or IMW phenotypes.

The Significance of the Measurement of Plasma Transferrin as a Growth Factor

The concentrations of plasma transferrin (Tf), which has been described as possessing growth promoting activity in vitro, were determined in patients with various endocrine diseases before and after treatment. Plasma Tf levels in 74 healthy subjects were 269 +/- 3 (mean +/- SE) mg/dl. In 11 patients with active acromegaly, they were elevated to 353 +/- 11 mg/dl (p less than 0.001), while they were reduced to 168 +/- 14 mg/dl in 8 patients with hypopituitarism (p less than 0.001). They were normalized after treatment. These data indicate that plasma Tf varies according to the endocrine conditions with good correlation of the status of plasma somatomedin C, and therefore its measurement may be useful clinically for the evaluation of the status of growth factors. However, the values should be assessed carefully in cases with proper Tf abnormalities, such as hematological, hepatic, or renal disorders.