Antecubital Plasma Research Articles

Serotonin, catecholamines, and spontaneous midgut carcinoid flush: Plasma studies from flushing and nonflushing sites

Background/Aims : Serotonin is the diagnostic hallmark of midgut carcinoids, but the pathophysiology of spontaneous flushing is unknown. The aim of this study was to assess to what extent serotonin and catecholamine blood levels are related in time with spontaneous midgut carcinoid flush. Methods : Using specific radioenzymatic assays, we measured prospectively before, during, and after spontaneous flushing platelet-poor plasma and whole blood serotonin and plasma catecholamines and their metabolites in 10 patients with primary midgut carcinoids. Blood was drawn simultaneously from a forearm vein and an external jugular vein draining the flushing area. Results : During flushing, plasma serotonin and norepinephrine levels increased ( P < 0.001) over preflush levels at both sampling sites. Intraflush serotonin and norepinephrine were twice as high ( P < 0.01) in external jugular (9.57 ± 1.40 ng/mL and 857 ± 33 pg/mL, respectively) than in antecubital plasma (4.59 ± 0.73 ng/mL and 471 ± 26 pg/mL). Preflush and postflush levels were similar at both venous sites. Conclusions : Vein plasma serotonin and norepinephrine levels do increase during midgut carcinoid flush, especially in the flushing area. This may reflect a local release secondary to flush but also suggests a role for these bioamines in the pathogenesis of flushing.

Hormone levels in the reproductive system of normospermic men and patients with oligospermia and varicocele.

The endocrine milieu on which spermatogenesis and sperm maturation mainly depend was evaluated quantitatively with simultaneous measurements of FSH, LH, PRL, testosterone, estrone, estradiol (E2), and sex hormone-binding globulin concentrations in spermatic venous plasma, antecubital plasma, seminal fluid, and wash fluid from vas deferens in 16 normospermic men and 24 oligospermic patients. Anesthesia and surgical stress caused a rise of only PRL and E2 (P less than 0.001-0.01). Mean FSH, LH, and PRL levels were comparable in antecubital and spermatic venous plasma, and antecubital values were higher in oligospermic patients for FSH and LH (P less than 0.05-0.001). Mean (+/- SD) T levels were similar for normospermic and oligospermic men in spermatic venous plasma (473 +/- 75 and 439 +/- 270 ng/ml), in antecubital plasma (6.5 +/- 1.3 and 6.6 +/- 1.8), and in seminal fluid (0.3 +/- 0.1 for both). Minute quantities of testosterone were detected in pooled wash fluid (0.08 ng). For E2, similar concentration gradients from high to low levels were found in normospermic and oligospermic men (spermatic venous plasma = 926 +/- 205 pg/ml and 1090 +/- 262; antecubital plasma = 31.0 +/- 12.0 and 28.4 +/- 1.9; seminal fluid = 14.3 +/- 2.3 and 12.0 + 2.8). Estrone was also high in spermatic venous and low in antecubital plasma but higher in seminal fluid than in antecubital plasma. Sex hormone-binding globulin levels were slightly though not significantly lower in spermatic venous (23 +/- 10 nmol/liter) than in antecubital plasma (28 +/- 6), but not measurable in seminal fluid. These results define important aspects of the endocrine milieu prevailing in the male reproductive tract and demonstrate a change of the relative activity of androgens and estrogens from the testis to the seminal fluid.