Hormonal regulation of androgen-binding protein in lamb testes

Androgen-binding protein (ABP) was measured in the testes of 50-day-old lambs. The animals were hypophysectomized and treatment lasting for 5 days was begun 15 days after surgery. In hypophysectomized but otherwise untreated lambs (control group), no 5 alpha-dihydrotestosterone binding was detectable in testicular cytosol. One out of four lambs gave a positive response with FSH treatment (25 fmol ABP/mg protein), whereas a restoration of the synthesis of ABP was noted in all LH-treated animals (19 +/- 9 (S.E.M.) fmol ABP/mg, n = 4). No synergism between the two gonadotrophins was observed in lambs treated simultaneously with FSH and LH (19 +/- 4 fmol ABP/mg, n = 5). Testosterone treatment elicited a greater response (37 +/- 9 fmol ABP/mg, n = 5) than FSH or LH alone and the response was not increased by the simultaneous addition of FSH (38 +/- 10 fmol ABP/mg, n = 5). Whatever the treatment, no influence was observed either on the number of supporting cells (undifferentiated Sertoli cells) or the length of the seminiferous tubules (P>0.05); the diameter of tubules was significantly increased in the group treated with FSH and LH. It is postulated that testosterone may have a direct effect on the production of ABP by the supporting cells of the impuberal lamb.     

Combined diagnostic value of biochemical markers in acute pancreatitis.

Eighty-three patients suffering from upper abdominal pain were studied to evaluate the contribution of commonly used biochemical markers in the diagnosis of acute pancreatitis. On admission to hospital, serum amylase, lipase, total bilirubin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and gamma-glutamyl transferase activities were measured. By stepwise logistic discrimination, only two determinations appeared to be of clinical value: lipase and alkaline phosphatase activities. A classification rule was established including these two measurements and its diagnostic performance evaluated by a jackknifed method amounted .83%. ROC curves were used to assess sensitivity and specificity. Our study clearly shows that serum lipase measurements should be preferred to amylase measurements, and that our two-test classification rule provides an efficient aid in clinical decision-making.     

The in vitro biosynthesis of steroids by the gonad of the cuttlefish (Sepia officinalis L.)

In vitro steroid biosynthesis in the male and female gonads of Sepia officinalis was investigated. Using tritium- and ¹⁴C-labeled precursors, seven enzyme systems were demonstrated: a C_20,22-lyase (cholesterol→pregnenolone), a 3β-hydroxysteroid dehydrogenase-Δ_5?4-isomerase complex (pregnenolone → progesterone; 17α-hydroxypregnenolone → 17α-hydroxyprogesterone; dehydroepiandrosterone → androstenedione), a 17α-hydroxylase (pregnenolone → 17α-hydroxypregnenolone; progesterone → 17α-hydroxyprogesterone), a C_17,20-lyase (17α-hydroxypregnenolone → dehydroepiandrosterone), a 17β-hydroxysteroid dehydrogenase (dehydroepiandrosterone → androstenediol; androstenedione → testosterone; estrone→estradiol-17β), a 20α-ol dehydrogenase (progesterone→20α-dihydroprogesterone), and a 20β-ol dehydrogenase (progesterone→20β-dihydroprogesterone). The yields were rather low (0.01–3%), except when pregnenolone was used (8%). Radioimmunoassay techniques indicate the presence of testosterone in the plasma of the cuttlefish but the absence of estrogens.     

Plasma hemoglobin. Comparison between 2 methods of determination

The methods used to titrate plasmatic haemoglobin, an analysis which is of great interest to cardiac surgery, must be very accurate because the levels are much lower than those found in whole blood. This work introduces a comparison between two methods: the ammoniacal water method and Cripps's differential method. After studying various criteria (repeatability, limit of detection, accuracy, reference values, stability of the reaction), and after studying the correlation between each method and the benzidin method, used as reference method, as well as the correlation between all of them, Cripp's method turns out to be the closest to the benzidin method, as well as being simpler, more accurate, more specific, and also easier to use than the ammoniacal water method, the only problem occurring at the stage of the preparation of the standard solution.     

Increase in the number of Kurloff cells following estrogen stimulation in guinea pigs: demonstrated latency period

The comparative study between plasma estradiol levels and KURLOFF cell numbers in the blood and some organs of adult, non pregnant female guinea-pigs, leads us to describe a biphasic response of the KURLOFF cells to estrogen stimulation. The first step, a five day lag-phase, is followed by a secondary increase of KURLOFF cell numbers with a peculiarly noticeable storage in the thymus parenchyma.     

Stimulation of adult rat Leydig cell aromatase activity by a Sertoli cell factor

The paracrine control of adult rat Leydig cell aromatase activity was investigated in vitro. After a 24-h preculture period of Percoll-purified Leydig cells (2.5-5 X 10(5) cells), 17 beta-estradiol synthesis reached a maximum at 5 h in the presence of exogenous testosterone (200 ng/ml) as substrate, with or without LH (100 ng/ml), and remained stable for a further 24 h. Aromatase activity was stimulated 2.5-fold by LH. The addition of seminiferous tubule culture medium (STM) from normal, neonatally hemicastrated, or prepubertally irradiated rats as well as Sertoli cell culture medium prepared from these animals enhanced both basal and LH-dependent aromatase activities during 5 h; this effect was diminished after 24 h of culture. When seminiferous tubules (200 mm) were cocultured with Leydig cells, a greater stimulation of 17 beta-estradiol production was observed compared to culture with STM. The association of Sertoli and germ cells with purified Leydig cells further enhanced aromatase activity. These results demonstrate that a Sertoli cell factor regulates Leydig cell aromatase activity. This factor is of proteic nature, thermolabile, has a mol wt ranging between 10,000-50,000, and is different from the LHRH-like substance. This compound is tissue and species specific, since it is not present in rat serum, other cell line media, or guinea pig and mouse STM. Its secretion is independent from FSH and testosterone controls. The stimulation of aromatase activity by this factor requires protein synthesis.     

Molybdenum content of term and preterm human milk during the first 2 months of lactation

To assess the molybdenum supply and requirements of preterm infants, Mo concentration was determined in milk from mothers of 6 term and 11 preterm newborns; no difference was found between fore- and hindmilk and no diurnal variations were found during 24-h collections. Respective values (means +/- SD) of term and preterm milks were 10.2 +/- 3.7 and 4.0 +/- 3.7 micrograms/L (106.2 +/- 38.5 and 41.7 +/- 38.5 nmol/L) at 3-5 d of lactation, 4.8 +/- 3.9 and 3.7 +/- 3.8 micrograms/L (50.0 +/- 4.6 and 38.5 +/- 39.6 nmol/L) at 7-10 d, 1.5 +/- 1.4 and 1.4 +/- 0.9 micrograms/L (15.6 +/- 14.6 and 14.6 +/- 9.6 nmol/L) at 14 d, 2.6 +/- 2.2 and 1.9 +/- 1.4 micrograms/L (27.1 +/- 22.9 and 19.8 +/- 14.6 nmol/L) at 1 mo, and 0.2 and 1.2 +/- 0.5 micrograms/L (2.1 and 12.5 +/- 5.2 nmol/L) at 2 mo. A statistical difference was found between term and preterm milk at 3-5 d of lactation. During lactation significant changes were found between the periods 3-5 d and 7-10 d, 14 d, 1 mo (p less than 0.01) and 2 mo (p less than 0.05) of lactation and between 7-10 d and 14 d (p less than 0.05). According to the requirements of the preterm infant, a supplementation of 2-3 micrograms.kg-1.d-1 by enteral route is suggested.