Iron tissue storage and hemoglobin levels of deficient rats repleted with iron bound to the caseinophosphopeptide 1-25 of beta-casein.

Caseinophosphopeptides (CPP) issued from enzyme digestion of caseins bind cations and keep them soluble in the digestive tract. They could be used as ligands to improve iron (Fe) bioavailability. Fe-deficient young rats were repleted with Fe (40 or 200 mg/kg of diet) bound either to the beta-CN (1-25) of beta-casein or to whole beta-casein or as FeSO(4).

Oct3/4-associating proteins from embryonal carcinoma and spermatogenic cells of mouse.

The octamer-binding protein Oct3/4 was postulated to active transcription through protein-protein interactions with hypothetical cellular coactivator(s). We have used a bacterially produced Oct3/4, as a protein-binding probe, to detect by far-Western assay the Oct3/4-associating proteins (OTAPs) from the embryonal carcinoma (EC) cells F9 and pachytene spermatocytes. Both common and cell-specific OTAPs were shown to interact directly with Oct3/4.

Relationships between iron and zinc metabolism: predictive value of digestive absorption on tissue storage.

The responses of animals to intake of a trace element could vary if it is ingested with a single test meal or due to chronic intake. The metabolic relationships between zinc (Zn) and iron (Fe) were assessed in the young animal by comparing their digestive absorption studied at the beginning of the study with their tissue storage after two months of being fed on experimental diet. Diets supplied adequate intakes of Fe (45 and 300mg/kg diet) and Zn (14 and 45 mg/kg).

Effect of small variations of aluminum intake on calcium metabolism in young rats.

Background: While in the adult Al intoxication requires high dosages, little is known on the threshold level of Al toxicity in the young.

Methods: Weaning rats were fed for 90 days ore of four diets differing by their content in Ca (7.5 vs < 0.

In vitro effects of Celiptium and MR 14504 on mature rat Leydig cell testosterone production.

Percoll-purified mature rat Leydig cells have been used to evaluate the testicular toxicity of two highly potent intercalating agents (Celiptium and MR 14505). Testosterone secretion in the absence and in the presence of human chorionic gonadotropin (hCG) was measured to assess Leydig cell function. Celiptium and MR 14504 induce time- and dose-related inhibitory effects on the production of testosterone by Leydig cells, both in the presence and in the absence of hCG, whatever the concentration of hCG used.

Equine cytochrome P450 aromatase exhibits an estrogen 2-hydroxylase activity in vitro.

Aromatase (estrogen synthetase) is a steroidogenic enzyme complex which catalyzes the conversion of androgens to estrogens (termed aromatization). This enzyme was purified from adult equine testis to homogeneity by five chromatographic steps. The ability of purified and reconstituted equine aromatase to exhibit an estrogen 2-hydroxylase activity was tested and compared to testosterone aromatization.

Enzymatic properties of adult human Sertoli cells in vitro.

The adult human Sertoli cells produced lactate, estradiol-17beta, transferrin and inhibin; germ cells modulate synthesis of these compounds. In order to study the functional features of human Sertoli cells in vitro, the aim of this study was to measure the lactic dehydrogenase (LDH), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP) and creatine kinase activities (CK) in primary cultures of Sertoli cells prepared from young men (mean age: 29 years, n = 11). Five LDH isozymes have been found in Sertoli cells, the main fractions being the LDH3 and LDH4; each of them represented 30% of the total LDH activity.

Determination of metallothioneins by HPLC: application to zinc metabolism.

Metallothioneins (MT) are well known Zn and Cu tissue proteins. Their level is mainly regulated by Zn. Therefore, they have been suggested as an index of Zn status.

Postprandial lipoprotein metabolism in normotriglyceridemic non-insulin-dependent diabetic patients: influence of apolipoprotein E polymorphism.

Non-insulin-dependent diabetes mellitus (NIDDM) is associated with postprandial lipoprotein clearance defects that are correlated with the fasting hypertriglyceridemia widely observed in NIDDM patients. The aim of this study was to determine if such postprandial disturbances are found in NIDDM patients strictly normotriglyceridemic in the fasting state, and if the apolipoprotein E (apo E) polymorphism influences postprandial metabolism of intestinally derived lipoproteins. The vitamin A-fat loading test was used in 18 normotriglyceridemic NIDDM patients and seven normotriglyceridemic obese controls, and postprandial triglyceride (TG) and retinyl palmitate (RP) concentrations were evaluated in total plasma, and in the chylomicron (Sf > 1,000) and nonchylomicron (Sf < 1,000) fractions isolated by ultracentrifugation.

Germ cell and Sertoli cell interactions in human testis: evidence for stimulatory and inhibitory effects.

In human Sertoli cell preparations obtained from healthy men (mean age 31.8 +/- 6.8 years; n = 6), we have measured the productions of lactate, 17 beta-oestradiol, transferrin and inhibin between day 4 and day 5 after plating, either in the presence or absence (hypotonic treatment of plated cells on day 2) of germ cells.

Steroidogenesis in the two enriched-Leydig cell populations of human testis: evidence for a positive control by seminiferous tubules secreted factor(s).

In two different enriched populations of Leydig cells (called FI and FII) obtained from human testes (young patients: mean age 36 +/- 3 years, n = 6; aged men: mean age 73 +/- 2 years, n = 5), the dehydroepiandrosterone and testosterone in vitro outputs were increased in a dose- and time-related manners by hCG. Similar results were obtained when the Leydig cells were incubated in presence of either dbcAMP or 22R-hydroxycholesterol. In presence of either hCG or dbcAMP, the coefficient of stimulation (in terms of steroid outputs) was higher in FII when compared to FI.

[Sertoli cells. Functional aspects compared in rats, pigs and man].

In the mammalian testis, the Sertoli cell plays a key role in the development and maintenance of spermatogenesis. Indeed, within the seminiferous tubule, the structure of the Sertoli cells and the specialized junctions between them and the neighbouring germ cells, contribute to create the sophisticated microenvironment and to bring all the nutriments require for a full development of germ cells. In this review, we have compared the main Sertoli cell functions in the rat and the pig to the available data concerning the human.

[Physiological variations of LpA1, HDL2 and principal lipid markers in athletes].

An original approach of the influence of physical activities on lipid metabolism is presented in this work: the authors studied the physiological variations of the lipoparticle LpA1, high-density lipoprotein subfraction HDL2 and the most important lipid markers in serum of a presumably healthy population of 55 high-level sportsmen. They were 18-45 years old and practised endurance sports, whether individual (cycling, long-distance running), or collective activities (soccer, basketball). The authors observed an important increase of LpA1 (+20%, p < 0.

Chromium and parenteral nutrition in children.

Chromium (Cr) dosage was assayed in i.v. nutrition, serum, and losses of five children on total parenteral nutrition for > or = 4 weeks.

Human Sertoli cells in vitro. Lactate, estradiol-17 beta and transferrin production.

Human Sertoli cell parameters, namely lactate, estradiol-17 beta, and transferrin production, were determined after a 24-hour incubation with either human follicle stimulating hormone (FSH) or dbcAMP in the presence or absence of testosterone plus a phosphodiesterase inhibitor (1-methyl-3-isobutylxanthine; MIX). Testicular tissues were obtained from 10 young patients (mean age, 29 years); using a 3-step enzymatic treatment, Sertoli cell enriched preparations (> 92%) were studied after 4 days as primary cultures. No significant changes in lactate, estradiol-17 beta, and transferrin outputs have been observed according to age in patients ranging in age from 16 years to 47 years.

Germ cell-Sertoli cell interactions and production of testosterone by purified Leydig cells from mature rat.

The addition of seminiferous tubule (ST) culture medium (STM) prepared from testes of either busulfan-treated (Bus) or cryptorchid (Cryp) or genetically sterile (hd) rats, to Percoll purified Leydig cells leads to a further increase of LH-stimulated testosterone (T) output (26, 43 and 14%, respectively). Taking into account that the Sertoli cell number per cm of ST is 2.6, 1.

Plasma chromium concentrations in normal infants and cystic fibrosis patients.

Plasma Cr concentrations have been studied in normal children aged 0-14 yr. Levels ranged from 0.65 to 0.

Chromium status of full-term and preterm newborns.

In order to obtain reference values from normal babies, Cr status of full-term newborns has been studied. Plasma and urine values were (mean +/- SEM) 0.7 +/- 0.

Age-related changes in the function of the pituitary-gonadal axis in a sterile male rat mutant (hd/hd).

Testicular growth is depressed in the genetically sterile male rat (hd/hd) relative to its LE phenotype littermates (by 50% and 73% at 27 and 90 days of age, respectively). Within the hd/hd testis, both the tubular and seminiferous tubule tissues are affected by the mutation. In addition, there is significantly less germ cell production from the primary spermatocyte stage of spermatogenesis onwards and the total number of Sertoli cells observed is less.

[Value of the study of total alkaline phosphatases and bone isoenzyme in a population of subjects with osteoporosis].

The authors have compared the values of total and bone serum alkaline phosphatases in an osteoporotic population and a control group. The total activity of alkaline phosphatases was determined by a kinetic method at 30 degrees C and alkaline phosphatase isoenzymes were separated by agarose gel electrophoresis in presence or absence of wheat germ lectin. The authors have confirmed reported data concerning the physiological variations of alkaline phosphatases in the control group; they have therefore divided each group in several sub-populations according to age and sex in order to obtain accurate comparisons.

Evidence for LH-inhibiting activity in ovine peripheral and testicular blood.

Intracellular cyclic AMP and testosterone productions by purified mature rat Leydig cells were stimulated by oLH (25 micrograms/l) 18- and 12-fold, respectively, after a 5-h incubation period. The replacement of the incubation medium by charcoal-treated testicular venous plasma (40%, v/v) from adult rams in the breeding season induced an inhibition of cyclic AMP and testosterone productions (82 and 66%, respectively, of oLH-stimulated values). Testicular arterial plasma is less effective than testicular venous plasma, even when it originates from non-breeding season rams; in that case, testicular venous and arterial plasma strongly inhibit testosterone productions (84 and 67%, respectively of oLH-stimulated values), which probably indicates that the inhibitory activity is higher in the non-breeding season.