THE ANDROGENS IN THE GUINEA-PIG FOETUS THROUGHOUT THE EMBRYONIC DEVELOPMENT

1979 ◽  
Vol 92 (1) ◽  
pp. 174-186 ◽  
Author(s):  
N. Rigaudière
Keyword(s):  
Sexual Dimorphism ◽  
Embryonic Development ◽  
Guinea Pig ◽  
Sexual Differentiation ◽  
Sharp Increase ◽  
Foetal Life ◽  
Female Foetus ◽  
High Concentrations

ABSTRACT Testosterone (T) and dihydrotestosterone (DHT) content and concentration were measured by radioimmunoassay in plasma, gonads, adrenals, and sexual ducts of 235 male and 214 female guinea-pig foetuses at various stages of gestation after gonadal and adrenal differentiation occurred. In the male foetus, a sharp increase in the content and concentration of T and, to a lesser degree of DHT, is observed in the testis, the plasma and the ducts at the time of sexual differentiation between days 28 and 36. Thereafter androgen concentrations in these tissues decrease and rise again after day 52. In the female foetus, levels of T and DHT in the ovary are low throughout foetal life and do not account for the relatively high concentrations found in the plasma; in sexual ducts, T concentrations decrease at the time of differentiation. DHT levels are low at every stage. In both sexes, T and DHT are present in the adrenal. No sexual dimorphism is observed in the evolution of T and DHT adrenal content and concentration.

Testosterone and dihydrotestosterone in amniotic fluid and foeto-placental membranes from the guinea pig

1982 ◽  
Vol 100 (2) ◽  
pp. 301-307
Author(s):  
N. Rigaudière
Keyword(s):  
Guinea Pig ◽  
Amniotic Fluid ◽  
Sexual Differentiation ◽  
Yolk Sac ◽  
Male And Female ◽  
Female Foetus ◽  
Placental Membranes ◽  
Rapid Drop

Abstract. Testosterone (T) and dihydrotestosterone (DHT) in the amniotic fluid (AF) and foeto-placental membranes (FPM) (yolk-sac + amnion) from 180 male and female guinea-pig foetuses were determined by radioimmunoassay on days 28, 32, 36, 40, 44, 48, 52, 56, 60, 64 of gestation. In male foetus the evolution of androgens in the fluid is characterized by two sharp rises, the former at the time of sexual differentiation on day 32 (T = 219.1 ± 39.1 and DHT = 74.7 ± 10.0 fmol/ml) the latter, which affects only DHT, on day 52 (DHT = 68.5 ± 10.3 fmol/ml). In female foetus, AF T concentrations (mean = 36.3 fmol/ml) are comparable to the lowest T concentrations observed in male, while DHT concentrations (< 2.5 fmol/ml), are significantly lower than those observed in the male (mean = 28.9 fmol/ml) and without any overlap in the values. Thus, in guinea pig, DHT, but not testosterone allows to predict accurately the foetal sex at any stage studied. Testosterone and DHT are also present in FPM and their concentrations were comparable for male and female foetuses in most stages, values varying between 400 and 1600 fmol/g of tissue with a light predominance of DHT compared with T; in both sexes, general evolution of androgens is marked by a rapid drop between days 28 and 44 followed by a significant increase between days 44 and 64. Possible origins of androgens in AF and FPM are discussed.

Hepatic uptake of intact glutathione S-conjugate, inhibition by organic anions, and sinusoidal catabolism

1993 ◽  
Vol 265 (3) ◽  
pp. G547-G554
Author(s):  
C. A. Hinchman ◽  
A. T. Truong ◽  
N. Ballatori
Keyword(s):  
Guinea Pig ◽  
Rat Liver ◽  
Marked Decrease ◽  
Hepatic Uptake ◽  
Half Time ◽  
High Concentrations ◽  
Rat Livers ◽  
Dose Dependent ◽  
Uptake And Metabolism ◽  
Guinea Pig Liver

To identify potential mechanisms for hepatic removal of circulating glutathione (GSH) conjugates, uptake and metabolism of S-2,4-dinitrophenylglutathione (DNP-SG) were examined in isolated perfused livers from rat and guinea pig. Guinea pig livers perfused with 5 mumol of DNP-SG in a recirculating system (50 microM initial concn) rapidly cleared the conjugate from the perfusate (half time 3.7 min), whereas clearance was considerably slower in rat liver (half time 35 min). Disappearance of DNP-SG from the perfusate was accompanied by a simultaneous appearance of DNP-SG and its metabolites in bile. Addition of acivicin, an inhibitor of gamma-glutamyltransferase (gamma-GT), to the perfusate resulted in a marked decrease in DNP-SG clearance by guinea pig liver but had no effect in rat liver, suggesting that in the guinea pig this process is largely dependent on sinusoidal gamma-GT activity. However, even in the presence of acivicin, rat and guinea pig livers removed nearly one-half of the administered DNP-SG from the recirculating perfusate over 30 min. High concentrations of DNP-SG were found in bile (up to 3.7 mM), indicating that the liver is capable of transporting the intact conjugate from the circulation. When rat livers were perfused with higher concentrations of DNP-SG (100 and 250 microM), biliary excretion of DNP-SG increased dose dependently, with concentrations in bile reaching 10 mM at the higher dose. This was accompanied by a dose-dependent choleresis.(ABSTRACT TRUNCATED AT 250 WORDS)

Sexual dimorphism in the craniofacial growth of the guinea pig (Cavia porcellus)

2004 ◽  
Vol 259 (2) ◽  
pp. 172-181 ◽  
Author(s):  
Meredith A. Farmer ◽  
Rebecca Z. German
Keyword(s):  
Sexual Dimorphism ◽  
Guinea Pig ◽  
Craniofacial Growth ◽  
Cavia Porcellus

scholarly journals Morphometric measurements for sexual dimorphism in the Campolina horse breed

2021 ◽  
Vol 56 ◽  
Author(s):  
Lisia Castro Krebs ◽  
Marina Monteiro de Moraes Santos ◽  
Maria Claudia Siqueira ◽  
Brennda Paula Gonçalves de Araujo ◽  
Leonardo Gomes Oliveira ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Discriminant Analysis ◽  
Sexual Differentiation ◽  
Analysis Of Covariance ◽  
Classification Error ◽  
Horse Breed ◽  
Linear Measurements ◽  
Morphometric Measurements ◽  
Classification Errors ◽  
Angular Measurements

Abstract: The objective of this work was to distinguish the sexual dimorphism of horses of the Campolina breed, by morphometric measurements, and to classify them according to sex, using discriminating functions. Two-hundred and fifteen horses were measured, and 39 morphometric measurements were evaluated. The analysis of covariance and the discriminant analysis were performed. Males were taller and showed a wider chest, a greater scapular-humeral angle, and a larger neck, both in length and circumference. Females had a larger heart girth, wider hips, and a greater opening of the coxal-ground and femorotibial angles. Regarding classification, circumference measurements (85.58%) were more accurate in sexual differentiation than the linear (83.26%) and angular (73.02%) ones. As to classification error, of the total animals measured, 10 to 20% of the females were categorized as males. In addition, 11 to 38% of the males were categorized as females. It can be concluded that of the 39 morphometric measurements evaluated, 22 are responsible for sexual dimorphism in the Campolina horse breed. Circumference and linear measurements provide a more assertive classification to determine sexual dimorphism. Angular measurements show greater classification errors regarding the gender of the horses.

The release of slow-reacting substance of anaphylaxis from guinea pig lung: effects of calcium antagonists

1985 ◽  
Vol 63 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Melissa A. Damiano ◽  
Edward J. Barbieri
Keyword(s):  
Guinea Pig ◽  
Intracellular Calcium ◽  
Lung Tissue ◽  
Calcium Antagonists ◽  
Lung Parenchyma ◽  
Free Medium ◽  
Bicarbonate Buffer ◽  
Normal Medium ◽  
Voltage Dependent ◽  
High Concentrations

The effects of three calcium antagonists, verapamil, lanthanum, and 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) were studied on the release of slow-reacting substance of anaphylaxis (SRS-A) from ovalbumin-sensitized chopped guinea pig lung parenchyma in calcium-containing and calcium-free media. The SRS-A levels (mean ± SEM) obtained from tissues incubated in normal and calcium-free Krebs–bicarbonate buffer were 51 ± 8 (N = 19) and 21 ± 4 (N = 14) U/mL, respectively. TMB-8 (0.1–10 μM) a reported intracellular calcium antagonist, reduced antigen-stimulated SRS-A release from lung tissue incubated in calcium-containing, but not calcium-free, medium; A23187-induced SRS-A release from normal guinea pig lung was not significantly altered by TMB-8 at concentrations up to 10 μM. Verapamil and lanthanum consistently reduced SRS-A release only at high concentrations (100 μM and 1 mM, respectively). The quantities of SRS-A released from lung tissue incubated in the presence of verapamil in normal medium were similar to those obtained in calcium-free medium. Tissues incubated in the presence of potassium chloride (60 and 100 mM) did not release significant quantities of SRS-A, and release which did occur was not blocked by verapamil, suggesting that antigen-induced SRS-A release is not dependent on membrane depolarization and that verapamil was not exerting inhibition via blockade of voltage-dependent calcium channels. These data suggest that although intracellular calcium is important for the regulation of SRS-A secretion from guinea pig lung tissue, extracellular calcium is necessary for optimal release of SRS-A.

EFFECTS OF CATIONS ON SUGAR ABSORPTION BY ISOLATED SURVIVING GUINEA PIG INTESTINE

1958 ◽  
Vol 36 (3) ◽  
pp. 347-362 ◽  
Author(s):  
E. Riklis ◽  
J. H. Quastel
Keyword(s):  
Guinea Pig ◽  
Glucose Transport ◽  
Active Transport ◽  
Glucose Absorption ◽  
Ion Concentration ◽  
Potassium Ions ◽  
Magnesium Ions ◽  
Sugar Absorption ◽  
Rate Of Absorption ◽  
High Concentrations

The rate of absorption of glucose from isolated surviving guinea pig intestine increases with increase of the concentration of glucose in the lumen until a maximum rate is obtained. The relation between absorption rate of glucose and initial glucose concentration conforms to an equation of the Michaelis–Menten type. The apparent Km(half saturation concentration) is 7 × 10−3M. Increase of the concentration of potassium ions in the Ringer–bicarbonate solution bathing the intestine leads to an increase of the rate of glucose absorption, this being most marked with 15.6 meq./liter K+and 14 mM glucose. No such stimulating action of potassium ions is observed on glucose absorption under anaerobic conditions. The effect of increased potassium ion concentration is to accelerate the rate of transport found with low concentrations of glucose to the maximum value found with high concentrations of the sugar. Sodium ions must be present for glucose absorption to take place and omission of magnesium ions from a Ringer–bicarbonate solution, containing 15.6 meq./liter K+, brings about a decreased rate of active glucose transport. Magnesium ions are necessary for the stimulated rate of glucose absorption obtained in the presence of potassium ions. The presence of ammonium ions decreases the rate of glucose absorption. Potassium ions may be effectively replaced by rubidium ions for stimulation of glucose transport. Cesium ions do not activate. The proportion of glucose to fructose appearing in the serosal solution, when fructose is absorbed from the mucosal solution, depends on the concentration of fructose present. The proportion may be as high as 9:1 with low (7 mM) fructose concentrations; it decreases with increasing fructose concentrations. The active transport of fructose, as demonstrated by the conversion of fructose in the isolated surviving guinea pig intestine, is enhanced by the presence of potassium ions (15.6 meq./liter). The rate of transport of fructose itself is unaffected by potassium. Using radioactive glucose and fructose, it is shown that the total amount of sugar transferred through the intestine as estimated by the radioactivity appearing in the serosal solution is approximately that calculated from chemical analyses. Potassium ions have no activating action on the transport of sugars such as sorbose, mannose, and D-glucosamine, but have a marked effect on galactose transport. The results support the conclusion that potassium ions do not influence active transport of glucose, fructose, and galactose by a change of intestinal permeability to these sugars, but do so by affecting a specific phase involved in the mechanism of active transport of sugars. The presence of L-glutamine stimulates active transport of glucose, whereas that of L-glutamate tends to diminish it.

scholarly journals Alternative polyadenylation coordinates embryonic development, sexual dimorphism and longitudinal growth in Xenopus tropicalis

2019 ◽  
Vol 76 (11) ◽  
pp. 2185-2198 ◽  
Author(s):  
Xiang Zhou ◽  
Yangzi Zhang ◽  
Jennifer J. Michal ◽  
Lujiang Qu ◽  
Shuwen Zhang ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Embryonic Development ◽  
Alternative Polyadenylation ◽  
Xenopus Tropicalis ◽  
Longitudinal Growth

70 GONADAL DEVELOPMENT IN GUINEA PIG MALES (CAVIA PORCELLUS)

2016 ◽  
Vol 28 (2) ◽  
pp. 164
Author(s):  
F. Oliveira ◽  
A. Santos ◽  
A. A. Neto
Keyword(s):  
Guinea Pig ◽  
Sertoli Cells ◽  
Sexual Differentiation ◽  
Primordial Germ Cells ◽  
Gonadal Development ◽  
Postnatal Period ◽  
Seminiferous Tubules ◽  
Morphological Description ◽  
Hormonal Function ◽  
Gonad Differentiation

Sexual differentiation in mammals is an event that presents many variations between species. Because it is related to hormonal function, any imbalance in the androgens and estrogens production can lead to malformations. Because sexual differentiation occurs in different ways among various animals, the recognition of their peculiarities becomes important in order to correct reproductive handling in different species. Considering that the guinea pig is commonly used as an experimental model in the reproductive area, the goal of this work was to perform a morphological description of gonad differentiation of the male guinea pig during embryonic development. In total, 11 conceptuses with ages 25 (n = 3), 30 (n = 2), 40 (n = 2), 50 (n = 2), and 65 (n = 2) days were used for light microscopy processing. The embryos at 25 days were processed completely. For the others, the gonads were dissected. The samples were dehydrated in alcohol, embedded in paraffin, and 5-µm sections were stained with hematoxylin-eosin. In the guinea pig gonad at 25 days gestation, there was a presence of gonadal cords, formed by condensation of somatic cells, which is characteristic of an undifferentiated gonad. In addition, we observed the presence of mesonephric and paramesonephric ducts in different embryos, indicating that other genital system organs were not formed. For the 30 days of development of guinea pigs, we observed that gonadal cords were differentiated in testicular cords by invasion of mesenchymal and endothelial cells, and also composed of Sertoli cells and primordial germ cells. These cords were among a large amount of testicular mesenchyme at the 40-day group. With 50- and 65-day development samples, the gonad was completely differentiated into testicle, with the presence of spermatogonia and Sertoli cells in the seminiferous tubules, and a large amount of interstitial Leydig cells around the tubules. We conclude that gonadal differentiation in guinea pig males occurs around the middle of pregnancy, between 25 and 30 days and that, before the end of the pregnancy, at 50 days, the testicle presents morphology similar to that found in the postnatal period.

scholarly journals Identity and Proliferation of Small Lymphocyte Precursors in Cultures of Lymphocyte-rich Fractions of Guinea Pig Bone Marrow

Blood ◽  
1971 ◽  
Vol 37 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Y. YOSHIDA ◽  
D. G. OSMOND
Keyword(s):  
Bone Marrow ◽  
Guinea Pig ◽  
Lymphoid Cells ◽  
Short Term ◽  
Small Lymphocyte ◽  
Undifferentiated Cells ◽  
The Mean ◽  
High Concentrations ◽  
Transitional Cells

Abstract Radioautography with 3H-thymidine was used to examine the proliferative activity of bone marrow lymphoid cells and to identify the precursor cells of small lymphocytes in short-term cultures of lymphocyte-rich marrow fractions. High concentrations of small lymphocytes (nuclear diameters less than 8.0 µ in smears) together with large lymphoid ("transitional") cells (nuclear diameters greater than 8.0 µ) were separated from suspensions of guinea pig bone marrow by centrifugation in linear sucrose-serum density gradients. When such lymphocyte-rich marrow fractions were cultured in vitro the labeling and mitotic indices following either continuous or terminal exposure to 3H-thymidine indicated that the large lymphoid cells were confined mainly to the pre-DNA-synthetic (G1) and early DNA-synthetic (S) phases at first, but proceeded subsequently through S phase and mitosis. From these data tentative values were derived for the in vitro duration of G1 (12 hours) and S (13.7 hours). Further cultures were followed radioautographically after a 1-hour pulse of 3H-thymidine at 6-7 hours of culture. The absolute numbers of labeled large lymphoid cells declined during the subsequent 21 hours but, simultaneously, labeled small lymphocytes appeared and increased progressively in absolute numbers to 44.4 ± 8.1 per cent of the initial numbers of labeled large lymphoid cells. The mean grain count of labeled small lymphocytes was half that of the initially labeled large lymphoid cells. Very few labeled undifferentiated cells other than large lymphoid cells were observed. The results demonstrate that lymphocyte-rich marrow fractions are capable of sustaining the production of small lymphocytes in short-term cultures and that the immediate precursors of marrow small lymphocytes are contained within a population of large lymphoid cells.

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