Differences in properties of the sheep testicular LH and FSH receptors

1991 ◽  
Vol 6 (3) ◽  
pp. 291-297 ◽  
Author(s):  
T. A. Yarney ◽  
M. R. Sairam
Keyword(s):  
Structural Properties ◽  
Mammalian Species ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Cross Linking ◽  
Fsh Receptor ◽  
Optimum Temperature ◽  
Lh Receptor ◽  
Marked Preference

ABSTRACT Differences in binding and structural properties of ovine testicular FSH and LH receptors were investigated. The ovine FSH receptor did not discriminate between FSH of different species, although equine FSH was more reactive. In the same tissue, however, the LH receptor showed marked preference for ovine and bovine LH, reacting very weakly with other preparations of pituitary LH. Human chorionic gonadotrophin also reacted partly with the ovine LH receptor at 25 °C. However, at 4 °C. the optimum temperature for binding of the LH receptor to its homologous hormone, the receptor displayed no recognition for chorionic gonadotrophin preparations. Affinity cross-linking studies with ovine testicular membrane suggested that the ovine FSH receptor has an Mr of 70 000, which is very similar to that observed in the porcine ovary. The Mr of the ovine LH receptor was estimated to be 150 000, which is different from those of other mammalian species, including those that have been cloned. The data suggest that the binding and structural properties of the ovine FSH receptor are similar to those of other mammalian FSH receptors, whereas the ovine LH receptor appears to differ from other mammalian LH receptors in having a different Mr and in being more stringent in its requirement for pituitary LH.

Studies on primate gonadotropin receptors: comparison of follitropin and lutropin receptors in human testis

1983 ◽  
Vol 61 (7) ◽  
pp. 561-568 ◽  
Author(s):  
M. I. Berman ◽  
M. R. Sairam
Keyword(s):  
Dissociation Constants ◽  
Specific Binding ◽  
Particulate Fraction ◽  
Human Testis ◽  
Fsh Receptor ◽  
Lh Receptor ◽  
Adult Men ◽  
Human Choriogonadotropin ◽  
Marked Preference ◽  
Old Men

The interaction of 125I-labeled human follitropin (hFSH), human lutropin (hLH), and human choriogonadotropin (hCG) with a particulate fraction prepared from the testes of adult men was investigated. The hormone specific binding was maximal at pH 7.5 and 34 °C in the presence of 10 mM MgCl2. The FSH receptor was relatively more stable than the LH receptor (t1/2 at 34 °C of 14 and 4 h, respectively). The dissociation constants (Kd) calculated for hLH or hCG were very similar (approximately 1.0 × 10−10 – 1.4 × 10−10 M). The affinity of FSH and LH to their receptors did not appear to change with age, as shown from analysis of testes from 17- to 80-year-old men. The number of FSH receptors was greater than the number of LH receptors in these tissues. The hFSH receptor did not show any preference to binding of the homologous hormone, because FSH from nonprimates could displace 125I-labeled hFSH, but the LH receptor showed a marked preference for hLH or hCG as the ligand.

Luteinizing hormone receptor mutations and sex differentiation

1996 ◽  
Vol 134 (5) ◽  
pp. 533-540 ◽  
Author(s):  
Axel PN Themmen ◽  
Han G Brunner
Keyword(s):  
Luteinizing Hormone ◽  
Hormone Receptor ◽  
Sex Differentiation ◽  
Receptor Gene ◽  
Present Knowledge ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Luteinizing Hormone Receptor ◽  
Lh Receptor ◽  
Inactivating Mutations

Themmen APN, Brunner HG. Luteinizing hormone receptor mutations and sex differentiation. Eur J Endocrinol 1996;134:533–40. ISSN 0804–4643 Mutations in the luteinizing hormone (LH) receptor gene have been found in patients with abnormalities in their sexual differentiation. In this paper we review results obtained in the studies of these LH receptor mutations. Activating and inactivating mutations are discussed with respect to the mechanism of action of LH/human chorionic gonadotrophin but also in light of their impact of the present knowledge of the physiology of sex differentiation and gonadal function. APN Themmen, Department of Endocrinology and Reproduction, Erasmus University Rotterdam, 3000 DR Rotterdam, The Netherlands

ANDROGENS AND RELATED COMPOUNDS IN THE SPERMATIC VEIN BLOOD OF DOMESTIC ANIMALS

1961 ◽  
Vol 23 (2) ◽  
pp. 171-NP ◽  
Author(s):  
H. R. LINDNER
Keyword(s):  
Mammalian Species ◽  
Venous Blood ◽  
Blood Stream ◽  
Domestic Animals ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Spermatic Vein ◽  
Peripheral Venous Blood ◽  
Secretory Products ◽  
Related Compounds

SUMMARY Testosterone and androstenedione were identified in the spermatic vein blood of the ram, the boar and the stallion. Neither of the two steroids could be detected in the arterial or peripheral venous blood, indicating that testosterone and androstenedione are secretory products of the testis in the three species studied. Small amounts of testosterone (14–20 μg./hr.) were secreted by the testes of the young ram and boar already at the age of 3½ months. The testes of the mature boar are capable of releasing testosterone into the blood stream at the rate of 184–716 μg./hr. On the basis of these findings it is suggested that testosterone constitutes the principal testicular androgen in the boar. This conclusion differs from the view expressed by earlier investigators with respect to the boar, but is consistent with the results obtained in all other mammalian species thus far examined. Intravenous administration of human chorionic gonadotrophin (2–15 i.u./kg.) was followed by a prompt increase in the rate of testicular secretion of androgen in most of the experimental animals; however, this observation requires confirmation, in view of the limited number of experiments carried out.

Enzymatic removal of asparagine-linked carbohydrate chains from heterodimer human chorionic gonadotrophin and effect on bioactivity

2007 ◽  
Vol 19 (8) ◽  
pp. 933 ◽  
Author(s):  
Craig A. H. Richard ◽  
Mitchell D. Creinin ◽  
Carolyn J. Kubik ◽  
Julie A. DeLoia
Keyword(s):  
Direct Evidence ◽  
Anticancer Therapy ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Native Form ◽  
Lh Receptor ◽  
Human Granulosa Cells ◽  
Emergency Contraceptive ◽  
Ectopic Pregnancies ◽  
Carbohydrate Chains

The native form of human chorionic gonadotropin (hCG) is a heterodimer protein with two asparagine (Asn)-linked carbohydrate chains on each subunit. Removal of the Asn-linked carbohydrate chains from hCG has resulted in hCG variants with consistent antagonistic properties on isolated murine cells. Specific and direct enzymatic removal of these carbohydrate chains from native hCG with resultant antagonistic properties has not been reported. An antagonist to the hCG/luteinising hormone (LH) receptor could be used as an anticancer therapy, emergency contraceptive or for therapeutic resolution of ectopic pregnancies. Therefore, our aim was to use enzymes to specifically remove Asn-linked carbohydrate chains from hCG in the heterodimer form and analyse the resultant bioactivity. Native hCG was treated with endoglycosidases, carbohydrate removal was analysed with electrophoresis and the hCG variants were tested for altered bioactivity with human and murine cells. Endoglycosidases were able to cleave most of the Asn-linked carbohydrate chains from the native hCG. The deglycosylated hCG demonstrated a 75% reduction in bioactivity on a murine Leydig cell line and a 65% reduction in bioactivity on human granulosa cells. These results exemplify a simple and efficient method for creating deglycosylated hCG and provide the most direct evidence for the importance of Asn-linked carbohydrate chains in maintaining hCG bioactivity.

Diversity of Primary Structures of the Carboxy-terminal Regions of Mammalian Fibrinogen Aα-Chains

1993 ◽  
Vol 69 (04) ◽  
pp. 351-360 ◽  
Author(s):  
Masahiro Murakawa ◽  
Takashi Okamura ◽  
Takumi Kamura ◽  
Tsunefumi Shibuya ◽  
Mine Harada ◽  
...  
Keyword(s):  
Amino Acid ◽  
Rhesus Monkey ◽  
Syrian Hamster ◽  
Tandem Repeats ◽  
Mammalian Species ◽  
Amino Acid Sequences ◽  
Point Of View ◽  
Cross Linking ◽  
Amino Terminal ◽  
Rgd Sequence

SummaryThe partial amino acid sequences of fibrinogen Aα-chains from five mammalian species have been inferred by means of the polymerase chain reaction (PCR). From the genomic DNA of the rhesus monkey, pig, dog, mouse and Syrian hamster, the DNA fragments coding for α-C domains in the Aα-chains were amplified and sequenced. In all species examined, four cysteine residues were always conserved at the homologous positions. The carboxy- and amino-terminal portions of the α-C domains showed a considerable homology among the species. However, the sizes of the middle portions, which corresponded to the internal repeat structures, showed an apparent variability because of several insertions and/or deletions. In the rhesus monkey, pig, mouse and Syrian hamster, 13 amino acid tandem repeats fundamentally similar to those in humans and the rat were identified. In the dog, however, tandem repeats were found to consist of 18 amino acids, suggesting an independent multiplication of the canine repeats. The sites of the α-chain cross-linking acceptor and α2-plasmin inhibitor cross-linking donor were not always evolutionally conserved. The arginyl-glycyl-aspartic acid (RGD) sequence was not found in the amplified region of either the rhesus monkey or the pig. In the canine α-C domain, two RGD sequences were identified at the homologous positions to both rat and human RGD S. In the Syrian hamster, a single RGD sequence was found at the same position to that of the rat. Triplication of the RGD sequences was seen in the murine fibrinogen α-C domain around the homologous site to the rat RGDS sequence. These findings are of some interest from the point of view of structure-function and evolutionary relationships in the mammalian fibrinogen Aα-chains.

THE PRECISION OF THE OVARIAN ASCORBIC ACID DEPLETION TEST FOR LUTEINIZING HORMONE

1963 ◽  
Vol 43 (1) ◽  
pp. 155-160
Author(s):  
Jørgen Falck Larsen ◽  
Christian Hamburger
Keyword(s):  
Ascorbic Acid ◽  
Luteinizing Hormone ◽  
Clinical Analysis ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin

ABSTRACT Various modifications of the Parlow test for luteinizing hormone (ovarian ascorbic acid depletion in rats) were tried. Human chorionic gonadotrophin was used instead of hypophyseal luteinizing hormone. The precision of the method was found to be so low, however, that the test could not be used for routine clinical analysis. The low precision found in this and other laboratories is thought to be due to the strains of rats used.

STUDIES ON THE AROMATISATION OF NEUTRAL STEROIDS IN PREGNANT WOMEN

1964 ◽  
Vol 45 (4) ◽  
pp. 535-559 ◽  
Author(s):  
E. Bolté ◽  
S. Mancuso ◽  
G. Eriksson ◽  
N. Wiqvist ◽  
E. Diczfalusy
Keyword(s):  
Pregnant Women ◽  
Comparative Studies ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Radioactive Material ◽  
Placental Barrier ◽  
Therapeutic Abortion ◽  
Limited Ability ◽  
Better Than

ABSTRACT In 15 cases of therapeutic abortion by laparotomy the placenta was disconnected from the foetus and perfused in situ with tracer amounts of radioactive dehydroepiandrosterone (DHA), dehydroepiandrosterone sulphate (DHAS), androst-4-ene-3,17-dione (A), testosterone (T) and 17β-oestradiol (OE2). Analysis of the placentas, perfusates and urine samples revealed an extensive aromatisation of DHA, A and T; more than 70% of the radioactive material recovered was phenolic, and at least 80 % of this phenolic material was identified as oestrone (OE1), 17β-oestradiol (OE2) and oestriol (OE3), the latter being detected only in the urine. Comparative studies indicated that A and T were aromatised somewhat better than DHA and that all three unconjugated steroids were aromatised to a much greater extent than DHAS. Radioactive OE1 and OE2 were isolated and identified in the placentas and perfusates, but no OE3, epimeric oestriols, or ring D ketols could be detected in these sources, not even when human chorionic gonadotrophin (HCG) was added to the blood prior to perfusion. Lack of placental 16-hydroxylation was also apparent when OE2 was perfused. Regardless of the precursor perfused, there was three times more OE2 than OE1 in the placenta and three times more OE1 than OE2 in the perfusate. This was also the case following perfusion with OE2. The results are interpreted as suggesting the existence in the pregnant human of a placental »barrier« limiting the passage of circulating androgen. The barrier consists of a) limited ability to transfer directly DHAS and b) an enzymic mechanism resulting in the rapid and extensive aromatisation of the important androgens DHA, A and T.

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