The heterogeneity of rat androgen-binding protein in serum differs from that in testis and epididymis

Fractionation of testicular, epididymal, and serum extracts containing rat androgen-binding protein (rABP) on a Concanavalin A-Sepharose (Con A) column resolved two peaks of immunoreactive protein. The first peak was present in the void volume, and the other was bound by the column and specifically eluted by alpha-methyl-D-glucoside. These two peaks of immunoreactive rABP have been designated form I and form II for the portions of rABP that do not and do bind, respectively, to Concanavalin A. In the course of studying this heterogeneity, we observed that the distribution of the two forms of rABP was the same in the blood and cytosols prepared from testis and epididymis of young rats before the formation of the blood-testis barrier; that is, the ratio of form I to form II ranged from 1:1 to 1:2. Similar heterogeneity was observed in extracts of the reproductive tract from mature animals. However, the blood of adult rats contained reduced amounts of form I relative to form II, so that their ratio was about 1:5. Subsequent studies of infertile rats heterozygous for the Hre gene (Hre/ +), in which total rABP secretion was decreased, and of their normal littermates, indicated that the reduced amount of form I ABP in the sera of mature rats is typical of adult animals regardless of strain or genetic abnormality. The reduced amount of form I relative to form II observed in the blood of adult rats could result from either reduced secretion or increased metabolic clearance of form I in the blood compartment. To distinguish between these possibilities, the blood clearance of the two forms was estimated after orchiectomy. The disappearance rate of form I was not significantly different from that of either form II or unfractionated serum. These results are consistent with reduced release into blood of form I relative to form II rABP rather than increased clearance of form I in adult animals.

Human testicular androgen-binding protein shares immunodeterminants with serum testosterone-estradiol-binding globulin

In the human, there are two glycoproteins, testosterone-estradiol-binding globulin (hTeBG) and androgen-binding protein (hABP), which bind testosterone. Although these two proteins have similar physicochemical properties, they can be distinguished on the basis of origin and lectin binding. hTeBG is made in the liver and exhibits high affinity for Concanavalin A (Con A), while hABP from the testes is only partially bound to this lectin. That is, when testicular extracts were applied to Con A-Sepharose columns, a portion of the testosterone-binding material showed no interaction with the lectin and eluted in the void volume (peak I), while the remainder interacted strongly and could be eluted with alpha-methyl-D-glucoside (peak II). These observations are consistent with the proposal that peak I contains only hABP, whereas peak II contains hTeBG and/or hABP with carbohydrate units that permit binding to Con A. To further study the properties of these binding proteins, a hTeBG RIA using a monospecific antiserum was employed to compare the proteins in testes and serum. The results indicated that the testosterone-binding activities in peaks I and II of testicular extracts could not be distinguished immunologically from hTeBG in sera of normal women. These findings suggested that hTeBG and hABP share common epitopes. We next determined whether hABP was secreted into the blood or amniotic fluid by fractionating these fluids in Con A-Sepharose columns. Unlike testicular extracts, male serum and amniotic fluid contained single immunoreactive and steroid-binding species which bound specifically to Con A. We conclude from these observations that hABP (peak I), peak II activity, and hTeBG have common immunodeterminants and that if hABP is secreted into the blood of men, then its carbohydrate chains bind to Con A, making it indistinguishable from hTeBG under these conditions.

Demonstration of heavy and light protomers of human testosterone-estradiol-binding globulin

Human testosterone-estradiol-binding globulin (hTeBG) was purified from pregnancy serum by sequential ammonium sulfate precipitation, affinity chromatography, and hydroxylapatite chromatography. An overall purification of 2800-fold was achieved with a 27% total yield. Apparent homogeneity of the final product was shown by polyacrylamide gel electrophoresis with or without sodium dodecyl sulfate (SDS). The equilibrium dissociation constant (Kd) at 4 degrees C for 5 alpha-dihydrotestosterone (DHT) was estimated to be 1.94 +/- 0.95 X 10(-9) M. Analysis of the purified protein revealed microheterogeneity with regard to size on polyacrylamide gel in the presence of SDS and to charge on isoelectric focusing gels. The apparent molecular weight of native hTeBG determined by gradient gel electrophoresis was 115,000. SDS-polyacrylamide gel electrophoresis indicated that hTeBG is comprised of two molecular weight components of 53,000 and 46,000, which are designated as heavy (hTeBGH) and light (hTeBGL) protomers, respectively. Photolysis of purified hTeBG with [1,2-3H]17 beta-hydroxy-4,6-androstadien-3-one [( 3H]delta 6-testosterone) resulted in specific labeling of its binding sites. Analysis of photolabeled products by SDS-polyacrylamide gel electrophoresis revealed two radioactive products with electrophoretic mobilities identical to those of the hTeBGH and hTeBGL. The ratio of hTeBGH to hTeBGL was about 10:1. The H and the L protomers were separated and examined by peptide mapping using protease V8 and chymotrypsin. Comparison of the fragmentation patterns produced by these proteases revealed that hTeBGH and hTeBGL components were nearly identical. Removal of sialic acid or carbohydrate residues from hTeBG did not affect the presence of two molecular components. Isoelectric focusing of native hTeBG demonstrated three isoelectric variants with pIs at 4.75, 4.85 and 4.90. After treatment with neuraminidase and other glycosidases, only two isoelectric species were observed with more alkaline pIs. Although purified hTeBG appeared heterogeneous with regard to size and charge, it was remarkably homogeneous in its ability to absorb to Concanavalin A-Sepharose. We conclude that hTeBg, like the androgen binding proteins of the rabbit and rat, is a dimer whose monomer exhibits two protomeric forms.

The hormonal and cellular control of Sertoli cell secretion

Sertoli cells synthesize and secrete a number of cell-specific products including androgen binding protein (ABP), as well as "serum proteins" such as transferrin. The secretion of these proteins is regulated by extra-testicular hormones such as FSH and insulin; Leydig cell-produced steroids and proopiomelano-cortin-derived peptides; and the presence of peritubular myoid cells and/or factors secreted by these cells. Many of the Sertoli cell proteins are secreted in a cyclic fashion during the different stages of the spermatogenic cycle suggesting communication between Sertoli cells and developing germ cells. The availability of quantitative measurements for Sertoli cell-specific proteins such as ABP make it feasible to follow Sertoli cell function in vivo by measuring these products in serum. A bidirectional secretion of proteins by Sertoli cells is proposed to explain the presence of specific peptides in the male reproductive tract and blood.

Acute fatty liver of pregnancy--survival despite associated severe preeclampsia, coma and coagulopathy

Acute fatty liver of pregnancy is the least common and most serious cause of jaundice of pregnancy. It is rare, fewer than 100 cases having been reported (Koff, 1981). There is a high probability that it is frequently misdiagnosed and categorized vaguely as some form of variant of 'toxaemia of pregnancy' which is not surprising because of its late-pregnancy onset and the production of multi-system manifestations (Holzback, 1976). In the case reported here, there was associated severe preeclampsia with fetal intrauterine death but maternal survival.

Radioimmunoassay of testosterone-estradiol-binding globulin in humans: a reassessment of normal values

Antiserum against human testosterone-estradiol-binding globulin (hTeBG) was prepared in rabbits, and its specificity was demonstrated by crossed immunoelectrophoresis. A RIA for the measurement of hTeBG in serum was developed. With this assay, hTeBG was readily measured in 1-2 microliters serum. Interassay coefficients of variation for pools of serum from men, women, and women in late pregnancy were 7.7%, 5.5%, and 6.1%, respectively. Interassay coefficients of variation for the same pools were 10%, 12%, and 12%, respectively. The TeBG levels in a number of nonselected subjected determined by the present method show good correlations with those obtained by steady state polyacrylamide gel electrophoresis and dextran-coated charcoal assay. The concentrations of TeBG determined by the RIA in sera from men, women, and women in late pregnancy were 18 +/- 9 (n = 12), 54 +/- 13 (n = 8), and 374 +/- 55 (n = 6) pmol/ml (mean +/- SD), respectively.

Partial characterization of human spermatozoal phosphodiesterase and adenylate cyclase and the effect of steroids on their activities

In sonicated human spermatozoa, phosphodiesterase hydrolyzed adenosine 3':5'-monophosphate (cAMP) at 20.80 +/- 3.23 nmoles/10(8)sperm/20 min at 37 degrees C (50 microM cAMP, initially). In human semen, about 60% of the phosphodiesterase activity was in the spermatozoa. Both polyacrylamide gel electrophoresis and DEAE-cellulose column chromatography indicated that there are at least 5 isozymes of phosphodiesterase. Various steroids were tested at a concentration of 2 micrograms/ml for their effects on phosphodiesterase activity in semen. None was found to have any significant effect. In sonicated human spermatozoa, adenylate cyclase synthesized cAMP at 0.02-2.11 nmoles/10(8)sperm/20 min at 37 degrees C (1 mM ATP, initially) depending on the availability of Mn2+ and caffeine in the assay mixture. Mn2+ was demonstrated to be a potent adenylate cyclase activator in human spermatozoa and its effect on human sperm adenylate cyclase was found to be dose-dependent. Cholera toxin, at a concentration of 20 micrograms/ml, had no effect on human sperm adenylate cyclase activity after it had been incubated with the intact spermatozoa for between 5 min and 5 h at 37 degrees C before the sperm were homogenized and the rate of cAMP formation assayed. In addition, human sperm adenylate cyclase decayed rapidly at 37 degrees C. Of various steroids tested at a concentration of 2 micrograms/ml for their effects on human sperm adenylate cyclase activity, only oestradiol-17 beta showed a significant effect, elevating the rate of cAMP formation by about 30%.

Partial purification of components from fasting human blood serum which stimulate the forward migration of human spermatozoa

Components from fasting human serum that could stimulate the forward migration of human spermatozoa were isolated by gel filtration on Sephadex G-25. The results suggest that these components may be used to enhance sperm forward migration and, hence, pregnancy rate in artificial insemination with husband's semen. (AIH) especially in cases where the sperm forward migration is not optimal.

Quantitative structure-activity relationships of aromatic esters of 1-methyl-4-piperidinol as analgesics

Substituted benzoic acid esters of 1-methyl-4-piperidinol showed analgesic activity when assayed by the mouse hot-plate methods, the more potent ones falling in the morphine-codeine range. To understand how substituents on the aromatic ring affect the analgesic potency, quantitative structure-activity correlations were carried out on a series of 44 derivatives. Among the various substituent parameters included in the study, Lortho (Length of ortho-substituents) and B1 (minimal width of substituents) or E8 at meta and para positions gave negative correlation with the potency, while lipophilicity (especially pi meta) and the ability of being a hydrogen-bond acceptor enhanced the potency. Based on the QSAR results, a substitution pattern of the phenyl group was defined for optimal activity. Implications on drug-receptor interactions and the possible binding mode of these compounds were discussed.

Effect of cAMP, Mn2+, and phosphodiesterase inhibitors on human sperm motility

The effects of cyclic adenosine monophosphate (cAMP), MnCl2, caffeine, and theophylline at concentrations of 10 mM on human sperm motility and forward migration in vitro were tested. cAMP was effective in activating human spermatozoal motility and forward migration after incubation with the spermatozoa for 3 hr or more and 5 hr, respectively, whereas caffeine and theophylline were effective in activating sperm motility after incubation with the spermatozoa for 1 hr or more. Caffeine and theophylline significantly activated sperm forward migration only after incubation with the sperm for 5 hr. MnCl2, a potent sperm adenylate cyclase activator, had no significant effect in improving human sperm motility and forward migration.

Effects of steroids on the in vitro forward migration of human spermatozoa

The effects of 14 steroids at concentrations between 0.1 and 10 micrograms/ml on human spermatozoal forward migration in vitro were tested. Oestradiol-17 beta at a concentration of 0.1 microgram/ml significantly activated spermatozoal forward migration in ejaculated human semen. However, the effect of oestradiol-17 beta at concentrations of 2 and 10 micrograms/ml on ejaculated human sperm motility was not significantly different from the control where no steroid was added. Progesterone, testosterone, oestriol, oestrone, oestradiol-17d, and ethinyl oestradiol significantly inhibited human spermatozoal forward migration at concentrations of 10 micrograms/ml. Chlormadinone acetate and medroxyprogesterone acetate at concentrations of 2 and 10 micrograms/ml significantly inhibited human spermatozoal forward migration, while norethynodrel, ethynodiol diacetate, norgestrel and lynoestrenol significantly inhibited human spermatozoal forward migration at concentrations between 0.1 and 10 micrograms/ml. However, norethindrone had no demonstrable effect on human spermatozoal forward migration at the above concentrations.

The binding of oestradiol-17beta to human spermatozoa - an electron microscope autoradiographic study

The location of steroid binding sites with specificity for oestradiol-17beta at an ultrastructural level has been examined on human spermatozoa by electron microscope autoradiography. About 75% of the 438 gains produced by 3H-oestradiol-17beta, and counted on electron microscope autoradiographs, were found over the plasma membrane or within 1000 A of it. This study provides evidence suggesting that the plasma membrane is a site of action of oestradiol-17beta in human spermatozoa.

The binding of sex steroids to human spermatozoa. An autoradiographic study

The locations of steroid binding sites with specificities for 17 beta-oestradiol, progesterone and testosterone have been examined on human spermatozoa by autoradiography. The binding sites were not evenly distributed over the entire surface of human spermatozoa. They were more densely located on the midpiece of the tail, less on the head and neck, and least on the principal- and end pieces of the tail. The binding sites for 17 beta-oestradiol were specific, with 3H-17 beta-oestradiol being displayed by unlabelled 17 beta-oestradiol, but less readily displaced by either progesterone or testosterone. The binding sites for testosterone were less specific than those for 17 beta-oestradiol or those for progesterone. Both 17 beta-oestradiol and progesterone were good competitors for testosterone binding sites, while the binding of 3H-progesterone was easily displaced by 17 beta-oestradiol, but less readily displayed by testosterone. Since there was preferential binding of these steroids to the mid-piece, and strong competition for binding between 17 beta-oestradiol and progesterone, these studies appear to provide information on the sites of action for the reported effects of these and related steroids on spermatozoal motility, migration and metabolism.

Mitogenic activity and plasminogen activator in harvest fluid concentrates from mammary cells in culture

Harvest fluid concentrates (HFC's) from three human mammary tumor cell lines (T47D), HSO578T, and MDA-MB-157), one nontumorigenic human mammary cell line (HBL-100), and one mouse mammary tumor cell line (MCG-T14) stimulated thymidine incorporation in confluent quiescent BALB/c 3T3 cells in a dose-dependent manner. HFC's from all of the cell lines also exhibited plasminogen activator activity. Levels of mitogenic activity and plasminogen activator in the HFC preparations were not correlated with cell growth potential or with the amount of protein which was recovered in the HFC's. High levels of mitogenic activity and plasminogen activator in the HFC's from HBL-100 cells suggested that the production of these biological activities is not a unique feature of tumorigenic mammary cells. The HFC's from three human cell lines (T47D), HS0578T, MDA-MB-157) exhibited high levels of mitogenic activity but low levels of plasminogen activator. This suggested that plasminogen activator is not the source of the mitogenic activity in the HFC's from these cells. The HFC's from a human mammary carcinoma line, BT-20, contained very low levels of mitogenic activity and plasminogen activator. In addition, BT-20 HFC's inhibited the mitogenic activity of fetal bovine serum in a dose-dependent manner. It is proposed that BT-20 cells are the source of a macromolecular inhibitor of serum mitogens.

Activation of spermatozoal forward migration in vitro by hydrocortisone

The effects of hydrocortisone and cortisone on spermatozoal motility in vitro were tested Hydrocortisone at concentrations of 50, 100 and 1000 nmoles/ml was effective in activating in vitro the forward migration and the motility of boar spermatozoa recovered from the cauda epididymidis. Where boar epididymal spermatozoa were incubated with hydrocortisone at concentrations of 50, 100 and 1000 nmoles/ml for between 0 and 24 h at 25 degrees C in vitro, the spermatozoal motility was significantly higher than where no hydrocortisone was added. With ejaculated boar spermatozoa, hydrocortisone at concentrations of 100 and 1000 nmoles/ml increased the spermatozoal motility for between 0 and 2 h and at concentration of 50 nmoles/ml increased spermatozoal motility for between 2 and 24 hr at 25 degrees C in vitro. After 4 incubation, the effect of hydrocortisone at a concentration of 100 nmoles/ml on boar ejaculated sperm motility was not significantly different from the control. But, hydrocortisone at a concentration of 1000 nmoles/ml inhibited for forward migration of boar ejaculated sperm after it had been incubated with the sperm for 6 h. Cortisone, although structurally similar to hydrocortisone, had no significant effect in improving the motility of boar spermatozoa. Both hydrocortisone and cortisone had no demonstrable effect on the forward migration and the motility of human spermatozoa in vitro.

The effect of steroids on the in vitro migration of washed human spermatozoa in modified Tyrode's solution or in fasting human blood serum

In modified Tyrode's solution, 17 beta-estradiol at concentrations between 0.1 microgram/ml and 320 nmoles/ml was effective in increasing human spermatozoal forward migration. 17 alpha-Estradiol, although structurally similar to 17 beta-estradiol, had no effect on human spermatozoal motility. DL-Norgestrel at concentrations between 0.1 migrogram/ml and 320 nmoles/ml inhibited spermatozoal motility. These stimulatory and inhibitory effects were not observed when fasting human blood serum was used as a penetration medium in place of the modified Tyrode's solution. Also, the motility of spermatozoa suspended in fasting human blood serum was better than that of spermatozoa suspended in modified Tyrode's solution or in seminal plasma. These observations indicated that there is a component(s) of fasting human blood serum which increases spermatozoal motility and can counteract the activation or inhibition of spermatozoal motility by 17 beta-estradiol or DL-norgestrel at the concentrations used here.

Isolation and characterization of mutations in the structural gene for protease III (ptr)

Escherichia coli mutants defective in protease III were isolated by enzyme assays of heavily mutagenized colones. One mutant produced thermolabile enzyme, and it is presumed to have a mutation in the structural gene of protease III. Two other mutants mapping at the same site had less than 5% of the wild-type protease III level. The genetic locus of these mutations, designated ptr, was located at approximately 60 min on the E. coli linkage map based on its high frequency (70%) of contransduction by P1 with argA. Strains with less than 5% of the wild-type protease III activity grew normally and degraded nonsense fragments of beta-galactosidase at wild-type rates.