Immunochemical detection, physicochemical characterization and levels of pregnancy-associated endometrial alpha 2-globulin (alpha 2-PEG) in seminal plasma of men

Pregnancy-associated endometrial alpha 2-globulin (alpha 2-PEG), the major secretory protein of the human uterine endometrium during the luteal phase of the menstrual cycle and early first trimester of pregnancy, has been detected by immunochemical techniques in seminal plasma. Biochemical analysis and immunoblotting has verified that immunoreactive alpha 2-PEG in seminal plasma exhibits properties identical to those of endometrial alpha 2-PEG, i.e. Concanavalin A-binding dimeric glycoprotein of native Mr 56,000, subunit Mr 28,000, average pI 4.7 and of alpha 2-mobility. Concentration of alpha 2-PEG in seminal plasma was 22.13 +/- 2.82 micrograms/ml (mean +/- s.e.m., n = 110) which compared to 12.02 +/- 1.65 micrograms/ml (mean +/- s.e.m., n = 48) found in amniotic fluid at 11-20 weeks of pregnancy, to 4.29 +/- 1.66 micrograms/ml (mean +/- s.e.m., n = 15) in uterine luminal fluid in women during the luteal phase and to 0.245 +/- 0.025 micrograms/ml (mean +/- s.e.m., n = 10) in sera at 10 weeks of pregnancy. This distribution is very different from that observed for pregnancy-associated placentally-derived serum proteins detected in seminal plasma. The source of alpha 2-PEG in seminal plasma is unknown but is unlikely to be the testis because of the normal levels observed in vasectomized men. In the endometrium alpha 2-PEG synthesis and secretion appears to be related to progesterone-dependent differentiation of the glandular epithelium. Therefore these observations suggest that a different mechanism of regulation of the gene for alpha 2-PEG operates in the male reproductive tract.

Plasma 1,25(OH)2D3 response to parathyroid hormone, cyclic adenosine monophosphate, and phosphorus depletion in the spontaneously hypertensive rat

Spontaneously hypertensive rats (SHR) have several abnormalities of calcium metabolism compared with normotensive control Wistar-Kyoto (WKY) rats. Previously the vitamin D metabolite 1,25-dihydroxycholecalciferol (1,25[OH]2D3) was found to be inappropriately low in SHR in view of their ionized hypocalcemia and hyperparathyroidism. We examined the responses of plasma 1,25(OH)2D3 to several known stimuli. Baseline plasma 1,25(OH)2D3 levels tended to be lower in SHR than WKY rats (51.5 +/- 4.3 vs. 82.3 +/- 14.1 pg/ml, P = 0.06). Infusion of a pharmacologic dose of parathyroid hormone (8 U/hr over a period of 17 hours) resulted in a plasma 1,25(OH)2D3 level of 504 +/- 77 pg/ml in SHR vs. 1016 +/- 211 pg/ml in WKY rats (P less than 0.03). Cyclic adenosine monophosphate infusion (1 mumol/hr/100 gm over a period of 17 hours) in thyroparathyroidectomized animals resulted in a 1,25(OH)2D3 level of 121 +/- 24 pg/ml in SHR vs. 557 +/- 26 pg/ml in WKY rats (P less than 0.01). After dietary phosphorus depletion for 3 weeks, SHR also had lower 1,25(OH)2D3 levels than WKY rats (83 +/- 13 vs. 300 +/- 42 pg/ml, P less than 0.001) even though a comparable degree of hypophosphatemia was achieved. Thus, the response of plasma 1,25(OH)2D3 levels to several known stimuli is submaximal in SHR as compared with WKY rats, suggesting defective synthesis or enhanced metabolic clearance of this hormone.

Amniotic fluid concentrations of secreted pregnancy-associated endometrial alpha 1- and alpha 2-globulins (alpha 1- and alpha 2-PEG)

The levels of pregnancy-associated endometrial alpha 1- and alpha 2-globulins (alpha 1- and alpha 2-PEG), the two major proteins synthesized and secreted by the endometrium in vitro, have been assayed in 210 amniotic fluid specimens obtained at termination of pregnancy or by amniocentesis, or at delivery. alpha 1-PEG was undetectable until week 10 and thereafter rose to peak levels between weeks 20 and 24. Levels fell 15-fold by week 35 but substantial amounts were still present at parturition. alpha 2-PEG was present at highest levels during early pregnancy, at weeks 6-15, but thereafter levels rapidly fell until during weeks 31-42 alpha 2-PEG was detectable in only 3 of 25 specimens. During weeks 15-20, when alpha 2-PEG levels fell and alpha 1-PEG levels rose, a high correlation was observed between the week of gestation and the log of the ratios of the concentration of these proteins. These observations provide the opportunity to assess the role of endometrial and decidual dysfunction in the aetiology of pregnancy disorders.

Protein synthesis and secretion by the human endometrium during the menstrual cycle and the effect of progesterone in vitro

To identify markers of endometrial differentiation specimens of endometrium from the menstrual cycle were incubated in vitro with [35S]methionine, in the absence or presence of progesterone, and protein synthesis and secretion were studied by fluorographic analysis of one dimensional SDS/gradient polyacrylamide gels. Changes were demonstrated in the rate of synthesis and secretion of a number of endometrial proteins (EP) during the cycle and in response to progesterone. Endometrial proteins were classified into three groups: Group I-synthesized and secreted throughout the menstrual cycle and unaffected by progesterone exposure; Group II-synthesis and secretion associated with histological type of endometrium and unaffected by progesterone exposure, e.g. EP 13 (Mr 33,000) with proliferative, EP 15 (Mr 28,000) with secretory and EP 14 (Mr 32,000) with late secretory endometrium; Group III-synthesis and secretion regulated by progesterone exposure irrespective of source of endometrium, e.g. EP 9 (Mr 54,000) and 11 (Mr 45,000). The Group II proteins EP 14 and 15 were also the major secretory protein products of endometrium from first and second trimester pregnancy respectively, the native forms referred to as pregnancy-associated endometrial alpha 1- and alpha 2-globulins (alpha 1- and alpha 2-PEG). We conclude that EP 15 (alpha 2-PEG) represents a human analogue of uteroglobin.

Investigation of the mechanism of decreased sensitivity of the rat seminal vesicle to norepinephrine by lithium

Li+ is reported to reduce sensitivity of alpha-adrenergic receptors to NE. The present investigation was designed to investigate the mechanism of this decreased sensitivity on the rat isolated seminal vesicle. In innervated preparations, 1.35 X 10(-3) M Li+ (i) shifted the concentration-response curves of NE, methoxamine, ACh and BaCl2 to the right and reduced their maximum responses; (ii) antagonized the leftward shift and the enhancement of maximum responses to NE by cocaine (2.9 X 10(-4) M), and (iii) reduced only the maximum responses to KCl. In denervated preparations, 1.35 X 10 (-3) M Li+ shifted the concentration response curve of NE to the left without any change in the maximum responses. The antagonistic effects of Li+ on maximal responses to NE, ACh and KCl observed in innervated preparations were significantly increased in Ca++-free medium. Li+ (1.35 X 10(-3) M) increased NE uptake by the seminal vesicle significantly. It is concluded that decreased sensitivity of the seminal vesicle to NE by Li+ could be due to an increase in the uptake of NE and to a nonspecific postsynaptic spasmolytic action.

Simplified radioimmunoassay for triiodothyronine: evaluation of a new commercial kit

A new triiodothyronine (T3) radioimmunoassay kit offers simplicity of method, short incubation time, specificity, and reproducibility. 125I-labeled T3 and unknown serum (or standard) are added to alkaline buffered (pH 12.4) Sephadex G-25 columns; the T3 is freed of proteins with an alkaline buffer wash, antiserum is added, and the columns are incubated at room temperature for 2 h. "Free" hormone (i.e., unbound to antiserum) remains on the column after a second wash. The radioactivity on the column is counted and related to the total activity added. The T3 standards produced a straight line on log-logit plot; reactivity of analytical-grade thyroxine was 0.6% on weight basis; and the analytical recovery of T3 added to a T3-free serum was complete. Euthroid, hyperthyroid, and hypothyroid ranges were 0.74-2.64, 2.91-7.52, and 0-1.21 mug/liter, respectively. These values correlated well with both the clinical status of patients and with values obtained by an established radioimmunoassay method. The procedure is simply done; results may be obtained in less than 4 h.

Simplified radioimmunoassay for triiodothyronine: evaluation of a new commercial kit

A new triiodothyronine (T3) radioimmunoassay kit offers simplicity of method, short incubation time, specificity, and reproducibility. 125I-labeled T3 and unknown serum (or standard) are added to alkaline buffered (pH 12.4) Sephadex G-25 columns; the T3 is freed of proteins with an alkaline buffer wash, antiserum is added, and the columns are incubated at room temperature for 2 h. "Free" hormone (i.e., unbound to antiserum) remains on the column after a second wash. The radioactivity on the column is counted and related to the total activity added. The T3 standards produced a straight line on log-logit plot; reactivity of analytical-grade thyroxine was 0.6% on weight basis; and the analytical recovery of T3 added to a T3-free serum was complete. Euthroid, hyperthyroid, and hypothyroid ranges were 0.74-2.64, 2.91-7.52, and 0-1.21 mug/liter, respectively. These values correlated well with both the clinical status of patients and with values obtained by an established radioimmunoassay method. The procedure is simply done; results may be obtained in less than 4 h.