Effect of prolactin on the calcium binding and/or transport of ejaculated and epididymal human spermatozoa

The prolactin concentration in human seminal plasma and in human epididymal cauda fluid was assessed by radioimmunoassay. The prolactin concentration in cauda plasma was found to be similar to that found in male blood serum (5.5 to 9.1 ng/ml) and significantly lower than the concentration of the hormone found in seminal plasma obtained either from euspermic (48 +/- 12 ng/ml) or from vasectomized volunteers (50 +/- 10.2 ng/ml) (P less than 0.001). Calcium binding and/or transport in ejaculated spermatozoa were found to be little (0.29 +/- 0.08 nmoles/10(8) cells) and dependent on a quickly saturable process. The addition of 200 ng of human prolactin/ml induced a 60% increase in this parameter, while 50 ng of prolactin/ml were ineffective. Epididymal human spermatozoa differ from ejaculated sperm cells in showing greater, time-dependent, calcium binding and/or transport under basal conditions (2.00 +/- 0.35 nmoles/10(8) cells/hour), and in being more susceptible to the stimulating action of prolactin (4.4 +/- 0.68 nmoles/10(8) cells/hour in the presence of 50 ng of prolactin/ml).

Effect of orciprenaline on hypoxic pulmonary vasoconstriction in dogs

The effect of orciprenaline on hypoxic pulmonary vasoconstriction and arterial oxygen tension (PaO2) was studied in 8 dogs by measuring the redistribution of blood flow in response to unilateral alveolar hypoxia. The distribution of blood flow was recorded continuously by measuring the radioactivity of the mixed expired gas from each lung during the continuous intravenous infusion of xenon-133. The hypoxic vasoconstrictor response was significantly depressed by an infusion of 1.0 micrograms/kg/min of orciprenaline but not by a dose of 0.1 micrograms/kg/min. PaO2 during unilateral hypoxia was significantly lower during the infusion of the high dose of orciprenaline than it was in the control periods before or after the infusion. A bolus dose of 0.5 mg significantly increased blood flow to a lung with established hypoxic vasoconstriction and also caused a significant reduction in PaO2. Since these effects were produced in the absence of airway pressure or pulmonary vascular pressure changes, it is concluded that orciprenaline may depress the hypoxic pulmonary vasoconstrictor response in dogs.

Calcium ion requirement for rabbit spermatozoal capacitation and enhancement of fertilizing ability by ionophore A23187 and cyclic adenosine 3':5'-monophosphate

The presence of extracellular calcium is required for the in vitro occurrence of rabbit spermatozoal capacitation. However, calcium itself was found to be an inefficient agent for capacitating rabbit spermatozoa (following insemination with spermatozoa incubated for 10 hours in the presence of 2.5 X 10(-3) M calcium, only 9% of the ova cleaved). The addition of the divalent ionophore A23187 induced the early occurrence of capacitation and increased the percentage of full capacitated spermatozoa in a concentration-dependent manner (i.e, following insemination with spermatozoa incubated for 4 hours in the presence of 2.5 X 10(-3) M calcium and 2 X 10(-5) M A23187, 44% of the ova cleaved). Physiologic levels of capacitation were attained as estimated by the high proportion of ova that cleaved following in vitro insemination, when dibutyryl cyclic adenosine 3':5'-monophosphate (10(-6) m) was added in the presence of calcium (2.5 X 10(-3) M) and A23187 (2 X 10(-5) M) for treatment of spermatozoa.

Amino acid and protein concentrations of human follicular fluid

The amino acid and protein composition of human follicular fluid, obtained during surgery from women with polycystic ovaries, and of a simultaneously obtained sample of blood plasma were studied. In general, amino acid concentrations were higher in follicular fluid than in blood plasma: only the concentration of Cys was significantly lower in follicular fluid than in plasma, while Asp, Thr, Glu, Glu-NH2, Gly, Ala, and Met showed concentrations that were not significantly different in either biologic fluid. The concentration of basic amino acids, taken as group, was almost twice as high in follicular fluid as in plasma. The total protein concentration in follicular fluid was not significantly different from that in blood plasma. However, the follicular fluid albumin concentration was higher and globulin concentration lower than the respective concentrations in plasma. Polyacrylamide gel disc electrophoresis of follicular fluid showed some consistent differences, particularly in the alpha-globulin region, with the pattern observed in blood plasma. These findings are discussed in relation to the possible role of follicular fluid in capacitation and egg segmentation.

Participation of membrane sulfhydryl groups in the epididymal maturation of human and rabbit spermatozoa

Changes in the concentration of -SH groups on the human and rabbit spermatozoal membrane and during epididymal maturation were studied by means of a new fluorescent probe, carboxyphenylmaleimide (CPhM), which reacts specifically with -SH groups. Binding of CPhM did not modify oxygen uptake, motility, or viability of the sperm cells used, but produced a characteristic increase in fluorescence. By analysis of this increase it was possible to calculate the presence of 35 +/- 4.2 and 55 +/- 8 nmoles of exposed -SH groups/10(8) rabbit and human ejaculated spermatozoa, respectively. Caput epididymal cells bound significantly more CPhM than did cauda epididymal cells or ejaculated spermatozoa (155 +/- 22, 78 +/- 11, and 35 +/- 4.2 nmoles/10(8) cells, respectively, in rabbit cells; and 184, 110 +/- 18, and 55 +/- 8 nmoles/10(8) cells, respectively, in humans cells). In addition to the differences in number of exposed -SH groups observed between human and rabbit sperm cells, the behavior of these membrane-reactive groups when ethylenediaminetetraacetate and/or zinc were added to the incubation media indicates that the participation of membrane--SH groups in sperm physiology is species-specific.

Partial purification and identification of a reversible decapacitation factor from rabbit seminal plasma

Efforts have been directed toward partial purification and identification of a reversible decapacitation factor from rabbit seminal plasma. Five fractions were consistently obtained following fractionation of rabbit seminal plasma on a Sephadex G-200 column. Only the first two fractions had decapacitation factor (DF) activity. On SDS polyacrylamide gel electrophoresis, several carbohydrate-and protein-containing components were found in each fraction from the Sephadex column. Further, DF activity could be obtained in the precipitate resulting from cetyl pyridinium chloride (CPC) treatment of the active fractions from the Sephadex G-200 column. In the comparison of the components observed with SDS gel electrophoresis throughout these fractionation procedures, the reversible decapacitation activity appeared to be associated with a component containing protein and carbohydrate. From these studies, then, reversible decapacitation activity of rabbit seminal plasma appears to be associated with a glycoprotein of an approximate molecular weight of 115,000.