Evidence of mucin M1 antigens in seminal plasma and normal cells of human prostatic urethra in relation to embryonic development and tumors.

By employing immunoperoxidase methodology, using monoclonal antibodies against the peptide core of gastric mucins (M1 antigens), we demonstrate the presence of M1 mucin-producing cells that are associated with the prostatic urethral epithelium and located mainly in the veru montanum area near the prostatic ductal and utriculus junctions. The significance of these M1 cells is not yet clear. Using an immunoradiometric assay, these M1 mucins were found predominantly in the prostatic fraction obtained from seminal plasma. By chromatography on Sepharose 6B and 2B and cesium chloride gradient centrifugation, we demonstrate that high-molecular-weight components (greater than 10(7) Da) show a density of 1.45 g/ml, similar to mucins, and are immunochemically related to peptidic gastric M1 mucins. The particular location of these M1 antigens in prostatic adult urethra and their fetal expression in cloacal structures suggest that, in males, the prostatic urethral epithelium includes some remnant cells from the enteric cloaca. Finally, the presence of mucin-containing cells in the prostatic urethra could possibly explain the histogenesis of the rare benign villous tumors and primary mucinous adenocarcinomas arising from the prostatic urethral epithelium.

[Histochemical study of external urethral sphincter in the rabbit. Analysis with construction of histograms].

Male rabbit's external urethral sphincter was examined by histochemical muscle fiber typing (myosin ATP-ase staining), and the analysis with construction of histograms regarding to muscle fiber types were performed. Rabbit's external urethral sphincter was predominantly composed of fast twitch (type 2) fibers (87.3%) as a whole. But the proportion of constituent fiber types varied according to the layers, i.e., the slow twitch (type 1) fibers constituted a relatively high percentage (33.4%) in the inner third layer, while few of the type 1 fibers were found in the outer third layer. The all histograms regarding to fiber type in different layers were normal bell-shaped distribution curves. The mena diameter of type 2 fibers (14.7 microns) was evidently larger than that of type 1 fibers (20.5 microns). All three kinds of muscle fibers equally tended to increase in size toward the outer direction, and in every three layers, the diameter of type 2 was larger than that of type 1 also. The definite differences in the proportion of fiber types and fiber sizes between layers may implicate that the inner and outer layers play different roles, i.e., continuous tonic constriction in the former and sporadic strong constriction of short duration in the latter, under different neural regulations. As far as rabbit's external urethral sphincter is concerned, sporadic strong constriction should be mainly dependent on the muscle fibers of large size composing the outer layer, especially the fast twitch fibers. It is possible that the rabbit is so adapted that it could interrupt urination promptly.

[Experimental studies on urinary incontinence. II. Function and distribution of alpha 1- and alpha 2-adrenoceptors in male and female rabbit urethral smooth muscle].

The effects of various alpha-adrenergic agonists and antagonists on the contractile properties of the isolated urethra of male and female rabbits were examined and the population of alpha 1- and alpha 2-adrenoceptors, using radioligand receptor binding techniques, was also quantified to define the functional role of postsynaptic alpha-adrenoceptors in urethral smooth muscle. Norepinephrine, epinephrine (non-specific alpha-adrenergic agonists) and phenylephrine (alpha 1-adrenergic agonists) induced increases in contractile force in both the male and female urethra. Clonidine (alpha 2-adrenergic agonist) caused a relatively large contractile response in the female urethra but only a small contractile response in the male urethra. Receptor binding studies indicated that the male urethra contains almost equal amounts of alpha 1- and alpha 2-adrenoceptors (32 vs. 34 fmol/mg protein, respectively) whereas the female urethra contains a significantly greater density of alpha 2- than alpha 1-adrenoceptors (122 vs. 34 fmol/mg protein, respectively). Our studies have indicated that: (1) both alpha 1-and alpha 2-adrenoceptors cause contractile responses in male and female rabbit urethra; (2) the greater response to alpha 2-agonist in female than male urethra is correlated with a higher density of alpha 2-adrenoceptors in this tissue.

Spinal cord lesions at different levels affect either the adrenergic or vasoactive intestinal polypeptide-immunoreactive nerves in the human urethra.

The urethras from 1 patient with cervical (C1-2) and 2 patients with thoracic (T10) spinal cord lesions were studied histochemically and immunohistochemically for adrenergic and vasoactive intestinal polypeptide-immunoreactive nerves. Dense vasoactive intestinal polypeptide-immunoreactive but not adrenergic nerves were found in the urethral smooth muscle, around the blood vessels and at the base of the mucosa in the patients with thoracic lesions. In contrast, adrenergic but not vasoactive intestinal polypeptide-immunoreactive nerves were found associated with the smooth muscle of the urethra and around the blood vessels in the patient with a cervical lesion. In patients with cervical or thoracic lesions neither adrenergic nor vasoactive intestinal polypeptide-immunoreactive nerves were found around striated muscle fibers of the intrinsic external urethral sphincter. The results are discussed in relation to the possible function of these nerves in the urethra of patients with autonomic dysreflexia and detrusor-sphincter dyssynergia.

Intersex mice composed of androgen insensitive Tfm and wild-type cells analysed by 3H dihydrotestosterone autoradiography.

The X-linked testicular feminization mutation (Tfm) in the mouse is characterized by an androgen receptor defect. Due to random X-chromosome inactivation, XTfm/X+ heterozygotes are mosaics with respect to Tfm. They are composed of androgen receptor deficient XTfm cells and normal X+ wild-type cells. If Tfm heterozygotes are converted to XX males by the sex reversal factor (Sxr) the mosaicism is expressed. Therefore in sex reversed Tfm heterozygotes (XTfm/X+-Sxr) intersexual sex organs develop. In five intersexes with small male accessory glands and hypospadia and one heavily feminized intersex with vagina and caudally dislocated deferent ducts the mosaic is visualized by 3H-DHT-autoradiography. In the epididymis differentiated wild-type cells show nuclear labeling, whereas undifferentiated Tfm cells are unlabeled. Unlabeled Tfm cells are also encountered in the vesicular glands of the heavily feminized animal, demonstrating that Tfm cells can participate in the formation of male sex glands. The urethral glands of the mosaic animals are composed of unlabeled Tfm lobules exhibiting the female phenotype of the glands, and of labeled wild-type lobules exhibiting the male phenotype. Formation of a vagina and deviation of the deferent ducts is correlated with lack of androgen binding sites in the connective tissue.

Progesterone receptors in the female lower urinary tract.

When female estrogenized rabbits were injected i.v. with 3H-progesterone, the tritium concentration determined after one hour was about two to three times higher in urethra, urinary bladder and vagina than in the heart. High affinity progesterone receptors (KD = 1-2 nM) could be demonstrated in both cytoplasmic and nuclear fractions prepared from estrogenized rabbit urethra, bladder and vagina. The cytosolic receptor concentration in both urethra and bladder was about half of that in the vagina. The concentration of nuclear receptors in urethra was not significantly different from that in the vagina, but in the bladder the concentration was only about one fourth of that in the vagina or urethra. The mean KD of cytosolic receptors from bladder was significantly higher than the corresponding values in urethra and vagina. Progesterone binding sites in the bladder had a broader hormonal specificity than those in the urethra or vagina. The present demonstration of specific progesterone receptors in the female urethra might provide a possible link between estrogen progesterone interaction and the appearance of urinary incontinence during pregnancy in women.

Vasoactive intestinal polypeptide concentration in human bladder neck smooth muscle and its influence on urodynamic parameters.

Three human studies were performed to evaluate the influence of vasoactive intestinal polypeptide (VIP) on bladder and urethral function. Bladder neck smooth muscle biopsies were obtained from nine men with functional bladder neck obstruction, from 10 men with medium sized benign prostatic hypertrophy and from four patients with a normal infravesical outlet. The biopsies were analysed for VIP by radioimmunoassay and by immunohistochemistry. No differences were found between the groups. Pressure-flow-EMG studies were performed in five men and urethrocystometry was performed in six women at rest, repeated coughing and at squeezing before, during and after VIP 3 micrograms/kg X h intravenously. No systematic changes developed in any of the urodynamic parameters.

Sex differences in function and distribution of alpha 1- and alpha 2-adrenoceptors in rabbit urethra.

To define the functional role of postsynaptic alpha-adrenoceptors in urethral smooth muscle, we examined the effects of various alpha-adrenergic agonists and antagonists on the contractile properties of the isolated urethra of male and female rabbits and quantified the population of alpha 1-and alpha 2-adrenoceptors, using radioligand receptor binding techniques. Norepinephrine (NE), epinephrine, and phenylephrine, an alpha 1-adrenergic agonist, induced increases in contractile force in both the male and female urethra. Clonidine, an alpha 2-adrenergic agonist, caused a relatively large contractile response in the female urethra but only a small contractile response in the male urethra. Receptor binding studies indicated that the male urethra contains almost equal amounts of alpha 1- and alpha 2-adrenoceptors (32 vs. 34 fmol/mg, respectively), whereas the female urethra contains a significantly greater density of alpha 2- than alpha 1-adrenoceptors (122 vs. 34 fmol/mg, respectively). Our studies indicate that both alpha 1- and alpha 2-adrenoceptors cause contractile responses in male and female rabbit urethra; and the greater response to alpha 2-agonist in female than male urethra is correlated with a higher density of alpha 2-adrenoceptors in this tissue.

Noradrenaline content in canine lower urinary tract tissue.

To examine the distribution of sympathetic nerve fibers in the lower urinary tract, the noradrenaline content was measured in the urinary bladder dome and base, and proximal and distal urethra of the male and female dogs, using high pressure liquid chromatography-electrochemical detection (HPLC-ED). The noradrenaline content was the highest in the proximal urethra and the lowest in the urinary bladder dome in both sexes. The noradrenaline content of the proximal urethra was significantly higher in the male than in the female, whereas the content of the urinary bladder base and the distal urethra was lower in the male than in the female. These data suggest that sympathetic innervation is the richest in the proximal urethra in the lower urinary tract and that there is a sex difference in the sympathetic innervation in the lower urinary tract.

The fiber type of the rabbits' striated external urethral sphincter: electrophoretic analysis of myosin.

The fiber type of the rabbits' external urethral sphincter was investigated with O'Farrell's 2-dimensional electrophoresis of constituent proteins of glycerinated muscle, peptide mapping of myosin heavy chains and non-denaturing pyrophosphate gel electrophoresis of myosin. It was determined as fast type by all three methods. The relative proportions of muscle fibers which were estimated from myosin light chain contents were 88 per cent fast type and 12 per cent slow type. On the basis of the results presented, it was shown to be fast twitch muscle, but not identical to the psoas muscle.

Effects of urinary bladder distention on location of the urinary bladder and urethra of healthy dogs and cats.

Evaluation of the anatomic location of the distended and empty urinary bladders and urethras of healthy adult male and female dogs and cats by retrograde urethrocystography revealed substantial variations. In 15 dogs in lateral recumbency with empty bladder lumens, the caudal portion of the urinary bladder was within the pelvic canal in 5 of 7 male and 5 of 8 female dogs. In female dogs examined in ventrodorsal recumbency, only 4 of 8 had the empty urinary bladders in part within the pelvic canal. After luminal distention, 3 of 7 male and 3 of 8 female dogs, while in lateral recumbency, had the urinary bladders in part intrapelvically. However, when female dogs were placed in ventrodorsal recumbency, only 1 of 7 urinary bladders was in part within the pelvis. The urinary bladders of 14 cats were consistently within the abdominal cavity, irrespective of whether the bladder lumen was distended or empty. Urethral flexures occurred in dogs with intrapelvic bladders that were distended or empty. Urethral flexures were not found in cats. The urethras of dogs and cats in lateral recumbency were generally closer to the floor of the pelvis after urinary bladder distention than when the bladder was empty. The urethra of the dogs and cats in ventrodorsal recumbency was to the left or right of or on the midsagittal plane, whether the urinary bladder was empty or distended. A greater degree of lateral displacement was encountered in ventrodorsal recumbency after urinary bladder distention.

Immunoreactive prolactin in mouse urethral glands.

Immunoreactive prolactin was demonstrated in the acinar cells of urethral glands in some inbred strains of mice by immunoperoxidase technique. The significance of the presence of prolactin or its related substances in the urethral glands in relation to their role in the urinary tract is discussed.

Immunohistochemical distribution of S-100 antigen in the urinary system of man and rat.

The immunohistochemical distribution of S-100, a protein originally isolated from the brain, has been investigated at the light and electron microscopic levels in rat and man urinary systems. In both species the antigen essentially exhibited the same location, restricted, with different degrees of staining, to certain cells in the kidney, i.e. collecting tubules, thin limbs of Henle's loop and renal papillae.

Electrophoretic and ultrastructural analysis of the rabbit's striated external urethral sphincter.

The male rabbit's external urethral sphincter was investigated with O'Farrell's 2-dimensional electrophoretic analysis of myosin light chains and electron microscopy. Its pattern of myosin light chains was different from that of the soleus (predominantly slow twitch muscle) but was very similar to that of the psoas (predominantly fast twitch muscle). Ultrastructurally it was shown to be red muscle resembling the soleus. Therefore the fiber type of the rabbit's external urethral sphincter was determined to be the red (fast) type.

Effects of estradiol on norepinephrine-induced contraction, alpha adrenoceptor number and norepinephrine content in the female rabbit urethra.

Several studies have revealed that estrogen treatment increases the reactivity to catecholamines of various tissues. In the present study it was found that estrogen treatment caused an increased sensitivity to norepinephrine (NE) of the isolated female rabbit urethra. There was a 3-fold shift to the left of the concentration-response curve for longitudinal tension in perfused urethras and for tension in urethral ring preparations. Possible mechanisms for this increase in sensitivity were investigated by studying radioligand binding to the alpha adrenoceptors and by measuring the NE content of the urethras. Using [3H]dihydro-alpha-ergocryptine as a marker for alpha adrenoceptors, a more than 2-fold increase in the receptor number was found after estrogen treatment. This is suggested to be attributable to a selective increase in the number of alpha-2 adrenoceptors. No significant change was found in the affinity of [3H]dihydro-alpha-ergocryptine to the receptor. The total NE content in the urethra was not changed by estrogen treatment. However, if calculated per milligram of wet weight, the NE content was reduced to half in estrogen treated animals. It is suggested that in the rabbit urethra the estrogen-induced increased sensitivity to the contractant effects of NE, at least in part, is attributable to an increase in the number of postjunctional alpha-2 adrenoceptors.