Epididymal mitochondrial status of hypothyroid rats examined by transmission electron microscopy.

Hypothyroid rats show alterations in the mobility of sperm recovered from their epididymides. The AgNOR technique, immunohistochemistry and transmission electron microscopy were used to investigate changes in epithelial cells from epididymides of rats treated with (131)I. Counting of NORs did not permit detection of changes in the proliferative capacity of epididymides of hypothyroid animals. Transmission electron microscopy revealed changes in the mitochondria of hypothyroid rats that probably are associated with incipient apoptosis.

Epididymal cytology changes in hypothyroid rats.

The purpose of this research was to investigate, using light, transmission, and scanning electron microscope, the effect of hypothyroidism on the ultrastructure of the rat epididymis. Thyroidectomy was obtained by ip injection of 270 microCi of (131)I per rat. One month later, several portions of cauda epididymis were examined. Morphological differences were detected in the epididymis of the hypothyroid animals when compared to the control normal rats. The hypothyroid conditions were associated with important changes in the epididymis. The light observations showed cells with clearing of the chromatin and increased density and thickness of the chromatic rim, chromatinic net, and disappearance of the segment of the chromatin rim. In the scanning electron microscope broken, oblique, denuded epithelial cells with loss of stereocilia were observed, as well as flattening of the tubule. The hypothyroid condition under transmission electron microscope was associated with a decrease in the height of the cells, diminution of the internal lumen and number of mitoses, and decreased chromatin decondensation. Results obtained confirmed that hypothyroidism causes marked structural changes in the ductus epididymis and could adversely affect the maturation and motility of sperm.

Epididymal scanning electron microscopy study in hypothyroid rats.

The purpose of this research was to investigate, using scanning electron microscopy, the effect of hypothyroidism on the ultrastructure of the rat cauda epididymis. Thyroidectomy was obtained by ip injection of 270 muCi of 131I per rat. One month later, several portions of cauda epididymis were examined. Morphological and physiological differences were detected in the cauda epididymis of the hypothyroid animals when compared to the control normal rats. The hypothyroid condition was associated with important changes in the luminal surface of the cauda epididymis epithelium. Broken, oblique, and loss of stereocilia, denuded epithelial cells, and flattening of the tubule were observed. The results confirm that hypothyroidism causes marked structural changes in the cauda ductus epididymis and could be adversely affect sperm maturation motility.

High-affinity binding of T3 to epididymis nuclei.

Thyroid hormones play an important role in epididymal function. Hypothyroid animals experience a significant decrease in the number and forward motility of sperm and a remarkable impairment of epididymal morphology. However, it is yet unknown if such activity is due to direct actions of iodothyronines on the target epididymis. The eventual identification of T3 receptors in the nucleous of epididymal cells becomes relevant. For this reason, the authors searched for specific high-affinity binding of T3 to these nuclei. Twenty prepuberal male Wistar rats were used. The testes and epididymis were approached as one unit through a scrotal incision. The fat-free epididymides were subjected to standard techniques to prepare the nuclei for incubations with 125I-T3 concentrations, ranging from 0.5 x 10(-9) to 2.0 x 10(-11) M. Calculations of association constants and binding capacities were performed according to Scatchard. A single binding site with a Ka of 3.06 +/- 0.6 x 10(9) M(-1) or Kd of 3.26 +/- 0.6 x 10(10) M and a maximal binding capacity of 0.11 +/- 0.02 pmol T3/microg DNA were observed. It is concluded that these nuclei contain a specific T3 receptor. This finding strongly suggests that thyroid hormones have direct effects on the epididymis.

Changes in the epididymal ultrastructure in hypothyroid rats.

The purpose of this research was to investigate the effect of hypothyroidism on the ultrastructure of the rat cauda epididymis. Thyroidectomy was obtained by i.p. injection of 270 microCi of 131I per rat. One month later, several portions of cauda epididymis were examined in an electron microscope. Morphological and physiological differences were detected in the cauda epididymis of the hypothyroid animals when compared to the control normal rats. The hypothyroid condition was associated with a decrease in the height of the cells and diminution of the internal lumen, number of mitoses, and chromatin decondensation. Hypothyroidism produces a remarkable impairment of epididymal morphology that could be mainly responsible for the functional alterations that lead to the dramatic slowing of spermatozoa motility, commonly seen in severe thyroid insufficiency.

Thyroid gland and epididymal sperm motility in rats.

The purpose of this research was to investigate the effect of hypofunction of the thyroid gland, caused by radioactive suppression of the gland, on the pattern of spermatozoa motility in different segments of the rat epididymis. Thyroidectomy was obtained by i.p. infection of 270 microCi of I-131. After about 30 days, the animal reached hypothyroidism as determined by serum level of T4. When the motility pattern of the sperm obtained from the epididymis of normal rats was compared to that of hypothyroid animals, a drop in the parameter of path velocity (VAP), progressive velocity (VSL), and track speed (VCL) were detected. Hypofunction was associated with decreasing sperm motility in the epididymis. In thyroidectomized rats injected with T4, no sperm motility changes were observed.

The effects of cross-linked hemoglobin on regional vascular conductance in dogs.

Hemoglobin (Hgb) solutions cause systemic vasoconstriction, which might limit their use as intraoperative blood substitutes. This constriction is thought to be caused by interaction between Hgb and nitric oxide (NO). To determine whether alpha-alpha cross-linked hemoglobin (XL-Hgb) interferes with NO-mediated vasodilation caused by acetylcholine (ACh) and sodium nitroprusside (NTP), we infused these compounds into the femoral, superior mesenteric, and circumflex coronary arteries of anesthetized dogs (n = 6) before and after partial exchange transfusion with XL-Hgb. Additional animals (n = 6) were studied after treatment with 5% albumin. XL-Hgb administration increased mean arterial pressure (MAP) from 81 +/- 5 to 112 +/- 8 (P < 0.05). Albumin reduced MAP from 84 +/- 4 mm Hg to 76 +/- 4 mm Hg (P < 0.05). Vascular conductance after XL-Hgb decreased in the femoral artery, was not changed in the mesenteric bed, and increased modestly in the coronary artery (from 0.19 +/- 0.03 to 0.26 +/- 0.02 mL x mm Hg(-1) x min(-1), P < 0.05). After albumin, conductance was unchanged in the femoral artery and increased in the mesenteric artery. Conductance also increased in the coronary bed (from 0.25 +/- 0.02 to 0.49 +/- 0.03 mL x mm Hg(-1) x min(-1), P < 0.05). The vasodilator response to ACh in the femoral or mesenteric beds was either unaffected or augmented by either XL-Hgb or albumin. In the coronary bed, XL-Hgb blunted the dilator responses to ACh and NTP, while albumin augmented the coronary dilator responses to ACh. In five additional dogs, the NO synthase inhibitor N(G)-monomethyl L-arginine caused MAP to increase from 85 +/- 4 to 90 +/- 8 mm Hg and blunted the coronary dilator responses to ACh by approximately 25%. Subsequent XL-Hgb administration caused a further increase in MAP to 112 +/- 19 mm Hg (P < 0.05) and also further blunted ACh-mediated vasodilator responses in the coronary circulation. XL-Hgb has complex effects on the circulatory system, including a reduction in the vasodilator responses to ACh and NTP in canine coronary arteries in vivo. The potential impact of these events on patients with significant coexisting disease is unclear.

Evaluation of epididymal function through specific protein on spermatozoa.

Investigations were focused on the characterization of specific epididymal proteins on the human spermatozoa as a representative parameter for epididymal function. An easy and attainable method, suitable for investigators and clinical use, is proposed in this article.

Thyroid gland and epididymal function in rats. II. Sperm motile efficiency.

The epididymis is controlled by the endocrine system and plays an active role in the process of spermatic maturation. In order to extend these studies, our investigations were focused on the relationship between the hypofunction of the thyroid gland and the motility of the caput, corpus, and cauda epididymal spermatozoa. The hypofunction was associated with decreasing sperm motility efficiency. In thyroidectomized rats injected with T-3, no sperm motility changes were observed.

Macromolecular secretion into various segments of the guinea pig epididymis.

The secretion of proteins of different segments of the guinea pig epididymis was studied using micropuncture and radiochemical techniques. Tissue and fluid samples were taken 24-48 hr after intraperitoneal injections of 2 mCi of tritiated lysine. Macromolecular secretion was higher in the caput than in the corpus and cauda. Labelled spermatozoa were detected in smears taken from the caput epididymis 24 hr after injection. Few labelled spermatozoa were found in the corpus and none in the cauda. Since the capacity of epididymal sperm for fertilization is apparently achieved before spermatozoa reach the cauda, the protein synthesized in the epididymal caput and corpus would account for trigering sperm maturation.

Metabolism of amphibian spermatozoa in relation to their motility.

Bufo arenarum spermatozoa were able to sustain motility both under aerobic and anaerobic conditions. In aerobiosis, the oxygen consumption varies between 2.6 and 4.2 microliter O2/10(8) cells/h at 30 degree C. The synthesis of lactic acid by anaerobic spermatozoa demonstrated the existence of an active glycolytic pathway.

Thyroid gland and epididymal function in rats--histological study.

An experiment was designed to determine the relation between the hypofunction of the thyroid gland and the structure of the epididymis. The hypothyroid condition was associated with decreased mitosis, insufficient vascularization, decreased nuclear size, and chromatin decondensation. In thyroidectomized rats injected with T3, no morphological changes in the epididymis were observed.

cAMP in spermatozoa taken from different segments of rat epididymis.

Experimental evidence conclusively indicates that the epididymis is under endocrine control and plays an active role in the process of spermatic maturation.

Anaerobic fertilization of amphibian (Bufo arenarum) eggs.

Mature Bufo arenarum eggs, as well as body cavity oocytes of the same species, have been found to be fertilizable under anaerobic conditions. Anaerobic fertilization was obtained in a medium in which oxygen was replaced by purified nitrogen and in the presence of antimycin in concentrations assuring the complete blockage of respiration.