Localization of histamine in uterine structures

By means of luminescent-histochemical method of Cross, Even, Rost histamine is revealed in all uterine structures. Visual and fluorometric data demonstrate uneven distribution of histamine in the organ's structures. A high content of histamine is specific for macrophages and mast cells, less high--in tegmental epithelium and endometrial glands. A low level of histamine have endometrial stroma, smooth myocytes, cells of the serous membrane and vessels. Basing on the literature data, concerning various sensitivity of the uterine tissues to estrogens and regarding effect of the estrogens upon histamine metabolism in the uterine and regarding interconnection of the histamine receptors in the uterus and the estrogens, a suggestion is made that various contents of histamine in the uterine structures depend on various amount of the histamine receptors in them and on different abilities of the uterine tissues to inactivate histamine. The ability of macrophages to accept free forms of bioamines, as it is described in the literature, evidently can be spread to the uterine macrophages, where a high content of histamine is revealed.     

Localization of histamine and histamine H2-receptor antagonists in the gastric mucosa.

Synopsis Histamine stimulates acid secretion by the parietal cell and this secretion is inhibited by the histamine H₂-receptor antagonists. Whole body autoradiography showed that radioactivity from¹⁴C-histamine was localized in the artery walls of the stomach and in the muscularis mucosae, but that the level in the fundic mucosa was the same as the blood.When the H₂-receptor antagonists burimamide, metiamide and cimetidine were labelled with³⁵S,¹⁴C or³H and dosed to rats, whole body autoradiography showed that the stomach was predominantly labelled in the glandular mucosa from 5 to 120 min after administration. Microautoradiography in the rat and dog after intravenous injection of [³H] metiamide or [³H] cimetidine demonstrated an uptake of tritium in the parietal cell cytoplasm that was 3- to 4-times greater than that found in adjacent peptic cells or areas of muscularis mucosa. The preferential labelling persisted at a low level up to 6 h after injection in the rat. The localization of radioactivity from the H₂-antagonists in the parietal cell cytoplasm correlates well with their pharmacological activity in preventing acid secretion from this cell.     

In vitro regulation of sheep ovarian surface epithelium (OSE) proliferation by local ovarian factors

The ovarian surface epithelium (OSE) forms a lining around the entire ovary and actively participates in the ovulatory cycle. To investigate how specific growth factors and hormones affect OSE proliferation, the present study used sheep as a model to examine the effects of follicular and luteal products on the proliferation of sheep OSE cells in culture, and to analyse the influences of large antral follicles and corpora lutea (CL) on the expression of gonadotrophin receptors (FSHR and LHR) in the OSE. In the present study, follicular fluids from medium and large follicles, and extracts of corpora lutea stimulated the growth of OSE cells. The results of the present study showed that factors in the follicular fluid can induce OSE proliferative activity, and this stimulation effect could not be attributed to steroids in the follicular fluid since oestrogen and progesterone treatments failed to stimulate OSE cells. The expression of LH and FSH receptors over large follicles (5 mm or larger) was two and four times higher than those over stroma and CL, respectively. In conclusion, OSE proliferation in cycling sheep is associated with underlying developing follicles and CL, mediated by, at least in part, the up-regulation of gonadotrophin receptors, and facilitated by the action of mitogenic glycopeptides and growth factors, but not steroids.     

Gonadotropic regulation of prostaglandin production by ovarian follicular cells of the pig

Prepubertal gilts were treated with 750 IU pregnant mare's serum gonadotropin (PMSG) and 72 h later with 500 IU human chorionic gonadotropin (hCG) to induce follicular growth and ovulation. Dispersed granulosa cells (GC) and theca interna cells (TC) from follicles of gilts 72 h (GC-72 and TC-72, respectively) and 108 h (GC-108 and TC-108 h, respectively) after PMSG treatment were cultured for 0, 12, 24, and 36 h in medium with or without luteinizing hormone (LH), dibutyryl cyclic adenosine 3',5'-monophosphate [Bu)2cAMP), calcium ionophore (A23187), and/or arachidonic acid (AA), and the production of prostaglandin E2 (PGE) and prostaglandin F2 alpha (PGF) was measured by radioimmunoassay. TC-72 was the principal source of PGs 72 h after PMSG. At 108 h, the production of PGE and PGF by GC was increased 10- and 30-fold, respectively, whereas corresponding increases by TC were 2-fold. LH and A23187 significantly stimulated PGE and PGF production by both GC-72 and TC-72, but only thecal PG production was stimulated by (Bu)2cAMP. LH had minimal or no effect on PG production by GC-108 and TC-108, but A23187 (GC-108, TC-108) and (Bu)2cAMP (TC-108) were stimulatory. Basal PG production by GC-72, GC-108, and TC-108 was stimulated by AA. However, production by GC and TC cultured in medium containing AA and LH, A23187, or (Bu)2cAMP was not different from that produced by AA alone. These findings suggested that GC and TC can synthesize PGs in vitro, but AA availability is rate-limiting in GC. After exposure to hCG in vivo, the capacity of both cell types to produce PGs is increased but is limited by AA availability.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cyclic AMP in sheep ovarian follicles: site of production and response to gonadotrophins.

This study was undertaken (i) to establish a relationship between cyclic AMP (cAMP) production and the degree of LH and FSH stimulation; (ii) to determine the effects of various gonadotrophins on follicular formation of cAMP; and (iii) to identify the precise intrafollicular site of cAMP formation. The formation of cAMP increased rapidly in follicles exposed to LH. Maximum concentrations were reached after 90 min and were maintained for 180 min. Extracellular release of cAMP increased steadily throughout the 180-min experimental period. Tissue levels of cAMP increased proportionally and significantly when LH concentrations in the medium were increased from 0 to 200 mi.u. ml-1. Tissue levels of cAMP were significantly increased by HCG, prostaglandin E-2 and noradrenaline, but not by prolactin, prostaglandin F-2alpha, serotonin or melatonin. Cyclic AMP formation occurred predominantly in the thecal compartment; the membrana granulosa contributed less than 3% of the total amount of cAMP formed after gonadotrophic stimulation. A significant amount of cAMP from the thecal cells was released into the extracellular compartment and appeared to pass into the granulosa cells.     

Metabolic and hormonal responses to cooling the fetal sheep in utero

The metabolic and hormonal effects of cooling 10 fetal sheep in utero (115-142 days of gestation) for 2h were studied. The fetal core temperature fell by 2.81 +/- 0.14 degrees C while the maternal temperature fell 0.86 +/- 0.15 degrees C. This hypothermia caused a significant rise in the fetal and maternal plasma glucose concentrations (P less than 0.001) and a fall in the fetal insulin concentrations (P less than 0.01). The fetal plasma lactate and cortisol concentrations rose rapidly (P less than 0.01) while the growth hormone fell (P less than 0.01) and remained low until cooling ceased when a rapid rebound occurred. There was no significant change in any of the fetal iodothyronines and no elevation of nonesterified free fatty acid concentrations, in contrast to the rapid rise (P less than 0.01) which occurred when newborn lambs were cooled. These observations demonstrate that appropriate glucose, insulin, lactate and cortisol responses to hypothermia have differentiated by 120 days of gestation. However, neither a thyroid hormone response nor an elevation in free fatty acid levels was observed. Thus not all components of the thermogenic response to hypothermia can be demonstrated in the late gestation fetail sheep in utero.     

Localization of beta-endorphin in tetrahymena by confocal microscopy. Induction of the prolonged production of the hormone by hormonal imprinting

The unicellular Tetrahymena has hormone receptors and hormones which are characteristic of higher vertebrates, as well as similar signal transduction pathways. In the present experiments, immunocytochemistry and confocal microscopy were used to study the presence and localization of beta-endorphin in Tetrahymena pyriformis GL. Endorphin (or endorphin-like material) was localized in the cortical structures, oral field, cilia and nuclear envelope. One-hour treatment with beta-endorphin ('hormonal imprinting') increased the presence of immunocytochemically demonstrable endorphin immediately and after 24 h, and was especially strong after 96 h of treatment. Simultaneous treatment with naloxone, an opioid antagonist, did not inhibit endorphin effect, but had an additive effect on endorphin production. Naloxone alone induced a very intensive accumulation of endorphin 96 h after treatment. The results support the possibility of a hormone production being induced by the imprinting procedure, but the imprinter-like effect of naloxone also points to the importance in this case of non-discriminatory receptors also being involved in the process.     

The effect of stage of estrous cycle and follicular maturation on ovarian inhibin production in sheep

Twenty-four Scottish Blackface ewes (mean weight 50.0 +/- 0.1 kg with ovulation rate 1.3 +/- 0.1) were randomly divided into 4 groups of 6 animals. Under general anesthesia, following the collection of a timed sample of ovarian venous blood, the ovaries of these animals were collected either on Day 10 of the luteal phase or 12, 24, and 48 h after a luteolytic dose of a prostaglandin (PG) F2 alpha analogue (cloprostenol 100 micrograms i.m.) administered on Day 10. All follicles greater than 3 mm were dissected from the ovaries and incubated in Medium 199 (M199) at 37 degrees C for 2 h, following which the granulosa cells were harvested and incubated in triplicate for 24 h in M199 with or without ovine FSH or ovine LH. Plasma and culture media samples were assayed for inhibin, estradiol (E2), androstenedione (A4), and testosterone (T) by specific RIA. After correcting for hematocrit, ovarian secretion rates were calculated from the product of the plasma concentration and flow rate. The rate of ovarian inhibin secretion during the luteal phase was similar from ovaries categorized on the basis of presence of luteal tissue (1.0 +/- 0.3 and 0.9 +/- 0.5 ng/min for CL present and absent, respectively), confirming that the ovine CL does not secrete appreciable amounts of inhibin. Inhibin secretion was higher (p less than 0.05) at 12 h after PG-induced luteolysis but not at 24 or 48 h compared to values for luteal phase control ewes. Although ovaries containing large estrogenic follicles (greater than or equal to 4 mm in diameter and classified as estrogenic from in vitro criteria) secreted the most inhibin (55%; p less than 0.05), both ovaries containing large nonestrogenic follicles (33%) and small (11%; less than 4 mm in diameter) follicles secreted appreciable amounts of inhibin. This contrasted strongly with E2 where greater than 80% of the steroid was secreted by large estrogenic follicles. The rate of ovarian inhibin secretion was positively correlated (p less than 0.05) with the rate of E2, A4, and T secretion. Overall, there was no significant effect of stage of cycle on follicular inhibin content after 2 h incubation in vitro, release of inhibin by follicles incubated in vitro, or synthesis of inhibin by granulosa cells cultured in vitro. FSH and LH had no effect on the production of either inhibin or estradiol by cultured granulosa cells. Follicular diameter was positively correlated (p less than 0.001) with follicular inhibin and steroid release. Follicular inhibin content after 2 h incubation in vitro was more highly correlated with inhibin release by incubated follicles (r = 0.7; p less than 0.001) than with inhibin synthesis by granulosa cells in vitro (0.4; p less than 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)     

Inhibin production by bovine ovarian tissues in vitro and its regulation by androgens

No detectable amounts of inhibin were produced by cultured ovarian stroma or luteal tissue. Follicular tissue produced inhibin in vitro and removal of the granulosa cells from the follicle wall caused inhibin production to fall by 80%. Granulosa cells alone had the greatest ability of any ovarian cell type to produce inhibin in vitro, and are probably the major site of follicular inhibin production. Cyproterone acetate at concentrations of 35 and 350 microM inhibited basal and testosterone (3.5 microM)-stimulated inhibin production by cultured intact follicle wall and granulosa cells. In addition, each concentration of cyproterone acetate inhibited progesterone but not oestradiol-17 beta production by the follicle wall and granulosa cell cultures. The synthetic, non-aromatizable androgens, methylestrenolone and mesterolone, at concentrations of 5 and 25 microM, mimicked the effect of testosterone and stimulated granulosa cell inhibin production, methylestrenolone being the more potent. These findings provide further evidence that androgens regulate follicular inhibin and progesterone production and that these may be receptor-mediated processes, and suggest that inhibin production may be a general property of androgenic compounds. Preliminary examination of the physicochemical characteristics of inhibin indicated that the inhibin activity of bovine granulosa cell culture medium was (a) retained by an Amicon XM100A filter with a nominal molecular weight cut-off point of 100 000; and (b) destroyed by heating to 80 degrees C for 30 min.     

The hormonal regulation of de-etiolation

De-etiolation involves a number of phenotypic changes as the plants shift from a dark-grown (etiolated) to a light-grown (de-etiolated) morphology. Whilst these light-induced, morphological changes are thought to be mediated by plant hormones, the precise mechanism/s are not yet fully understood. Here we provide further direct evidence that gibberellins (GAs) may play an important role in de-etiolation, because a similar light-induced reduction in bioactive GA levels was detected in barley (Hordeum vulgare L.), Arabidopsis (Arabidopsis thaliana L.), and pea (Pisum sativum L.). This is indicative of a highly conserved, negative-regulatory role for GAs in de-etiolation, in a range of taxonomically diverse species. In contrast, we found no direct evidence of a reduction in brassinosteroid (BR) levels during de-etiolation in any of these species. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Epididymal functions and their hormonal regulation

The epididymis is a complex organ which maintains a specific intraluminal environment thought to be important for effecting sperm maturation in proximal regions and sperm storage in distal regions of the duct. The composition of the internal milieu is achieved both by transport between blood and lumen (and vice versa) and by synthesis and secretion into the lumen. Several low-molecular weight organic molecules achieve high concentration in the epididymal lumen, but their functions in the events of sperm maturation and storage still remain unclear. Metabolic processes occurring within epididymal tissue and the absorptive and secretory activity of the epididymal epithelium are regulated by androgens. The synthesis of some, but not all, secretory proteins is also androgen-dependent. In addition to androgens, other hormones and local testicular factors may influence epididymal function. There is now increasing evidence that epididymal-specific and androgen-dependent secretory proteins play a fundamental role in modifying the surface characteristics of sperm in preparation for the events of fertilization.