Lack of effect of hormones and inducers of intracellular messengers on plasminogen activator production by bovine embryos in vitro

Several hormones and inducers of intracellular messengers, known to affect plasminogen-activator (PA) production in other systems, were investigated for putative effects on bovine embryos. Day 8 embryos were cultured for 5 days in a humidified atmosphere of 5% CO2 in air at 37 degrees C in media containing different concentrations of progesterone, oestradiol, dexamethasone, retinoic acid, dibutyryl cyclic AMP (dbcAMP) and phorbol myristate acetate (PMA). At intervals of 24 h, the medium was recovered for PA analysis and overall embryonic diameter was measured. While none of the hormones and agents tested affected PA production (P > 0.05), dimethyl sulfoxide, which was used to dissolve PMA, inhibited PA production during the first 72 h of culture (P < 0.05). PA production was affected by duration of culture (P < 0.05). Concentrations of plasminogen activator in the media were low during the first 48 h, had increased after 72 and 96 h in culture, and either remained high or decreased slightly toward the end of the culture period. With the exceptions of dbcAMP and PMA, the hormones tested in this study did not affect embryonic size. Dibutyryl cAMP caused a progressive decrease in embryonic diameter. PMA resulted in embryo death at high concentrations but at lower concentrations it enhanced overall embryonic diameter throughout the time of culture (P < 0.05). These results suggest that cultured bovine embryos produce PA in a fixed, time-dependent manner, independent of exogenous hormonal regulation.

Influence of corpus luteum age on the steroidogenic response to exogenous human chorionic gonadotropin in normal cycling women

OBJECTIVE

The null hypothesis of this study is that the patterns of steroid secretion exhibited by the human corpus luteum in response to exogenous human chorionic gonadotropin stimulation are independent of corpus luteum age at the time of treatment.

STUDY DESIGN

Twenty-five normally cycling women in whom the midcycle urinary luteinizing hormone surge (luteal day 0) was identified and from whom blood samples were obtained daily from cycle day 11 until menses were prospectively randomized to receive no treatment (group I, n = 5) or exogenous human chorionic gonadotropin 5000 IU administered intramuscularly on luteal day 0 (group II, n = 5), +4 (group III, n = 5), +8 (group IV, n = 5), or +12 (group V, n = 5). Serum concentrations of estrone, estradiol, progesterone, 17-hydroxyprogesterone, and androstenedione were measured by specific radioimmunoassays in all subjects; serum human chorionic gonadotropin concentrations were determined by immunoradiometric assay in treated subjects.

RESULTS

Serum human chorionic gonadotropin levels (mean +/- SEM) were virtually identical among treatment groups (p greater than 0.05). Luteal phase duration (mean +/- SEM) was prolonged (p less than 0.05) only in group V (18.4 +/- 0.5 days) compared with untreated subjects (group I 13.8 +/- 0.7 days). In all groups estrone and 17-hydroxyprogesterone concentrations closely paralleled those of estradiol and progesterone, respectively. Steroid data and progesterone/estradiol ratios (mean +/- SEM) in groups I and II were indistinguishable and were combined (control, n = 10). Group III subjects exhibited patterns of steroid secretion similar to groups I and II, although progesterone was moderately increased after human chorionic gonadotropin treatment. In groups IV and V, progesterone increased (p less than 0.05) 1 day after human chorionic gonadotropin and remained elevated for 5 to 6 days; a 4-day rise (p less than 0.05) in estradiol began 3 days after treatment, and androstenedione rose modestly in parallel. Progesterone/estradiol ratios in groups III through V increased (p less than 0.05) approximately twofold after human chorionic gonadotropin treatment and remained elevated for 4 to 5 days.

CONCLUSION

The human corpus luteum exhibits distinct age-dependent patterns of steroid secretion in response to exogenous human chorionic gonadotropin stimulation, an observation that may have clinical implications regarding the empirical use of exogenous human chorionic gonadotropin in support of luteal function.

Effect of FSH, LH, LH-RH and arginine-vasotocin on the production of steroids, nonapeptide hormones and cGMP by rabbits granulosa cells isolated at different stages of reproductive cycle

Granulosa cells isolated from ovaries of non-cycling, cycling and pregnant rabbits of the same age were cultured in vitro either without or with pFSH (1 micrograms/ml), bLH (1 IU/ml), LH-RH (25 ng/ml) or arginine-8-vasotocin (100 ng/ml). The production of immunoreactive progesterone, estradiol-17 beta, oxytocin, arginine-8-vasopressin and cGMP was analyzed. The gonadotropins did not show any significant effects on the cells isolated from non-cycling and cycling rabbits, but not from these of pregnant ones. LH-RH inhibited and vasotocin stimulated progesterone production. All hormones used stimulated estradiol release from cells of non-cycling rabbits, while in a case of cycling animals no change was found. In the cell from pregnant females the release of estradiol was enhanced after LH treatment only. The treatment with FSH and LH (but not with LH-RH or vasotocin) resulted in a remarkable rise of granulosa vasopressin surge irrespectively to the reproductive stage. Oxytocin production by granulosa cells incubated either without or with LH, LH-RH or vasotocin was undetectable. However, FSH strongly stimulated oxytocin release. FSH and in lesser extent, LH or LH-RH (but not vasotocin) activated granulosa cGMP production in the cells from cycling and pregnant (but not from non-cycling) animals. It was also found that, in contrast to other reproductive stages, basal progesterone release from the cells of pregnant rabbits was increased, while in a case of non-cycling animals the basal estradiol release was decreased and that of cGMP was increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Steroid hormone synthesis by a vaccinia enzyme: a new type of virus virulence factor

Vaccinia virus open reading frame (ORF) SalF7L has 31% amino acid identity to human 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD). Here we show that SalF7L encodes an active 3 beta-HSD, by the conversion of pregnenolone to the steroid hormone progesterone. The gene is transcribed early during infection into a 1.4 kb mRNA from an initiation site 12 bp upstream of the ORF. An antiserum raised against bacterially expressed SalF7L immunoprecipitated a 38 kDa polypeptide from infected cells, but not from mock infected cells or from cells infected with a mutant virus from which the SalF7L ORF had been removed. Deletion of the gene had no effect on virus replication in CV-1 cells in culture, yet the deletion mutant was attenuated when intranasally inoculated into mice. This steroid hormone synthesizing enzyme is a novel type of virus virulence factor.

Characterisation of a human glioblastoma cell line (LI) expressing hypothalamic and pituitary hormones

The human glioblastoma cell line LI showed morphological features typical of its neuroectodermal origin. Cells were positive by immunofluorescence to GFAP, MHC class II, and L1 determinants. Cytogenetic analysis showed the presence of a modal chromosome number of 63, ranging from 58 to 69 chromosomes (DNA index was 1.6). Northern blot analysis demonstrated the presence of mRNA transcripts specific for transglutaminase C (type II or "tissue"), growth-hormone releasing-hormone (GHRH), insulin-like growth factor II (IGF-II), and proopiomelanocortin (POMC). The GHRH mRNA was present in two different sizes, one similar to the normal hypothalamic species of 0.75 kb, whilst the second species was a large transcript of approximately 10 kb size. Treatment with 5 microM retinoic acid or 5 mM alpha-difluoromethylornithine for 5 days sharply reduced the growth rate and also induced modulation of the ultrastructure and antigenic profile. This cell line may be useful to study glial differentiation and the relationship of GHRH, IGF-II and POMC expression with differentiation in neuroectodermal tumours.

Differentiation of the fetal gonad

Gonadal differentiation may be divided into four stages: pregonadal, indifferent, primary sex differentiation, and secondary sex differentiation. Sertoli cells appear at 6-7 weeks and Leydig cells differentiate at 8 weeks, but in ovaries, primary sex differentiation occurs much later. Testosterone secretion peaks at 12-16 weeks causing male secondary sex development together with the appearance of anti-Müllerian hormone. Fetal testis is able to synthesize and secrete inhibins. Lower circulating luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels in male than in female fetuses at midgestation suggest that the fetal pituitary is already responsive to the gonadal hormones. Placental human chorionic gonadotrophin may regulate testosterone synthesis at midgestation, and both LH and FSH are likely to have some regulatory effect on fetal gonads during the last third of gestation.

[Apud cells in endometrial cancer]

55 endometrial carcinomas containing apud cells are studied. Correlation between the endocrine-metabolic disturbances and mitotic index, on the one hand, and number of apud cells and their product on the other, is revealed. If the percentage of apud cells is above 20 of all parenchymal cells, low mitotic index in the tumour, marked production of serotonin, calcitonin and other hormones and high incidence of endocrine disturbances together with a relatively favourable prognosis are observed. Low number of apud cells associated with high mitotic index and high incidence of unfavourable outcomes while the hormone production and endocrine disturbances were rare or absent.

[Primary empty sella turcica: clinical aspects and hormonal study of 15 cases]

The goal pursued has been to analyze clinical observations and hormonal studies of patients with empty sella turcica (EST), in order to review this disorder and determine if it can be considered a real syndrome. Fifteen patients with EST (3 men and 12 women) and mean age of 45.6 +/- 17.9 years have been prospectively studied. In the hypothalamus-hypophysis study, reserves of thyrotropin (TSH), prolactin (PRL), gonadotropins (FSH and LH), growth hormone (GH), adrenocorticotropin (ACTH) and cortisol were assessed. In addition, thyroid hormones and, for men, testosterone, were determined. The pathogenic mechanism was explained in two cases (13.3%). We registered headache in 10 patients, obesity in 8, arterial hypertension in 2 and diabetes mellitus in 2. Multiparity antecedent was found in 2 cases. The hormonal study was abnormal in two cases (40%). Most common abnormalities were hyperprolactinemia (3 cases), deficit of gonadotropins (3 cases), without coexisting both of them in any case, and deficit of GH (2 cases). EST is frequently associated with endocrine disfunction, although clinical implications are rare. The absence of common clinical manifestations in most cases questions the EST as a real syndrome.

Regulation of steroid hormone biosynthesis. Identification of precursors of a phosphoprotein targeted to the mitochondrion in stimulated rat adrenal cortex cells

Two short-lived precursor proteins, pp37 and pp32, of the mitochondrial phosphoprotein pp30 (formerly denoted as ib) have been detected in Bt2cAMP-stimulated rat adrenal cortex cells, incubated at 25 degrees C or with 1,10-ortho-phenanthroline at 37 degrees C. Subsequently, these two precursor proteins were also identified in cells incubated at 37 degrees C, where they are present only at low levels due to their short half-life. pp30 is produced in several steroidogenic tissues in response to trophic hormone or second messenger analogue. pp37 and pp32 are also phosphoproteins located in the mitochondrion that are produced in response to cAMP analogue and give rise to proteolytic peptide maps similar to that of pp30. As for pp30, inhibition of cytosolic translation prevents the production of pp37 and pp32. The larger precursor protein pp37 has an apparent molecular mass of 37 kDa, an isoelectric point of approximately 7.1, and a half-life at 37 degrees C of 3-4 min. Pulse-chase studies indicate that this protein is processed into the smaller protein, pp32, which has an apparent molecular mass of 32 kDa, an isoelectric point of approximately 6.4, and a half-life at 37 degrees C of 3-4 min. This latter protein is the immediate precursor of pp30. Since ortho-phenanthroline inhibits the mitochondrial processing protease, while the lower incubation temperature slows both protein import and protease processing, the experimental conditions necessary to detect these proteins are consistent with pp37 being a precursor protein that contains two cleavable presequences and is imported into the mitochondrion. The sequential removal of these sequences produces the mature protein pp30.

Hormonal changes following an acute stress in control and somatostatin-immunized pigs

Sixteen Yorkshire pigs (49 +/- 2 kg BW at 17 weeks) were immunized against somatostatin (SRIF; 4 males, 4 females) or its conjugated protein, bovine serum albumin (BSA; controls; 4 males, 4 females). Immunizations were done at 10, 12 and 14 weeks of age. Jugular vein cannulae were surgically inserted at 17 weeks of age. Five d later, half of each sex from the control and SRIF-immunized groups were stressed. The other half were subjected to the same stress 48 hr later. On both days, remaining animals were used as unstressed controls. The stress consisted of 5 min of snare restraint. Blood samples were collected from all pigs on both days at -20, -15, -10, -5, 0 (beginning of stress), 2, 6, 10, 15, 20, 30, 40, 60, 90, 120, 150, 180 and 240 min. Samples were radioimmunoassayed for cortisol, growth hormone (GH), prolactin (Prl), insulin, triiodothyronine (T3), thyroxine (T4) and insulin-like growth factor I (IGF-I). Mean antibody titers against SRIF (1:150 dilution) at 15 weeks were 0.49 +/- .09% and 54.5 +/- 4.9% for control and SRIF immunized pigs, respectively. Gender and immunization against SRIF had no effect on any of the variables measured (P greater than 0.05), except for T3 levels which were greater in females than in males (P less than 0.05). The stress by time of sampling interaction was significant (P less than 0.01) for all hormones measured. Cortisol values almost tripled within 15 min of stress, reaching concentrations above 100 ng/mL. Maximal increases were seen at 2 min for T4 (14%), at 6 min for T3 (36%), at 15 min for Prl (46%) and at 10 min for insulin (141%). An increase of 129% in GH concentration was present at 20 min in stressed pigs; however, an increase of 97% was also seen at 120 min in control pigs. Concentrations of IGF-I decreased (21%) by 60 min in the stressed pigs and remained depressed for up to 150 min. Stress associated with snare restraint, therefore, induces major changes in the concentrations of a series of hormones in growing pigs. On the other hand, immunization against SRIF did not alter any of the hormonal profiles measured. Since snare restraint is widely used to handle pigs during jugular puncture, any study of hormonal secretion in this species should be carried out under carefully controlled conditions in terms of blood sampling technique.

The expression of peptide hormones in normal cells and tumour cells

Insight in the mechanisms of peptide hormone expression has grown explosively by elucidation of gene, mRNA and preprohormone structures for most hormone systems during the 1980s. In addition, information about the structure and substrate specificity of many prohormone processing enzymes is rapidly accumulating in these years. The preprohormones vary considerably in size and organization from poly- to monoprotein structures. According to the structural organization and sequence homology the hormones are grouped in families. The prohormones are processed to bioactive peptides by multiple enzymatic modifications during the intracellular transport from the rough endoplasmatic reticulum to the mature secretory granules. The modifications comprise different proteolytic cleavages and amino acid derivatizations. The same prohormone may be expressed in several different cell types that process the precursor in entirely different ways. Awareness of such cell-specific processing patterns is important for the understanding of ectopic synthesis in neuroendocrine tumours.

Autonomic and hormonal responses after the use of midazolam and flumazenil

Midazolam, like other benzodiazepine agonists, reduces the autonomic and hormonal responses to emotional or surgical stress. This can be seen as a reduction in catecholamine levels after benzodiazepine treatment. The endocrine response with a reduction in cortisol values is mediated by a decrease in ACTH. The adrenal glands are immediately responsive to exogenous ACTH administration as well as to spontaneous recovery from the benzodiazepine action. Flumazenil given alone does not affect the response to emotional stress, neither does it cause any cardiovascular changes. Following benzodiazepine treatment, flumazenil given in a titrated fashion reverses the inhibitory effects of the agonists.

[The study of protein-peptide hormones using genetic engineering methods (review of the literature)]

Use of genetic engineering technique in cloning and sequence assay of cDNA and genes coding for mammal protein and peptide hormones is reviewed. Recent data on molecular aspects of gene reorganization in some inherited disorders are considered involving analytical methods for evaluation of gene activity, especially of genes coding for peptide hormones. Sequence assay of mRNA coding for mammal proopiomelanocortins (precursor of adrenocorticotropic hormone), beta-lipotropic hormones of pituitary body, is discussed.

Coordinated regulation of morphological and biochemical differentiation in a steroidogenic cell: the granulosa cell model

Studies on the dynamic biochemical and morphological events occurring during steroidogenesis in granulosa cells suggest that the organization and expression of the actin-cytoskeleton may play a major role in the transduction of endocrine and paracrine steroidogenic signals, and in the coordination between the organelles involved in this process. Since steroid hormones are not stored intracellularly, regulation of their production is dependent mainly on the expression of genes coding for membrane-bound steroidogenic enzymes. Recently, the expression of oncogenes of the ras family was also implicated in the regulation of steroidogenesis.