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At least 469 records · Page 26Linked to original sources
PubMed1988

Uterine decidualization in hypophysectomized-ovariectomized rats: effects of pituitary hormones.

Decidualization of the endometrial stroma occurs in rats in response to implanting blastocysts or after the application of an appropriately timed artificial stimulus. It is well established that decidualization is regulated by estrogens and progesterone (P). The present study investigated the role of pituitary hormones in this response. Decidualization produced by the bilateral intrauterine injection of 100 microliter sesame oil was compared in ovariectomized (OVX) and hypophysectomized (HYPOX)-OVX rats. All animals were treated with a sequence of 17 beta-estradiol (E2) and P that in OVX rats supported decidualization. As assessed by uterine weights 5 days after uterine stimulation, decidualization was much greater in OVX than in HYPOX-OVX rats (geometric mean uterine weights of 1539 and 376 mg, respectively). To determine the ability of pituitary hormones to restore decidualization in HYPOX-OVX rats, animals were treated with ovine prolactin (oPRL, 2 x 100 micrograms daily), bovine growth hormone (bGH, 2 x 125 micrograms daily), and thyroxine (1 microgram/day, replacement for thyrotropin) in addition to E2 and P. Combined treatment with bGH + thyroxine resulted in decidualization which was not significantly different from that obtained in OVX rats; the effects of bGH and thyroxine were additive. oPRL had no significant effect. Administration of bGH + thyroxine during the prestimulation period resulted in decidualization which did not differ significantly from that obtained when the hormones were administered both pre- and poststimulation; administration during the poststimulation period only, when growth and differentiation of decidual cells occurs, resulted in much less decidualization. Because an increase in endometrial vascular permeability is a prerequiste for decidualization, [125I]-labeled bovine serum albumin was used to assess permeability 8 h after uterine stimulation. Uterine concentrations of radioactivity indicated that endometrial vascular permeability was increased to the same extent in bGH + thyroxine-treated HYPOX-OVX rats as in OVX animals; this increase was significantly reduced in vehicle-treated HYPOX-OVX rats. Because prostaglandins (PGs) are involved in decidualization, the possibility that the reduced responses in vehicle-treated HYPOX-OVX rats were a consequence of a decreased capacity of the uterus to produce PGs in response to the deciduogenic stimulus was investigated. As indicated by uterine PGE and PGF concentrations 15 min after uterine stimulation, uterine PGE and PGF production was increased by the stimulus in both vehicle-treated and bGH + thyroxine-treated HYPOX-OVX rats.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1998

[Correlation of pituitary hormones in serum of male patients with fertility problems].

UNLABELLED: FSH, LH and prolactin serum levels estimations are the part of the most diagnostic procedures in andrology but there is their prediction value under discussion all the time. AIM: To judge the sensitivity of pituitary hormones serum levels estimation as the diagnostic method in male subfertility and to investigate the correlation between FSH, LH and PRL depending on their physiological or pathological ranges. MATERIAL AND METHODS: FSH, LH and PRL serum levels were estimated in 36 males with azoospermia or severe oligozoospermia (density below 5 mln sperm per milliliter) by EIA. The percentage of pathologic values for every hormones was counted. The statistic analyzes (for p. < 0.05) of correlation factor between every couple of hormones were performed in full investigated group and in subgroups which were formed in following way: A-12 men with pathologic FSH serum levels, B-9 men with pathologic LH serum levels and C-24 men with both physiologic gonadotropins serum levels. RESULTS: The percentage of FSH, LH and PRL pathologic values was in all subfertile men: 33%, 25% and 19.4% respectively. The correlation factor for FSH and LH was high in whole group (0.9484), it was the highest in both groups with FSH and LH pathologic levels (almost 1.0). In the group with physiological FSH and LH serum levels this positive correlation was significantly weak but also present (0.4107). The prolactin is completely independent without the correlation with any gonadotropins in any groups. CONCLUSIONS: 1. The sensitivity of the investigations of pituitary hormones during the diagnostic procedures of male fertility disturbances is poor. 2. Gonadotropins and prolactin infertile male serum levels are completely independent. 3. Positive correlation between FSH and LH increases in the pathological range of their values.

Follicle Stimulating Hormone↗
PubMed1977

[Alteration in the secretion of anterior pituitary hormones during dimethylbenzathracene induction of mammary tumors in rats].

In a sensitive strain of Rat (Sprague-Dawley) a deregulation of the secretion of some pituitary hormones was noted in the female during induction of mammary tumors by dimethylbenzanthracene administration. The deregulation occurred quickly and depended on the stage of the estrous cycle. It mainly consists of hyposecretion of gonadotropins. TSH and GH and of hypersecretion of prolactin.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

The impact of euglycemia and hyperglycemia on stimulated pituitary hormone release in insulin-dependent diabetics.

To study the influence of different blood glucose (BG) concentrations on the release of pituitary hormones, the effect of the simultaneous iv administration of LRH (200 micrograms), TRH (400 micrograms), and arginine (30 g/30 min) upon the serum concentrations of LH, FSH, TSH, PRL, and GH was determined in six male insulin-dependent diabetics. BG concentration was clamped by feedback control and an automated glucose-controlled insulin infusion system at euglycemic (BG 4-5 mmol/liter) or hyperglycemic (BG, 14-18 mmol/liter) levels. Increments in serum concentrations of LH, FSH, TSH, and PRL were similar in the euglycemic and hyperglycemic steady states, whereas the GH response to arginine was suppressed during the hyperglycemic clamp (P less than 0.01). Omission of exogenous insulin during hyperglycemia did not modify the observed hormonal responses. Thus, the release of LH, FSH, TSH, and PRL in response to adequate acute stimuli at the pituitary level is not modulated by hyperglycemia in insulin-dependent diabetes, while arginine-induced GH release is suppressed. Since the effect of arginine on GH is most likely mediated by an action on the hypothalamus, the data suggest that elevated glucose concentrations may exert their modulatory influence on GH secretion at the hypothalamic rather than at the pituitary level.

Adult↗
PubMed1983

Effects of excitotoxic amino acids on pituitary hormone secretion in the rat.

The acute effects of administration of 4 excitatory amino acids (n-methyl-DL-aspartic acid (NMA), kainic acid (KA), ibotenic acid (IA) and quinolinic acid (QA] on the serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), growth hormone (GH) and prolactin (PRL) were studied in the rat. NMA-treated rats exhibited increased serum LH and GH concentrations while KA-treated rats-showed increases only in serum GH concentrations. Neither IA nor QA altered adenohypophyseal hormone levels. These endocrine alterations induced by NMA and KA are different from those previously reported after administration of glutamate, another excitatory amino acid. The finding that all of the excitatory amino acids studied did not produce identical effects on anterior pituitary hormone secretion may be due to differential permeability of these substances into the central nervous system or because they act at different subtypes of excitatory amino acid receptors.

Amino Acids↗
PubMedDate not supplied

An interleukin-1-alpha-like neuronal system in the preoptic-hypothalamic region and its induction by bacterial lipopolysaccharide in concentrations which alter pituitary hormone release.

We studied the effect of intravenous injection of lipopolysaccharide (LPS) (30-250 micrograms) on the release of several anterior pituitary hormones as indicated by changes in their concentrations in plasma. Within 30 min after intravenous injection of LPS there was a dose-related stimulation of ACTH release; prolactin (PRL) release was induced only by the highest LPS dose injected (250 micrograms). Even the lowest dose of LPS (30 micrograms) decreased plasma growth hormone (GH) by 60 min. Higher doses lowered plasma GH by 30 min, but thyroid-stimulating hormone release was only significantly inhibited by the highest dose of LPS. The action of LPS seems to be primarily exerted on the central nervous system, since incubation of hemipituitaries with LPS for 3 h in doses ranging from 0.001 to 10 micrograms/ml had no effect on ACTH release. LPS is thought to induce its effects on hormones either by release of cytokines from immune cells which subsequently induce the hormonal changes or possibly by direct action within the hypothalamus. In this report we demonstrate the immunocytochemical localization of a population of interleukin-1 alpha (IL-1 alpha)-like cells in a region extending from the basal forebrain at the level of the diagonal band of Broca, caudally and dorsally to the dorsolateral preoptic region and the hypothalamus at the level of the paraventricular nucleus. Further caudally, IL-1 alpha-like immunoreactive cells were located in the midportion of the amygdala. Two hours after injection of the 125-micrograms dose of LPS, the number of these immunoreactive cells was dramatically increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1987

The influence of naloxone on exercise-induced increase in plasma pituitary hormones and the subjectively experienced level of exhaustion in healthy males.

Opioid peptides seem to play a role as modulators of the pituitary function in man. In the present study, the effect of naloxone on exercise-induced pituitary hormone release and the subjectively experienced level of exhaustion were investigated in nine healthy males. A submaximal work test was performed on two occasions using a bicycle ergometer: 10 min on 50% of maximal working capacity (MWC), immediately followed by 10 min on 80% of MWC. Ten min before exercise, each subject received, in a single-blind randomized order, either a bolus dose of naloxone (100 micrograms/kg) followed by a slow infusion of naloxone (50 micrograms X kg-1 X h-1) or as a control a corresponding volume of the preservatives in the naloxone preparation as a bolus dose followed by an infusion of diluted preservatives. In the control studies, exercise induced a significant increase in GH, PRL, TSH and ACTH. The increase in ACTH was enhanced following naloxone. Naloxone was without effect on exercise-induced changes in GH, PRL and TSH. An increased level of exhaustion was experienced on 80% of MWC during naloxone. It is concluded that opioid receptors with a moderate sensitivity to naloxone are involved in the regulation of the ACTH response to exercise and also influence the subjectively experienced level of exhaustion.

Adrenocorticotropic Hormone↗
PubMed2006

Waxing and waning of a pituitary mass in a young woman with combined pituitary hormone deficiency (CPHD) due to a PROP-1 mutation.

We describe a 23-yr old woman with congenital combined pituitary hormone deficiency (CPHD) diagnosed at 10 years of age and a large sellar mass discovered at the age of 19 years, when her first pituitary MRI was performed. The mass (height: 13 mm) extended to the suprasellar region, close to the optic chiasm, showed signal hyperintensity in T1- and hypointensity in T2-weighted images, with no enhancement after gadolinium injection. Although these MRI features were suggestive of Rathke's cleft cyst, cystic craniopharyngioma or previous hemorrhage, no visual symptoms, diabetes insipidus and/or hyperprolactinemia were present. In addition, similar MRI findings had been previously described in a few cases of CPHD due to PROP-1 mutations, which prompted us to carry out a molecular study before any therapeutic decision was made. A 301302delAG PROP-1 mutation was found in her DNA and the patient was closely followed through ophthalmologic evaluation and pituitary MRI scans. During a 3.6-year follow-up, we were able to document a marked initial growth followed by shrinkage and recurrent growth of the PROP-1 sellar mass. The patient remains free of compressive neuro-ophthalmological signs, suggesting that surgical intervention is unnecessary in these cases. However, they must be followed closely with sellar MRIs and campimetry until the mass completely regresses.

Adult↗
PubMed1991

Gene structure of chum salmon somatolactin, a presumed pituitary hormone of the growth hormone/prolactin family.

From a chum salmon genomic DNA library, clones coding for somatolactin (SL), a presumed pituitary hormone belonging to the GH/PRL family, were isolated and analyzed. The salmon SL gene was 16 kilobases (kb) in length, this being the largest among mammalian GH (approximately 2 kb) and PRL (approximately 10 kb) and fish GH (approximately 4 kb) genes. As in the case of mammalian GH/PRL genes, the salmon SL gene was comprised of five exons in contrast to rainbow trout and Atlantic salmon GH genes, which each have six exons. Upstream from the transcriptional initiation site were found one TATA box identical to those of mammalian PRL genes and four consensus sequences corresponding to the Pit-1/GHF-1 binding element which is essential to the expression of mammalian GH and/or PRL genes. The similarity in amino acid sequences and organization of the SL gene with mammalian GH/PRL genes indicates that the SL gene is quite likely produced from an ancestral gene common to GH/PRL genes by gene duplication. Based on these considerations, an evolutionary model for the GH/PRL/SL gene family was made and shows the common ancestral gene to originate not from duplication of a primordial gene but from shuffling of independent exons and a regulatory sequence.

Amino Acid Sequence↗