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J W Funder

Publications and source records attributed to J W Funder.

At least 199 records · Page 11Linked to original sources
PubMed1986

Adrenocorticoid-dependent alpha-lactalbumin synthesis in rat mammary gland explants: antagonist studies.

Though adrenal steroids are required for the production of alpha-lactalbumin by mammary gland explants, the physiological class of steroid activity (mineralocorticoid, glucocorticoid) remains to be established. alpha-Lactalbumin production by mammary gland explants from mid-pregnant rats has been shown in previous studies to be increased by high doses of aldosterone, but not by deoxycorticosterone; in six of 11 experiments corticosterone, the physiological glucocorticoid in the rat, elevated alpha-lactalbumin; in five other studies corticosterone had no effect. In the present studies the mineralocorticoid antagonist, spirolactone, at very high doses (3-10 mumol/l) blocked the stimulatory effect on alpha-lactalbumin levels of both 30 nmol/l corticosterone and 3 nmol/l RU 26988, a pure synthetic glucocorticoid (Type II) receptor agonist. Receptor studies, however, indicated that this antagonism is consistent with Type II, glucocorticoid receptor occupancy by spirolactone. Since deoxycorticosterone is without agonist effect, and only very high doses of spirolactone affect alpha-lactalbumin synthesis, we conclude that the effect of adrenal steroids on alpha-lactalbumin production is a manifestation of glucocorticoid and not mineralocorticoid activity.

Aldosterone↗
PubMed1986

Nuclear localization of type 1 aldosterone binding sites in steroid-unexposed GH3 cells.

The nuclear localization of unoccupied oestrogen receptors has been demonstrated in MCF 7 (human breast tumour) cells by immunocytochemistry, and in GH3 (rat pituitary tumour) cells by enucleation techniques. The present study shows, by similar enucleation techniques, that high affinity (Type 1) aldosterone binding sites are similarly located in the nucleus of steroid-unexposed pituitary GH3 cells. It is, therefore, suggested that such high-affinity Type 1 sites, which are mineralocorticoid receptors in the kidney and glucocorticoid receptors in the hippocampus, are nuclear-associated proteins in the absence of steroid and are found in the cytosol compartment only upon cell disruption.

Cell Line↗
PubMed1986

Anterior pituitary cells from Brattleboro (di/di), Long-Evans and Sprague-Dawley rats contain immunoreactive arginine vasopressin.

A radioimmunoassay specific for arginine-vasopressin (AVP) was used to establish the presence of immunoreactive (ir)-AVP in extracts of anterior pituitary glands from Sprague-Dawley (SD) and Long-Evans (LE) rats (3.05 +/- 1.0 and 1.66 +/- 0.9 ng/gland, respectively). Lower levels of ir-AVP (0.56 +/- 0.26 ng/gland) were detected in anterior pituitary gland extracts from rats with hereditary diabetes insipidus (Brattleboro; di/di). The anterior pituitary gland ir-AVP from each rat strain was further characterized by reverse-phase high-performance liquid chromatography (RP-HPLC). In each case the major peak of immunoreactivity co-migrated with synthetic AVP. By peroxidase-antiperoxidase immunocytochemistry, sparsely distributed cells containing ir-AVP were localized in anterior pituitary sections. Levels of ir-AVP in primary cultures of anterior pituitary cells (from SD rats) increased from 52 +/- 5 pg/10(6) cells at 2 days in vitro to 152 +/- 17 pg/10(6) cells at 3 days; during this period 56 +/- 6 pg/ml ir-AVP was secreted into the culture medium. Fewer than 1% of the cells in these cultures were immunostainable for AVP. These data indicate that the anterior pituitary gland of the Brattleboro, Long-Evans and Sprague-Dawley rat contains ir-AVP, and that there is synthesis and secretion of this peptide in primary cultures of anterior pituitary cells in vitro.

Animals↗
PubMed1986

Elevated plasma levels of pro-opiomelanocortin-derived peptides in sheep following hypothalamo-pituitary disconnection.

We have studied the control of the pituitary-adrenal axis in ovariectomized sheep following hypothalamo-pituitary disconnection (HPD) by following plasma levels of immunoreactive (ir-) products of pro-opiomelanocortin (POMC). In ovariectomized HPD ewes, gonadotropin levels were below detection limits. In contrast, levels of ir-ACTH were modestly but significantly elevated over those in matched ovariectomized control ewes, though cortisol levels were not significantly different; levels of ir-alpha MSH and ir-beta EP (beta-endorphin) were substantially and significantly raised in HPD compared with control plasma. Size exclusion HPLC showed plasma beta EP/beta LPH (beta-lipotropin) levels to be higher in HPD than control ewes. Dexamethasone administration lowered plasma ir-ACTH but not ir-beta EP; in contrast, bromocriptine lowered ir-beta EP but not ir-ACTH. We interpret these data as evidence (1) that the elevated plasma levels of ir-beta EP and ir-alpha MSH post-HPD reflect the release of the intermediate lobe from tonic inhibitory dopaminergic control and (2) that, unlike the gonadotrope, hypothalamic releasing factors are not required for the maintenance of the corticotrope, or for baseline secretion of ACTH from these cells.

Adrenal Glands↗
PubMed1986

Pro-opiomelanocortin messenger ribonucleic acid and posttranslational processing of beta endorphin in spleen macrophages.

We have previously demonstrated low levels of immunoreactive (ir)-beta-endorphin (beta-EP) and ir-ACTH in a subpopulation of mouse spleen macrophages, which is consistent with an involvement of opioid peptides in modulation of immune responses. Gel chromatography studies suggested the presence of an approximately 3.5,000-molecular weight (mol wt) species, putatively beta-EP, an approximately 11.5,000-mol-wt species, putatively beta-lipotropin, and a higher molecular weight species (putative beta-EP precursor, pro-opiomelanocortin (POMC). In this study we have extended our original findings by demonstrating the presence of messenger RNA for POMC by the use of a complementary DNA probe and Northern blot analysis of extracts of mouse and rat spleen. In addition, using high performance liquid chromatography (HPLC), we have shown that the major endorphin species in mouse spleen macrophages is beta-EP1-31, and that there are smaller amounts of each of the acetylated forms, N-acetyl-beta-EP1-16 (alpha-endorphin), N-acetyl-beta-EP1-17 (gamma-endorphin), N-acetyl-beta-EP1-27, and N-acetyl-beta-EP1-31. We interpret these studies as showing that (a) the spleen is an organ of POMC synthesis and that (b) the predominant COOH-terminal product of macrophage POMC is the opiate-receptor active species beta-EP1-31.

Animals↗
PubMed1986

Specificity and mechanism of biphasic action of glucocorticoids on alpha-lactalbumin production by rat mammary gland explants.

RU26988 [11 beta, 17 beta-dihydroxy-17 alpha-(1-propynyl)androsta-1,4,6-trien-3-one], a specific type II (glucocorticoid) ligand with negligible affinity for type I (mineralocorticoid) receptors, increased alpha-lactalbumin production in mammary gland explants from midpregnant rats when cultured in vitro in the presence of insulin (5 micrograms/ml) and rat PRL (1 microgram/ml). The dose-response curve was biphasic, over a 3-300 nM dose range, with maximum at 3-10 nM, followed by a progressive decline toward or to control levels at 300 nM. A similar dose-response curve was obtained with another type II-specific ligand, RU28362 [11 beta, 17 beta-dihydroxy-6-methyl-17 alpha-(1-propynyl)androsta-1,4,6-trien-3-one], and with dexamethasone. This biphasic response had been previously reported for mouse mammary gland explants using cortisol, which binds to both type I and type II receptors. Our experiments, therefore, show that occupancy of type II receptors alone can be responsible for the stimulation at low steroid concentrations, followed by the decrease from peak levels observed at higher steroid concentrations. On the basis of these data, we propose a model to account for these findings, based on ligand binding to a single class of receptors and the putative existence of both turn-on and turn-off glucocorticoid regulatory elements in the nucleus.

Androstanols↗
PubMed1986

High affinity (type 1) aldosterone-binding sites in rat epididymis.

The effect of adrenal steroids on epididymal ion fluxes has previously been shown by ablation/replacement studies. In the present study, we have demonstrated that in the presence of excess RU26988 [3H]aldosterone binds to a single class of sites in epididymal cytosol, with high affinity [dissociation constant (Kd)22 C, 1 nM; range 0.6-1.3 nM] and limited capacity (Bmax 12 +/- 3 fmol/mg protein, mean +/- SE). The specificity of these epididymal sites is identical with that of type 1 sites in other tissues: aldosterone equals corticosterone more than dexamethasone more than testosterone more than dihydrotestosterone. Sixteen hours after 6 micrograms estradiol benzoate im to suppress gonadotropin and testosterone production, available type 1 sites in epididymal, but not renal, cytosols were significantly increased. We interpret these studies as showing 1) that adrenal steroids may modulate epididymal ion fluxes via type 1 receptors; 2) that whether corticosterone and/or aldosterone modulates these fluxes is yet to be determined; and 3) that despite its modest affinity for type 1 sites, testosterone may occupy a proportion of such sites in the epididymis, reflecting its very high local tissue concentration.

Adrenalectomy↗
PubMed1986

Estrogen regulation of kallikrein gene expression in the rat anterior pituitary.

Using a rat pancreatic kallikrein cDNA probe (pcXP39), previously shown to hybridize to kallikrein mRNA in a variety of tissues, we have explored the control of kallikrein gene expression in rat anterior pituitary. Intact female rats have substantially higher levels of AP kallikrein mRNA than intact males; male levels are unaffected by castration, whereas female levels fall markedly postovariectomy. Administration of estradiol benzoate to intact male or ovariectomized female rats causes an increase in anterior pituitary levels of kallikrein mRNA. Since the pattern of responsiveness parallels that of PRL, we have studied GH3 cells grown in the presence and absence of estradiol; in neither instance was kallikrein mRNA above detection limits. Parallel changes were seen on Northern blots and by hybridization histochemistry; on emulsion autoradiography of pituitary sections, scattered positive cells were seen, but precise definition was not possible. We conclude that whereas in the submaxillary gland kallikrein gene expression appears androgen dependent and in the kidney is postulated to be mineralocorticoid regulated, in the anterior pituitary expression of the gene is under estrogen control; and that the local role(s) of pituitary kallikrein, whether precursor processing, control of blood flow, or other effects, would, in turn, appear to be modulated by estrogen in vivo.

Animals↗
PubMed1986

Beta-endorphin and its congeners in rat pituitary and thyroid: effects of propylthiouracil and thyroid hormone administration.

Immunoreactive beta-endorphin (ir-beta EP) and immunoreactive N-acetyl-endorphin (ir-NacEP) have been demonstrated in the rat thyroid by specific RIA and characterized by reverse phase HPLC. In addition, pituitary and thyroid ir-beta EP and ir-NacEP levels have been determined after manipulation of the pituitary-thyroid axis by chronic (21 days) treatment with 1) propylthiouracil (PTU), 2) L-T4, 3) L-T3, or 4) T3 plus PTU. No difference in anterior pituitary or neurointermediate lobe ir-beta EP was seen between controls and treated groups (n = 8/group). In contrast, levels of ir-NacEP were markedly lower (P less than 0.01) in both hypo- and hyperthyroid groups than in controls, in both anterior pituitary and neurointermediate lobe. In the thyroid, levels of both ir-beta EP and ir-NacEP were profoundly depressed (P less than 0.01) in all treated groups, with no change in calcitonin levels, suggesting that the thyroid effect of PTU and T3/T4 may be specific for the synthesis, processing, and/or release of pro-opiomelanocortin derived peptides. The findings in this study suggest 1) that acetylation of pituitary and thyroid beta EP is similarly sensitive to PTU and thyroid hormone administration and 2) that in the thyroid, but not in the pituitary, both PTU and thyroid hormones markedly lower levels of pro-opiomelanocortin-derived peptides.

Acetylation↗
PubMed1986

Immunoreactive arginine vasopressin in the rat thymus.

Immunoreactive arginine vasopressin (ir-AVP), coeluting with authentic nonapeptide on reverse phase HPLC, is present in the thymus of Sprague-Dawley, Long-Evans, and homozygous (di/di) Brattleboro rats, and BALB/c mice. By immunohistochemistry, ir-AVP positive cells are sparse, and do not appear to be lymphocytes. Adrenalectomy and dexamethasone administration to intact rats produces an identical response in terms of thymic ir-AVP, with a rise after 1-2 days followed by a fall to levels below baseline after 8 days. The rise 2 days after adrenalectomy, and the fall 8 days later, were both prevented by administration of aldosterone, but not by corticosterone or dexamethasone to adrenalectomized animals. The role(s) of thymic ir-AVP, and the physiological significance of its mineralocorticoid dependence, remain to be established.

Adrenalectomy↗
PubMed1986

Pregnancy-associated changes in ovarian immunoreactive beta-endorphin in rats.

Ovaries from pregnant and postpartum Sprague-Dawley rats were examined for content of immunoreactive beta-endorphin by radioimmunoassay, and for its localization by the peroxidase-antiperoxidase technique. In addition, the molecular forms of beta-endorphin immunoreactivity were separated by gel chromatography and reverse-phase high performance liquid chromatography (RP-HPLC). Ovaries from rats early in pregnancy showed intense granular cytoplasmic staining of luteal cells, with an even distribution of granular material throughout the cytoplasm. By middle to late pregnancy the staining pattern was changed, with immunoreactive material showing a less granular and unevenly distributed staining pattern and with some areas of the cytoplasm totally devoid of immunoreactive material. The concentrations of immunoreactive beta-endorphin measured during pregnancy were significantly lower than levels in mature non-pregnant rat ovary. The ovarian concentration of immunoreactive beta-endorphin fell progressively during pregnancy and early lactation, returning to normal cyclic rat levels at 20 days post partum. The ovarian concentration of beta-endorphin-like material was lowest at 6 days post partum (0.53 +/- 0.08 ng/g wet weight; mean +/- S.E.M.), representing approximately 10% of the concentration found in pooled ovaries from randomly cyclic adult rats. Gel chromatography revealed only a single peak of immunoreactive beta-endorphin, co-eluting with 3.5 kD molecular weight ovine beta-endorphin (1-31). This contrasts with gel profiles of adult cyclic rat ovary, where large molecular weight species pro-opiomelanocortin (31 kD) and beta-lipotrophin (11.5 kD) are also present. On RP-HPLC the predominant species of low molecular weight immunoreactive material co-eluted with beta-endorphin(1-31).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Aldosterone-receptor deficiency in pseudohypoaldosteronism.

Pseudohypoaldosteronism, a syndrome characterized by salt wasting and failure to thrive, usually presents in infancy as high urinary levels of sodium despite hyponatremia, hyperkalemia, hyperreninemia, and elevated aldosterone levels. We have investigated this syndrome for the possibility of abnormal Type I or "mineralocorticoid-like" receptors, which have intrinsic steroid specificity indistinguishable from that of renal mineralocorticoid receptors and are found in many tissues and cells, including mononuclear leukocytes. We have studied three patients with pseudohypoaldosteronism: the 28-year-old index case in Melbourne (Patient 1) and two siblings in Munich, eight and two years of age (Patients 2 and 3); clinically, Patient 3 had a less severe case than his sister. Percoll-separated control monocytes bound [3H]aldosterone with high affinity (Kd approximately 3 nM) and limited capacity (150 to 600 sites per cell). On repeated examination, no [3H]aldosterone binding was found in monocytes from Patients 1 and 2; in Patient 3, the levels were 62 sites per cell, more than 2 S.D. below those of the control. Levels in the parents of the Munich patients (first cousins) were normal. It appears that pseudohypoaldosteronism is caused by a Type I receptor defect, that the defect may be complete or partial, that transmission may be autosomal recessive, and that the study of patients with pseudohypoaldosteronism may indicate physiologic roles for Type I receptors in nonepithelial tissues.

Adult↗
PubMed1985

Dopaminergic agents differentially alter beta-endorphin processing patterns in the rat pituitary neurointermediate lobe.

We have established the content and molecular species of immunoreactive beta-endorphin (ir-beta-END) and immunoreactive N-acetyl-endorphin (ir-Nac-END) in rat neurointermediate lobe by specific radioimmunoassay (RIA) and high-performance liquid chromatography after chronic administration of dopamine (DA) agonists and antagonists. The DA agonist, bromocriptine, reduces tissue levels of all major immunoreactive species, in particular the C-terminally shortened N-acetylated forms. The DA antagonist, haloperidol, proportionally increases all immunoreactive forms, except Nac-beta-END, thus altering the relative abundance of this species. These data indicate that DA is involved in the control of both tissue levels and processing of beta-END-like peptides in the rat neurointermediate lobe.

1-Methyl-4-phenylpyridinium↗
PubMed1985

The identification and characterization of alpha-N-acetylated beta-endorphin in the human pituitary gland.

By using a radioimmunoassay specific for alpha-N-acetyl beta-endorphin and its C-terminally shortened forms, we have established the presence of immunoreactive alpha-N-acetyl endorphin (irNacEP) in extracts of five postmortem human pituitary glands (2.27 +/- 0.64 ng/gland). This immunoreactivity has been further characterized by subjecting these extracts to reverse-phase high-performance liquid chromatography (RP-HPLC). In all cases the major peaks of irNacEP co-migrated with synthetic human standard alpha-N-acetyl alpha-endorphin (Nac alpha EP), alpha-N-acetyl gamma-endorphin (Nac gamma EP) and Nac beta EP. These studies thus represent the initial demonstration that alpha-N-acetylation of beta-endorphin and its shorter molecular forms occurs in the human pituitary gland.

Acetylation↗
PubMed1985

A kappa-selective opioidergic pathway is involved in the reversal of a behavioural effect of adrenalectomy.

We have shown previously that adrenalectomized rats are immobile for only approximately 30% of a 5 min retest period, 24 h after an initial 15 min swimming exposure, compared with approximately 70% immobility for intact animals. The administration of ketocyclazocine, dynorphin-(1-17) or [Met5]enkephalin[Arg6,Phe7] immediately after initial exposure reversed the effect of adrenalectomy, whereas equimolar doses of morphine sulphate, [D-Ala2,D-Leu5]enkephalin and dynorphin-(1-8) were inactive. MR2266, a kappa-selective partial agonist/predominant antagonist, did not reverse immobility but antagonized the reversing effect of ketocyclazocine. In conjunction with our previous studies, we interpret these data to show that one of the opioidergic pathways for the incorporation of information post-stress is kappa-selective. This kappa selectivity in turn suggests a possible physiological role for prodynorphin-derived peptides in memory.

Adrenalectomy↗
PubMed1985

Progestins specifically suppress alpha-lactalbumin synthesis and secretion.

Mammary gland explants from pregnant (day 12-15) rats were cultured with insulin and prolactin, and their content and secretion of alpha-lactalbumin determined after exposure to a wide range of doses (0.01-300 nM) of the specific synthetic progestin (ORG2058), alone or with a maximally stimulatory dose of the highly specific glucocorticoid RU26988. ORG2058 alone suppressed alpha-lactalbumin synthesis below baseline, with a half-maximal effect at a concentration of less than 0.1 nM; RU26988-stimulated secretion was similarly abrogated by ORG2058, similarly with a half maximally effective dose of less than 0.1 nM. We interpret these data as suggesting that (i) given the specificity and doses of the steroids used the effect of progestins on alpha lactalbumin synthesis is directly via progesterone receptor occupancy, and not by competing with glucocorticoids for glucocorticoid receptors and (ii) given the shift to the left in the alpha-lactalbumin response (half maximal less than 0.1 nM ORG2058) compared with receptor binding (Kd (37 degrees C) greater than 1 nM), one possible model for such sensitivity is that of multiple, independent regulatory elements on the chromatin controlling alpha-lactalbumin gene expression, occupancy of any one of which by an activated progesterone receptor is sufficient to abrogate transcription.

Androstanols↗