Successful in vitro maturation of oocytes in a woman with gonadotropin-resistant ovary syndrome associated with a novel combination of FSH receptor gene variants: a case report

Infertility due to Gonadotropin-Resistant Ovary Syndrome (GROS) is a rare type of hypergonadotropic hypogonadism. Here, we report an original case of GROS, associated with compound heterozygous follicle-stimulating hormone receptor (FSHR) variants, in a woman who achieved a live birth by in vitro maturation (IVM) of her oocytes. This 31-year-old woman consulted our assisted reproduction center for a second opinion after having been advised, because of pervasive high serum follicle-stimulating hormone (FSH) levels, to pursue in vitro fertilization (IVF) with donor oocytes. She presented with primary infertility and progressively prolonged menstrual cycles. Her serum FSH levels were indeed found to be high, but in discordance with a normal anti-Müllerian hormone (AMH) level and antral follicle count. Genetic investigation found the patient to be compound heterozygous for two FSHR variants: I160T, a known pathologic variant, and N558H, which has never been previously reported. As there was no ovarian response to high daily doses of exogenous gonadotropins, IVM was proposed to the patient with success and she finally delivered at term a healthy boy. Effects of the receptor variants were analyzed in heterologous cells. Whereas the I160T mutation blocked FSHR membrane trafficking and FSH-stimulated cAMP-dependent signaling in transfected CHO cells, the novel variant, N558H, functioned equivalently to wild-type FSHR in the assays employed. In conclusion, IVM should always be offered as a first-line therapy to infertile women presenting with GROS. The N558H variant discovered in FSHR is novel, but its functional significance, if any, is unresolved and merits further investigation as it may be associated with a recessive FSHR-related disorder.

IGSF1 Deficiency: Lessons From an Extensive Case Series and Recommendations for Clinical Management

CONTEXT

Mutations in the immunoglobulin superfamily, member 1 (IGSF1) gene cause the X-linked IGSF1 deficiency syndrome consisting of central hypothyroidism, delayed pubertal testosterone rise, adult macroorchidism, variable prolactin deficiency, and occasionally transient partial GH deficiency. Since our first reports, we discovered 20 new families with 18 new pathogenic IGSF1 mutations.

OBJECTIVE

We aimed to share data on the largest cohort of patients with IGSF1 deficiency to date and formulate recommendations for clinical management.

METHODS

We collected clinical and biochemical characteristics of 69 male patients (35 children, 34 adults) and 56 female IGSF1 mutation carriers (three children, 53 adults) from 30 unrelated families according to a standardized clinical protocol. At evaluation, boys were treated with levothyroxine in 89%, adult males in 44%, and females in 5% of cases.

RESULTS

Additional symptoms in male patients included small thyroid gland volume (74%), high birth weight (25%), and large head circumference (20%). In general, the timing of pubertal testicular growth was normal or even premature, in contrast to a late rise in T levels. Late adrenarche was observed in patients with prolactin deficiency, and adult dehydroepiandrosterone concentrations were decreased in 40%. Hypocortisolism was observed in 6 of 28 evaluated newborns, although cortisol concentrations were normal later. Waist circumference of male patients was increased in 60%, but blood lipids were normal. Female carriers showed low free T4 (FT4) and low-normal FT4 in 18% and 60%, respectively, delayed age at menarche in 31%, mild prolactin deficiency in 22%, increased waist circumference in 57%, and a negative correlation between FT4 concentrations and metabolic parameters.

CONCLUSION

IGSF1 deficiency represents the most common genetic cause of central hypothyroidism and is associated with multiple other characteristics. Based on these results, we provide recommendations for mutational analysis, endocrine work-up, and long-term care.

The IGSF1 deficiency syndrome: characteristics of male and female patients

CONTEXT

Ig superfamily member 1 (IGSF1) deficiency was recently discovered as a novel X-linked cause of central hypothyroidism (CeH) and macro-orchidism. However, clinical and biochemical data regarding growth, puberty, and metabolic outcome, as well as features of female carriers, are scarce.

OBJECTIVE

Our objective was to investigate clinical and biochemical characteristics associated with IGSF1 deficiency in both sexes.

METHODS

All patients (n = 42, 24 males) from 10 families examined in the university clinics of Leiden, Amsterdam, Cambridge, and Milan were included in this case series. Detailed clinical data were collected with an identical protocol, and biochemical measurements were performed in a central laboratory.

RESULTS

Male patients (age 0-87 years, 17 index cases and 7 from family studies) showed CeH (100%), hypoprolactinemia (n = 16, 67%), and transient partial GH deficiency (n = 3, 13%). Pubertal testosterone production was delayed, as were the growth spurt and pubic hair development. However, testicular growth started at a normal age and attained macro-orchid size in all evaluable adults. Body mass index, percent fat, and waist circumference tended to be elevated. The metabolic syndrome was present in 4 of 5 patients over 55 years of age. Heterozygous female carriers (age 32-80 years) showed CeH in 6 of 18 cases (33%), hypoprolactinemia in 2 (11%), and GH deficiency in none. As in men, body mass index, percent fat, and waist circumference were relatively high, and the metabolic syndrome was present in 3 cases.

CONCLUSION

In male patients, the X-linked IGSF1 deficiency syndrome is characterized by CeH, hypoprolactinemia, delayed puberty, macro-orchidism, and increased body weight. A subset of female carriers also exhibits CeH.

Cloning of gonadotropin-releasing hormone I complementary DNAs in songbirds facilitates dissection of mechanisms mediating seasonal changes in reproduction

Temperate zone animals exhibit seasonal variation in reproductive physiology. In most cases, seasonal changes in reproductive states are regulated by changes in GnRH1 secretion, rather than synthesis, from the preoptic area (POA)/anterior hypothalamus. An important exception occurs in some songbirds that become photorefractory to the stimulatory effects of long days and show profound decreases in brain GnRH1 protein content. Whether this decline reflects changes in gene expression is unknown because of past failures to measure GNRH1 mRNA levels, due in large part to the absence of available GNRH1 gene sequence in this taxon. Here, we report the first cloning of GNRH1 cDNAs in two songbirds: European starlings and zebra finches. Consistent with the size of the prepro-hormone in other avian and non-avian species, the open-reading frames predict proteins of 91 and 92 amino acids, respectively. Whereas the decapeptide in both species is perfectly conserved with chicken GnRH1, the amino acid identity in the signal peptide and GNRH associated peptide subdomains are significantly less well conserved. At the nucleotide level, the starling and zebra finch coding sequences are approximately 88% identical to each other but only approximately 70% identical to chicken GNRH1. In situ hybridization using radiolabeled cRNA probes demonstrated GNRH1 mRNA expression primarily in the POA, consistent with previous studies on the distribution of the GnRH1-immunoreactive cell bodies. Furthermore, we provide evidence for photoperiod-dependent regulation of GNRH1 mRNA in male starlings. Declines in GNRH1 mRNA levels occur in parallel with testicular involution. Thus, photorefractoriness is associated with decreases in GNRH1 gene expression in the medial POA.

Photoperiod-dependent regulation of inhibin in Siberian hamsters: I. Ovarian inhibin production and secretion

Follicle-stimulating hormone (FSH) stimulates ovarian follicle development and the production of protein hormones including inhibin A and inhibin B. The inhibins are dimeric proteins (alpha-beta(A) or alpha-beta(B)) secreted by growing follicles that suppress FSH in a classical endocrine negative feedback loop. Siberian hamsters, Phodopus sungorus, exhibit seasonal variation in FSH levels. Given the role of inhibin in FSH regulation, we hypothesized that ovarian inhibin expression differs between animals reared in long (16 h light:8 h darkness) and short (6 h light:18 h darkness) photoperiods. To examine inhibin expression in animals housed under long or short photoperiods, hamster inhibin alpha-, beta(A)-, and beta(B)-subunits were cloned and used to detect and localize inhibin subunit mRNA in developing follicles. Ovarian inhibin alpha-subunit mRNA levels were significantly higher in long day-exposed (LD) than in short day-exposed (SD) hamsters. In addition, dimeric inhibin, as well as inhibin alpha-, beta(A)-, and beta(B)-subunit protein levels were higher in the LD than in the SD hamster ovaries.

Photoperiod-dependent regulation of inhibin in Siberian hamsters: II. Regulation of inhibin production and secretion by pregnant mare serum gonadotropin

Inhibin production differs in ovaries of Siberian hamsters (Phodopus sungorus) exposed to long days (LD) or short days (SD). We believe that seasonal differences in serum follicle-stimulating hormone contribute to this difference. However, given the profound photoperiodic differences in follicle maturation, serum gonadotropins alone may not account for all of the observed differences in inhibin processing. To test this hypothesis, we challenged LD and SD female hamsters with exogenous gonadotropins. While both groups responded with increased inhibin expression, the effects were muted in ovaries of SD females and there was no evidence of ovulation in these animals. These data indicate that the ovaries of SD females are not immediately equipped to respond to gonadotropin stimulation. More generally, these data suggest that photoperiodic history affects ovarian inhibin production and secretion in response to gonadotropins.

Disrupted sperm function and fertilin beta processing in mice deficient in the inositol polyphosphate 5-phosphatase Inpp5b

Inpp5b is an ubiquitously expressed type II inositol polyphosphate 5-phosphatase. We have disrupted the Inpp5b gene in mice and found that homozygous mutant males are infertile. Here we examine the causes for the infertility in detail. We demonstrate that sperm from Inpp5b(-/-) males have reduced motility and reduced ability to fertilize eggs, although capacitation and acrosome exocytosis appear to be normal. In addition, fertilin beta, a sperm surface protein involved in sperm-egg membrane interactions that is normally proteolytically processed during sperm transit through the epididymis, showed reduced levels of processing in the Inpp5b(-/-) animals. Inpp5b was expressed in the Sertoli cells and epididymis and at low levels in the developing germ cells; however, mice lacking Inpp5b in spermatids and not in other cell types generated by conditional gene targeting, were fully fertile. The abnormalities in mutant sperm function and maturation appear to arise from defects in the functioning of Sertoli and epididymal epithelial cells. Our results directly demonstrate a previously unknown role for phosphoinositides in normal sperm maturation beyond their previously characterized involvement in the acrosome reaction. Inpp5b(-/-) mice provide an excellent model to study the role of Sertoli and epididymal epithelial cells in the differentiation and maturation of sperm.

Gonadal steroid receptor mRNA in catecholaminergic nuclei of the canary brainstem

Steroid actions in the song system may be modulated by ascending inputs from catecholaminergic (CA) brain nuclei; however, whether these nuclei contain steroid receptors is unknown. Here, we compared the distribution of androgen receptor (AR) and estrogen receptor-alpha (ER-alpha) mRNA with that of tyrosine hydroxylase immunoreactivity (TH-IR) in the brainstems of male canaries. Areas containing AR and ER-alpha mRNA overlapped with areas containing TH-IR cell bodies in the locus ceruleus and the area ventralis of Tsai. The substantia nigra and the midbrain central gray contained both TH-IR and AR mRNA. The presence of AR and ER-alpha within CA cell groups suggests that sex steroid hormones may modulate song production at the site of CA synthesis.

An emerging role for co-receptors in inhibin signal transduction

While many transforming growth factor-beta (TGFbeta) superfamily ligands such as TGFbeta, activin, and the bone morphogenic proteins (BMPs) are critical to the control of growth, differentiation, and cell fate, inhibin has a more limited role and is primarily responsible for the regulation of one hormone from one cell-type in the anterior pituitary. Inhibin is an endocrine hormone, produced by the gonads, that inhibits follicle stimulating hormone (FSH) release from the pituitary gonadotrope. The other hormones in the superfamily do not appear to act in an endocrine fashion, but rather control cell function in a paracrine or autocrine manner. Many components of the TGFbeta/activin/BMP signal transduction pathway have been elegantly defined; however, the mechanism of inhibin action has not been completely dissected. Several cell surface proteins that associate with inhibin have been identified recently, and these molecules may provide the clues necessary to understand how inhibin regulates reproductive function.

Mechanisms of inhibin signal transduction

Inhibin was first identified as a gonadal hormone that potently inhibits pituitary follicle-stimulating hormone (FSH) synthesis and secretion. Although the notion of a nonsteroidal, gonadally derived inhibitory substance was realized in the early 1930s (McCullagh, 1932), identification of the hormone was not accomplished until more than 50 years later. At that time, inhibin was purified from bovine and porcine follicular fluid and was shown to be produced in two forms through dimeric assembly of an alpha subunit (18 kDa) and one of two closely related beta subunits (betaA and betaB, approximately 14 kDa) (Ling et al., 1985; Miyamoto et al., 1985; Rivier et al., 1985; Robertson et al., 1985). Dimers of alpha and betaA and alpha and betaB subunits form inhibin A and inhibin B, respectively. In the process of purifying inhibin, two groups also identified homo- and heterodimers of the inhibin beta subunits (Ling et al., 1986; Vale et al., 1986). These hormones, the activins, were shown to potently stimulate FSH secretion from primary pituitary cultures and are now known to play important roles in growth and development (Woodruff, 1998; Pangas and Woodruff, 2000). Inhibins and activins are considered members of the transforming growth factor-beta (TGF-beta) superfamily of growth and differentiation factors, based on a pattern of conserved cysteine residues in the alpha and beta subunits, similar to other ligands in the family. Identification of the subunit proteins led to the cloning of their cDNAs and subsequently to their chromosomal mapping in several species (Mason et al, 1985,1986; Forage et al., 1986; Mayo et al., 1986; Esch et al., 1987; Woodruff et al., 1987; Barton et al., 1989; Hiendleder et al., 2000). Three additional activin-related beta subunits (betaC and betaE in mammals and betaD in Xenopus laevis) also have been identified but do not appear to play a role in FSH regulation (Hotten et al., 1995; Oda et al., 1995; Fang et al., 1996, 1997; Loveland et al., 1996; Schmitt el al., 1996; O'Bryan et al., 2000; Lau et al., 2000). To date, only one alpha subunit has been reported. The inhibin subunits are expressed in various tissues (Meunier et al., 1988a, 1988b) but the gonads are clearly the primary source of circulating inhibins (Woodruff et al., 1996). While inhibins act in a paracrine role in some tissues (Hsueh et al., 1987), their best-understood roles are as endocrine regulators of pituitary FSH. Activins also were purified from follicular fluid but because circulating activin levels generally are low, most actions of the hormones are likely to be paracrine in nature (Woodruff, 1998). Several reviews in the past decade have clearly and thoroughly addressed the characterization and regulation of the inhibins and activins and their roles in reproductive function (Vale et al., 1988; Ying, 1988; Woodruff and Mayo, 1990; Mayo, 1994; Woodruff and Mather, 1995). In this chapter, we focus our attention on more-recent developments in inhibin research. First, we discuss differential regulation of inhibin isoforms. Specifically, we describe patterns of inhibin A and B secretion in the context of the female reproductive cycle. Second, we review molecular mechanisms of inhibin subunit regulation. Third, while inhibins are best known for their role in pituitary FSH regulation, other functions of the ligands are becoming better understood. We review the animal and human literature addressing the possible role of inhibins in gonadal cancers. While we know "what" inhibins do in various contexts, we have a very limited understanding of "how" the ligands have their effects on target cells. Recently, candidate inhibin receptor molecules have been identified (Draper et al., 1998; Hertan et al., 1999; Lewis et al., 2000; Chung et al., 2000). Next, we detail our current understanding of inhibin signal transduction. Finally, in light of the data reviewed here, we pose questions and outline future directions for inhibin research. While this review is concerned primarily with expression and function of inhibin, activin function and mechanisms of action are described where necessary to shed light on inhibin function. Several reviews of activin's role in reproductive and other processes can be found elsewhere (Woodruff, 1998; Pangas and Woodruff, 2000).

Inhibin binding protein in rats: alternative transcripts and regulation in the pituitary across the estrous cycle

Inhibin binding protein (InhBP) and the transforming growth factor-beta (TGF beta) type III receptor, beta glycan, have been identified as putative inhibin coreceptors. Here we cloned the InhBP cDNA in rats and predict that it encodes a large membrane-spanning protein that is part of the Ig superfamily, as has been described for humans. Two abundant InhBP transcripts (4.4 and 1.8 kb) were detected in the adult rat pituitary. The larger transcript encodes the full-length protein while the 1.8-kb transcript (InhBP-short or InhBP-S) corresponds to a splice variant of the receptor. This truncated isoform contains only the N-terminal signal peptide and first two (of 12) Ig-like domains observed in the full-length InhBP (InhBP-long or InhBP-L). InhBP-S does not contain a transmembrane domain and is predicted to be a soluble protein. Beta glycan was also detected in the pituitary; however, it was most abundant within the intermediate lobe. Although we also observed beta glycan immunopositive cells in the anterior pituitary, they rarely colocalized with FSH beta-producing cells. We next examined physiological regulation of the coreceptors across the rat estrous cycle. Like circulating inhibin A and inhibin B levels, pituitary InhBP-L and InhBP-S mRNA levels were dynamically regulated across the cycle and were negatively correlated with serum FSH levels. Expression of both forms of InhBP was also positively correlated with serum inhibin B, but not inhibin A, levels. These data are particularly interesting in light of our in vitro observations that InhBP may function as an inhibin B-specific coreceptor. Pituitary beta glycan mRNA levels did not fluctuate across the cycle nor did they correlate with serum FSH. These observations, coupled with its pattern of expression within the pituitary, indicate that beta glycan likely functions as more than merely an inhibin coreceptor within the pituitary. A direct role for InhBP or beta glycan in regulation of pituitary FSH by inhibin in vivo has yet to be determined, but the demonstration of dynamic regulation of pituitary InhBP and its negative relation to serum FSH across the estrous cycle is an important step in this direction.

High resolution MRI reveals global changes in brains of Cln3 mutant mice

Batten disease, the juvenile-onset form of neuronal ceroid lipofuscinosis (NCL), is a progressive neurodegenerative disorder of childhood with an age of onset of 5-10 years of age. JNCL is caused by mutations in the CLN3 gene which encodes a membrane protein of unknown function. Magnetic resonance imaging of the brain of juvenile NCL patients has revealed changes in signal intensity and tissue atrophy, predominantly in the cortex and cerebellum. A mouse model for Batten disease was created by targeted disruption of the murine Cln3 gene in order to further understanding of the pathophysiology of Batten disease and to evaluate potential therapeutic approaches. Several features of the disease are displayed by Cln3 mice including accumulation of characteristic storage material in neurons. The aim of this work was to investigate neurodegeneration in the Cln3 mouse model using high resolution magnetic resonance imaging to measure signal intensity ratios in selected regions of interest. Global changes were observed in the brains of 12-month-old mutant mice that mirror those seen in juvenile NCL patients. There is a decrease in signal intensity ratio in grey matter regions including cortex, hippocampus and cerebellum, tissues where neuronal storage accumulation and cell loss have been seen in the mouse model. The alterations seen in Cln3 mutant mice support the validity of further imaging studies and suggest that this method will have application in assessment of therapeutic approaches in the study of mutant mouse models of NCL including the Cln3 mouse.

Steroid sensitive sites in the avian brain: does the distribution of the estrogen receptor alpha and beta types provide insight into their function?

Studies in avian species have often been useful in elucidating basic concepts relevant to the regulation of reproductive behaviors by sex steroid hormones. Once a link between a steroid hormone and a behavioral response has been established, one can use the localization of steroid hormone receptors in the brain to facilitate the identification of neural circuits that control behavior. The recent identification of a second type of estrogen receptor called estrogen receptor beta or ERbeta has raised new issues about the action of steroid hormones in the brain. A hypothesis has been proposed by Kuiper et al. [1998] based on studies in mammalian species suggesting that ERalpha (the name given to the ER that was previously described) is important for reproduction while ERbeta is more important for non-reproductive functions. In this paper we apply this hypothesis more generally by examining possible functions of ERbeta in avian species. We have initiated studies of the ERbeta in the brain of two avian species, the Japanese quail (Coturnix japonica) and the European starling (Sturnus vulgaris). ERbeta was cloned in both species and the mRNA for this receptor type was localized in the brain employing in situ hybridization histochemistry methods. In both species ERbeta was found to be diffusely present in telencephalic areas consistent with a role for this receptor subtype in cognitive functions. However, ERbeta mRNA was also found in many brain areas that are traditionally thought to be important in the regulation of reproductive functions such as the preoptic region, the bed nucleus of the stria terminalis and the nucleus taeniae. Of the two receptor types, only mRNA for ERalpha was observed in the telencephalic vocal control nucleus HVc of male starlings. Steroid receptors in this nucleus are thought to be an example of an evolutionary specialization that has evolved to coordinate the production of courtship vocalizations with other aspects of reproduction. The lack of ERbeta mRNA expression in HVc is consistent with the hypothesis that ERalpha is preferentially involved in reproductive behaviors while ERbeta is involved in the steroid regulation of other neural functions. However, the widespread occurrence of ERbeta in other nuclei involved in reproductive function suggests that one must be cautious about the general applicability of the above hypothesis until more is known about ERbeta function in these other nuclei.

A mouse model of galactose-induced cataracts

Galactokinase (GK; EC 2.7.1.6) is the first enzyme in the metabolism of galactose. In humans, GK deficiency results in congenital cataracts due to an accumulation of galactitol within the lens. In an attempt to make a galactosemic animal model, we cloned the mouse GK gene (Glk1) and disrupted it by gene targeting. As expected, galactose was very poorly metabolized in GK-deficient mice. In addition, both galactose and galactitol accumulated in tissues of GK-deficient mice. Surprisingly, the GK-deficient animals did not form cataracts even when fed a high galactose diet. However, the introduction of a human aldose reductase transgene into a GK-deficient background resulted in cataract formation within the first postnatal day. This mouse represents the first mouse model for congenital galactosemic cataract.

Structure and expression of a membrane component of the inhibin receptor system

The purification and cloning of a membrane-anchored proteoglycan with affinity for inhibin A are described. Bovine pituitary membranes were isolated, and membrane-anchored proteins were solubilized and used as an enriched source of inhibin binding protein. The extract was passed over an inhibin A affinity column, and a protein, designated p120, was identified as an inhibin-binding moiety. A partial amino acid sequence was determined for the protein, which matched two human complementary DNAs (cDNAs) in the database. The full-length cDNA predicts a 1336-amino acid glycoprotein. Full-length p120-encoding cDNAs were isolated from human testis RNA and cloned into expression vectors. Two p120 messenger RNA transcripts of 4.6 kb and 2 kb are detected in rat pituitary by RNA blot analysis. Similar analysis of rat testis RNA revealed transcripts of identical molecular mass, albeit at lower abundance. To determine the cellular localization of p120 in pituitary and testis, an antibody directed against the predicted extracellular domain of the protein was generated and used in an immunohistochemical analysis of thin tissue sections. p120 immunostaining is coincident with FSHbeta immunopositive gonadotrope cells in rat pituitary. p120 staining is intense in the testicular Leydig cells, which bind iodinated inhibin but not iodinated activin. In summary, an inhibin-binding protein has been isolated that is produced in tissues that are targets of inhibin action.

Differential regulation of pituitary gonadotropin subunit messenger ribonucleic acid levels in photostimulated Siberian hamsters

FSH levels begin to rise 3-5 days after male Siberian hamsters are transferred from inhibitory short photoperiods to stimulatory long photoperiods. In contrast, LH levels do not increase for several weeks. This differential pattern of FSH and LH secretion represents one of the most profound in vivo examples of differential regulation of the gonadotropins. The present study was undertaken to characterize the molecular mechanisms controlling differential FSH and LH synthesis and secretion in photostimulated Siberian hamsters. First, we cloned species-specific cDNAs for the three gonadotropin subunits: the common alpha subunit and the unique FSHbeta and LHbeta subunits. All three subunits share high nucleotide and predicted amino acid sequence identity with the orthologous cDNAs from rats. We then used these new molecular probes to examine the gonadotropin subunit mRNA levels from pituitaries of short-day male hamsters transferred to long days for 2, 5, 7, 10, 15, or 20 days. Short-day (SD) and long-day (LD) controls remained in short and long days, respectively, from the time of weaning. We measured serum FSH and LH levels by RIA. FSHbeta, LHbeta, and alpha subunit mRNA levels were measured from individual pituitaries using a microlysate ribonuclease protection assay. Serum FSH and pituitary FSHbeta mRNA levels changed similarly following long-day transfer. Both were significantly elevated after five long days (2.3- and 3.6-fold, respectively; P < 0.02) and declined thereafter, but they remained above SD control values through 20 long days. Alpha subunit mRNA levels also increased significantly relative to SD control values (maximum 2-fold increase after seven long days; P < 0.03), although to a lesser extent than FSHbeta. Neither serum LH nor pituitary LHbeta mRNA levels changed significantly following long-day transfer. The results indicate that long-day-associated increases in serum FSH levels in Siberian hamsters reflect an underlying increase in pituitary FSHbeta and alpha subunit mRNA accumulation.

Androgen receptor, estrogen receptor alpha, and estrogen receptor beta show distinct patterns of expression in forebrain song control nuclei of European starlings

In songbirds, singing behavior is controlled by a discrete network of interconnected brain nuclei known collectively as the song control system. Both the development of this system and the expression of singing behavior in adulthood are strongly influenced by sex steroid hormones. Although both androgenic and estrogenic steroids have effects, androgen receptors (AR) are more abundantly and widely expressed in song nuclei than are estrogen receptors (ER alpha). The recent cloning of a second form of the estrogen receptor in mammals, ER beta, raises the possibility that a second receptor subtype is present in songbirds and that estrogenic effects in the song system may be mediated via ER beta. We therefore cloned the ER beta complementary DNA (cDNA) from a European starling preoptic area-hypothalamic cDNA library and used in situ hybridization histochemistry to examine its expression in forebrain song nuclei, relative to the expression of AR and ER alpha messenger RNA (mRNA), in the adjacent brain sections. The starling ER beta cDNA has an open reading frame of 1662-bp, predicted to encode a protein of 554 amino acids. This protein shares greater than 70% sequence identity with ER beta in other species. We report that starling ER beta is expressed in a variety of tissues, including brain, pituitary, skeletal muscle, liver, adrenal, kidney, intestine, and ovary. Similar to reports in other songbird species, we detected AR mRNA-containing cells in several song control nuclei, including the high vocal center (HVc), the medial and lateral portions of the magnocellular nucleus of the anterior neostriatum, and the robust nucleus of the archistriatum. We detected ER alpha expression in the medial portion of HVc (also called paraHVc) and along the medial border of the caudal neostriatum. ER beta was not expressed in HVc, in the medial and lateral portions of the magnocellular nucleus of the anterior neostriatum, in the robust nucleus of the archistriatum, or in area X. In contrast, ER beta mRNA-containing cells were detected in the caudomedial neostriatum and medial preoptic area in a pattern reminiscent of P450 aromatase expression in the same brain regions in other songbirds. These data suggest that estrogenic effects on the song system are not mediated via ER beta-producing cells within song nuclei. Nonetheless, the overlapping expression of ER beta- and aromatase-producing cells in the caudomedial neostriatum suggests that locally synthesized estrogens may act via ER beta, in addition to ER alpha, to mediate seasonal or developmental effects on nearby song nuclei (e.g. HVc).

Targeted disruption of the Cln3 gene provides a mouse model for Batten disease. The Batten Mouse Model Consortium [corrected]

Batten disease, a degenerative neurological disorder with juvenile onset, is the most common form of the neuronal ceroid lipofuscinoses. Mutations in the CLN3 gene cause Batten disease. To facilitate studies of Batten disease pathogenesis and treatment, a murine model was created by targeted disruption of the Cln3 gene. Mice homozygous for the disrupted Cln3 allele had a neuronal storage disorder resembling that seen in Batten disease patients: there was widespread and progressive intracellular accumulation of autofluorescent material that by EM displayed a multilamellar rectilinear/fingerprint appearance. Inclusions contained subunit c of mitochondrial ATP synthase. Mutant animals also showed neuropathological abnormalities with loss of certain cortical interneurons and hypertrophy of many interneuron populations in the hippocampus. Finally, as is true in Batten disease patients, there was increased activity in the brain of the lysosomal protease Cln2/TPP-1. Our findings are evidence that the Cln3-deficient mouse provides a valuable model for studying Batten disease.

Proliferative defect and embryonic lethality in mice homozygous for a deletion in the p110alpha subunit of phosphoinositide 3-kinase

Phosphatidylinositol 3,4,5-trisphosphate is a phospholipid signaling molecule involved in many cellular functions including growth factor receptor signaling, cytoskeletal organization, chemotaxis, apoptosis, and protein trafficking. Phosphorylation at the 3 position of the inositol ring is catalyzed by many different 3-kinases (classified as types IA, IB, II, and III), but the physiological roles played by each of the different 3-kinase isozymes during embryonic development and in homeostasis in animals is incompletely understood. Mammalian type IA kinase isozymes are heterodimers that are active at 37 degrees C when the catalytic 110-kDa subunit interacts through an amino-terminal binding domain with a regulatory 85- or 55-kDa subunit. Using gene targeting in embryonic stem cells, we deleted this binding domain in the gene encoding the alpha isoform of the 110-kDa catalytic subunit (Pik3ca) of the alpha isozyme of the type IA kinases, leading to loss of expression of the p110 catalytic subunit. We show that Pik3cadel/del embryos are developmentally delayed at embryonic day (E) 9.5 and die between E9.5 and E10.5. E9. 5 Pik3cadel/del embryos have a profound proliferative defect but no increase in apoptosis. A proliferative defect is supported by the observation that fibroblasts from Pik3cadel/del embryos fail to replicate in Dulbecco's modified Eagle's medium and fetal calf serum, even with supplemental growth factors.

Gold-thioglucose-induced hypothalamic lesions inhibit metabolic modulation of light-induced circadian phase shifts in mice

The circadian clock located in the suprachiasmatic nuclei is entrained by the 24-h variation in light intensity. The clock's responses to light can, however, be reduced when glucose availability is decreased. We tested the hypothesis that the ventromedial hypothalamus, a key area in the integration of metabolic and hormonal signals, mediates the metabolic modulation of circadian responses to light by injecting C57BL/6J mice with gold-thioglucose (0.6 g/kg) which damages glucose-receptive neurons, primarily located in the ventromedial hypothalamus. Light pulses applied during the mid-subjective night induce phase delays in the circadian rhythm of locomotor activity in mice kept in constant darkness. As previously observed, light-induced phase delays were significantly attenuated in fed mice pre-treated with 500 mg/kg i.p. 2-deoxy-D-glucose and in hypoglycemic mice fasted for 30 h, pre-treated with 5 IU/kg s.c. insulin or saline, compared to control mice fed ad libitum. In contrast, similar metabolic challenges in mice with gold-thioglucose-induced hypothalamic lesions did not significantly affect light-induced phase delays compared to mice treated with gold-thioglucose and fed ad libitum. These results indicate that destruction of gold-thioglucose-sensitive neurons in the ventromedial hypothalamus prevent metabolic regulation of circadian responses to light during shortage of glucose availability. Therefore, the ventromedial hypothalamus may be a central site coordinating the metabolic modulation of light-induced phase shifts of the circadian clock.

Photoperiodic effects on gonadotropin-releasing hormone (GnRH) content and the GnRH-immunoreactive neuronal system of male Siberian hamsters

Despite profound photoperiodic differences in circulating gonadotropin levels, consistent differences in the GnRH system have not been observed in Siberian hamsters (Phodopus sungorus) housed chronically in short or long days. During the transition from short to long days, however, male hamsters exhibit a transient increase in the number of cells expressing prepro-GnRH mRNA on the morning of the second long day. Here, we present two experiments designed to examine whether or not this change in mRNA level is associated with changes in GnRH protein synthesis. In the first experiment, we used RIA to measure GnRH content in preoptic area-mediobasal hypothalamic homogenates. We observed a significant increase in GnRH protein levels on the morning of the second long day relative to short- and long-day controls. The latter two groups did not differ from one another. In the second experiment, we used immunocytochemistry to quantify GnRH cell number in the various treatment groups. GnRH-immunoreactive (-ir) cell number did not increase significantly after long-day transfer relative to that in short-day controls; however, both of these groups had significantly more GnRH-ir neurons than long-day controls. We hypothesize that during the transition from short to long days, male Siberian hamsters experience a transient increase in GnRH production in a stable population of neurons. When GnRH secretion subsequently increases on long days, peptide content within neuronal cell bodies declines, leading to a decrease in the number of immunoreactive neurons detected. The rapid response of the hypothalamo-pituitary-gonadal axis in Siberian hamsters to a change in day length defines a narrow temporal window in which to identify the physiological, cellular, and molecular mechanisms mediating the photoperiodic regulation of reproduction.

Lesions of glucose-responsive neurons impair synchronizing effects of calorie restriction in mice

Calorie restriction can induce phase-advances of daily rhythms in rodents exposed to light-dark cycles. To test whether glucose-responsive neurons are involved in the synchronizing effects of calorie restriction, C57BL/6J mice were injected with gold-thioglucose (GTG; 0.6 g/kg) which damages glucose-responsive neurons, primarily located in the ventromedial hypothalamus. From the day of injection, GTG-treated and control mice received a hypocaloric diet (66% of ad libitum food intake) 2 h after lights on. When mice were transferred to constant darkness after 4 weeks and fed ad libitum, the onset of circadian rhythm of locomotor activity was phase-advanced by 1 h in control but not in GTG-treated mice. Therefore, glucose-responsive neurons in the ventromedial hypothalamus may play a role in the synchronizing effects of calorie restriction on circadian rhythmicity.

Age-related changes in the photoperiodic response of Siberian hamsters

Previous studies indicate that as Siberian hamsters (Phodopus sungorus) age, they may lose their ability to show gonadal regression in response to short days. In one study, hamsters that regressed on short days early in life failed to regress when exposed to short days a second time later in life. Thus, Siberian hamsters may experience age-related deficits in photoresponsiveness or may be incapable of regressing twice. In the present study, we attempted to discriminate between these possibilities by examining patterns of gonadal regression in hamsters transferred back and forth from long (16L:8D) to short days (6L:18D) every 6.5, 13, or 26 wk for a 2-yr period. A control group was maintained on long days and had enlarged gonads throughout the entire study. Hamsters alternating between 26 wk of long and short days exhibited complete gonadal regression during their initial but not during their second exposure to short days. Hamsters alternated between long and short days every 13 or 6.5 wk showed regression two to three times, respectively. After about 52 wk of age, the majority of animals in both groups did not regress when exposed to short days. Taken together, the results of this experiment indicate that male Siberian hamsters 1) can exhibit at least two rounds of short-day-induced gonadal regression and 2) fail to regress on short days after about 1 yr of age.

Testis-dependent and -independent effects of photoperiod on volumes of song control nuclei in American tree sparrows (Spizella arborea)

Songbirds exhibit seasonal changes in the volumes of song control nuclei. Birds on long, spring-like days have larger nuclei than do birds on short, winter-like days. The mechanisms mediating volumetric changes have not been determined unequivocally, but testosterone (T) is probably involved. This study examined whether testicular factors are uniquely responsible for seasonal changes in the song system, or whether photoperiod has testis-independent effects. Male American tree sparrows were exposed to one of three photoperiodic conditions: (1) Photosensitive birds were retained on short days (8L:16D). Plasma T is rarely detected in such birds. (2) Photosensitive birds were moved from short days to long days (20L:4D) and photostimulated for three weeks. Photostimulation elevates circulating T in photosensitive birds. (3) Photorefractory birds were held at least four months on 20L:4D. Such birds seldom have detectable levels of T, even though they are on long days. In each condition, there were both intact and castrated birds. Castration typically removes circulating T in tree sparrows. The volumes of the high vocal center (HVC), nucleus robustus archistriatalis (RA), and area X were measured. Song nuclei were largest in intact photostimulated birds. Other long-day birds (i.e. castrated photostimulated, and intact and castrated photorefractory groups) had larger song nuclei than did short-day intact or castrated photosensitive birds and did not differ from each other. These data indicate that photoperiod has both testis-dependent and -independent effects on the volumes of song control nuclei.

Spectrum of mutations in the OCRL1 gene in the Lowe oculocerebrorenal syndrome

The oculocerebrorenal syndrome of Lowe (OCRL) is a multisystem disorder characterized by congenital cataracts, mental retardation, and renal Fanconi syndrome. The OCRL1 gene, which, when mutated, is responsible for OCRL, encodes a 105-kD Golgi protein with phosphatidylinositol (4,5)bisphosphate (PtdIn[4,5]P2) 5-phosphatase activity. We have examined the OCRL1 gene in 12 independent patients with OCRL and have found 11 different mutations. Six were nonsense mutations, and one a deletion of one or two nucleotides that leads to frameshift and premature termination. In one, a 1.2-kb genomic deletion of exon 14 was identified. In four others, missense mutations or the deletion of a single codon were found to involve amino acid residues known to be highly conserved among proteins with PtdIns(4,5)P2 5-phosphatase activity. All patients had markedly reduced PtdIns(4,5)P2 5-phosphatase activity in their fibroblasts, whereas the ocrl1 protein was detectable by immunoblotting in some patients with either missense mutations or a codon deletion but was not detectable in those with premature termination mutations. These results confirm and extend our previous observation that the OCRL phenotype results from loss of function of the ocrl1 protein and that mutations are generally heterogeneous. Missense mutations that abolish enzyme activity but not expression of the protein will be useful for studying structure-function relationships in PtdIns(4,5)P2 5-phosphatases.

Photoperiodic condition modulates the effects of testosterone on song control nuclei volumes in male European starlings

Songbirds possess a specialized network of brain nuclei mediating song learning and production, the song system. In many species, the nuclei in this circuit are larger in volume in males housed on long photoperiods than in males housed on short photoperiods. Exposure to long days initially leads to increases in circulating levels of testosterone (T) and it is generally believed that volume changes in the song system are controlled by T-dependent effects of photoperiod. However, a growing body of evidence indicates that photoperiod can also have T-independent effects on song system morphology. Previous work in our laboratory suggested that photoperiodic condition may modulate the effects of exogenous testosterone on the volumes of song control nuclei in male European starlings (Sturnus vulgaris). In the present report, we tested the hypothesis that photorefractoriness attenuates the effects of T on the volumes of song control nuclei in starlings. One group of long-day photorefractory males (16L:8D) was exposed to exogenous T and two groups of short-day photosensitive birds (8L:16D) were either implanted with T or blank (control) capsules. After 8 weeks, T levels were elevated in both groups of T-implanted birds and were undetectable in control animals. Volumes of the high vocal center were larger in T-implanted photosensitive birds than in both T-implanted photorefractory and control photosensitive males, which did not differ. These results suggest that photorefractoriness renders the song nuclei of starlings less sensitive to stimulatory effects of T. Plasticity in the starling song system appears to require the coordination of the appropriate hormonal milieu with a permissive photoperiodic condition.

Age- and behavior-related variation in volumes of song control nuclei in male European starlings

There is considerable interindividual variation in the volumes of song control nuclei. Sex and physiological condition appear to contribute to these differences; however, these factors alone do not account for all of the variation. Studies have attempted to relate differences in song behavior (i.e., song repertoire size) to variation in song nucleus volume, but have met with mixed success. In this article, two studies are presented that used male European starlings (Sturnus vulgaris) to explore the relationship between song nuclei volumes and age-related differences in song behavior and interindividual variation in song behavior in adults. The results of the first study showed that song repertoire size and song bout length were significantly greater in older adult than in yearling males. In addition, the volumes of the high vocal center (HVC) and nucleus robustus archistriatalis (RA) were significantly larger in older adults than yearlings. Area X of the parolfactory lobe did not differ significantly in volume between the two age classes. In the second study, both HVC and RA volume correlated positively with song bout length but not repertoire size among adult birds. Based on these results a new hypothesis is presented that states that variation in song nuclei volumes in starlings relates more to the amount of song produced than to the number of song types stored in memory.

Two histological markers reveal a similar photoperiodic difference in the volume of the high vocal center in male European starlings

Most studies of seasonal changes in the avian song control system have used Nissl stains to characterize the nuclei. More recent work has indicated that changes in nucleus volume evident in Nissl-stained tissue are not always apparent when investigated with other histochemical criteria. In this experiment, we used two different markers (Nissl stain and alpha 2-adrenergic receptor autoradiography) to characterize changes in the song system of European starlings (Sturnus vulgaris). Fluctuating levels of circulating testosterone (T) appear to be causally related to seasonal changes in the song system. Therefore, we used photoperiod manipulations to place male starlings into different physiological conditions. Photosensitive male starlings were placed on 11L:13D or 16L:8D photoperiods for at least 5 months. Birds on 11L:13D have enlarged gonads and circulating T. In contrast, starlings maintained on 16L:8D initially show marked gonadal growth. However, after about 6-8 weeks the birds are photorefractory (i.e., the gonads are regressed and T falls to undetectable levels). The volume of the high vocal center (HVC) was 44% larger in the 11L:13D than in 16L;8D birds in Nissl-stained tissue. The density of alpha 2-adrenergic receptors as determined by in vitro receptor autoradiography with [3H]p-amino-clonidine (PAC) is higher in HVC than in the surrounding neostriatum, clearly delineating the boundaries of the nucleus. We reconstructed the volume of HVC using PAC stained tissue. Thus, two histochemical markers indicate a photoperiodic difference in HVC volume of male starlings.

Sex differences in the volume of avian song control nuclei: comparative studies and the issue of brain nucleus delineation

Two goals of research on neural sex differences are to establish the behavioral function of such sex differences and to identify precisely what features differ between males and females. Comparative studies of sex differences in the volume of brain nuclei within the songbird vocal control circuit provide one way to address these goals. Informative comparisons can be either inter-specific or intra-specific. Inter-specific comparisons of species within the songbird suborder allow one to establish how species variation in the degree to which there is a sex difference in nuclear volume relates to species variation in the degree to which there is a sex difference in vocal behavior. Intraspecific comparisons of sex differences in nuclear volume involve the comparison of a variety of histochemical methods to define nuclei and describe a nucleus within a species. Sex differences in nuclear volume have now been measured for at least some song control nuclei in 10 different passerine species. In species with more complex male than female song, the volume of key song control nuclei is on average larger in males than in females. However, future studies will require more refined measures of vocal behavior and perceptual abilities to make more precise correlations between brain and behavior. In European starlings (Sturnus vulgaris), the volume of the vocal control nucleus, area X was found to be on average 1.95 times bigger in males than in females based on Nissl stained sections. Variation in neurotransmitter receptor density as determined by quantitative receptor autoradiography can also be used to define clearly the boundaries of a nucleus. When the boundaries of area X in male and female starlings were defined based on variation in muscarinic cholinergic and alpha 2-adrenergic receptor densities, volumetric estimates were obtained that are nearly identical to those obtained with the use of Nissl stains. Intra-specific comparisons of this sort extend our knowledge concerning the neurochemical basis of sex differences in nuclear volume. The wide application of this method would greatly increase our understanding of neural sex differences.

Sexual dimorphism in the volume of song control nuclei in European starlings: assessment by a Nissl stain and autoradiography for muscarinic cholinergic receptors

Previous studies have found that the volume of several song control nuclei is larger in male songbirds than in female songbirds. The degree of this volumetric sex difference within a given species appears to be systematically related to the degree of the behavioral sex difference. The largest volumetric differences have been reported in species in which the male sings and the female sings little, if at all, and the smallest sex differences in volume have been reported in species in which males and females both sing in nearly equal amounts. We compared the volume of three song control nuclei in male and female European starlings (Sturnus vulgaris), a species in which females are known to sing, though at a much lower rate than males. We investigated the volume of hyperstriatum ventrale, pars caudale, nucleus robustus archistriatalis, and area X of the lobus parolfactorius as defined with the use of a Nissl stain. In addition, we measured the volume of area X as defined by the density of muscarinic cholinergic receptors visualized by in vitro receptor autoradiographic methods. The volumes of all three of the song nuclei, as defined by Nissl staining, are significantly larger in males than in females. For area X, Nissl staining and receptor autoradiography indicate the same significant volumetric sex difference. The three nuclei are approximately one and one half to two times larger in males than in females, a degree of dimorphism that is intermediate to those reported for other species. Previous investigations of sex differences in the avian vocal control system have used only Nissl stains to define nuclear volumes. We demonstrate in this paper that receptor autoradiography can be used to assess dimorphisms in nuclear volume. Broad application of this approach to a number of neurotransmitter receptor systems will better characterize the dimorphisms in the song system, and therefore will provide greater insight into the neuroanatomical and neurochemical control of birdsong.

Effect of epidermal growth factor in HLA class I and class II transcription and protein expression in human breast adenocarcinoma cell lines

The spontaneous expression of HLA class I and class II molecules in two human breast carcinoma cell lines (MCF7, T47D) and their modulation during epidermal growth factor treatment are reported. Transcription was analysed by Northern blot and hybridisation with HLA class II and class I cDNA specific probes. The expression of cell surface determinants was examined by internal protein labelling with 35s-methionine, immunoprecipitation with monoclonal antibodies specific for HLA class I or class II, followed by isolation of the immune complex on protein A-Sepharose; at least a quantification of glycoprotein was performed by chromatofocusing. Glycoprotein quantification showed a significant increase of HLA class I and class II (DR) antigen expression after stimulation by epidermal growth factor (0.02 microgram ml-1) in the two cell lines, when compared with untreated cell controls. However, with epidermal growth factor treatment of MCF7 and T47D cells, low increases in the amounts of HLA class I and class II RNA were obtained. These differences between expressed antigens and correspondent RNA amounts would be explained by the fact that EGF in these two cell lines acts more in post-transcription for HLA class I and class II antigens.

Antagonism of prolactin binding by cyclosporine A on MCF7 breast tumour cell line

Cyclosporine A (an immunosuppressive cyclic undercapeptide) acts as an antagonist to prolactin receptors on a breast tumour cell line (MCF7) which is known to express specific prolactin receptors. The competition between cyclosporine A and prolactin to prolactin receptors was demonstrated by measuring the decreased specific 125I-labeled prolactin-binding to prolactin receptors in the presence of increasing concentrations of cyclosporine A. Moreover, cyclosporine A inhibiting effects on the cell growth were investigated in this mammary cancer (MCF) by measuring the cell DNA content with flow cytometry. Our results should prove very useful in understanding the mechanisms of prolactin regulation of DNA synthesis in tumorigenesis of the mammary gland.

Genotypic analyses of Richter's syndrome

The authors report the immunogenotype of two cases of Richter's syndrome. The immunoglobulin gene rearrangement pattern obtained on Southern Blot analysis was found in both cases to be the same in leukemic blood cells and in the tissue involved by the lymphoma. The beta chain and gamma chain T-cell receptor gene rearrangement pattern exhibited a germ-line configuration in the peripheral blood cells and in the lymph node in Case 2, whereas in Case 1 the lymph node had a gene rearrangement in the beta chain, as well as in the gamma chain T-cell receptor, and the leukemic cells from bone marrow were found to be in a germ-line configuration for T-cell receptors (beta and gamma chains).

Genotypic analyses of Hodgkin's disease

In spite of the use of molecular biology, the cellular lineage and clonality of Reed-Sternberg cells, the abnormal cells of Hodgkin's disease, remain an enigma. We studied the pattern of rearrangements at immunoglobulin and T-cell receptor loci in 23 patients suffering from Hodgkin's disease. Two out of 23 patients exhibited immunoglobulin gene rearrangements. No rearrangements of the T-cell receptor beta-chain gene were detected in any patient examined. Our results showed no correlation between the presence of rearranged bands and the number of Reed-Sternberg cells.

Presence of reverse transcriptase in human leukemias and lymphomas

Reverse transcriptase (RT) transcribes viral RNA into DNA to be integrated into the host genome. To study epidemiological aspects of human leukemias and lymphomas which are known to express retroviruses, clinical specimens in this report were assayed for divalent cation-dependent viral-specific RT. The assay was carried out with cells solubilized with a detergent to release RT enzyme. RT was purified with poly(U)-Sepharose which fixed all DNA polymerases and assayed with 4 synthetic homopolymers, oligonucleotide primed-templates, poly(rA)-oligo(dT)12-18 or poly(dA)-oligo(dT)12-18 with Mg2+, poly(rC)-oligo(dG)12-18 or poly(rCm)-oligo(dG)12-18 with Mn2+ as divalent cation and [methyl-3H]thymidine 5'-triphosphate or deoxy[8-3H]guanosine 5-triphosphate respectively. Radioactivity incorporation of the precipitate allows quantitation of RT activity. One Hodgkin's disease, one out of 2 B lymphomas, one out of 2 T lymphomas, eight out of 12 leukemias were found to be positive for RT activity as well as acquired immunodeficiency syndrome (AIDS) patients, known to express RT. The obtained RT activity in hematological malignancies was found to be comparable to positive controls such as RT enzymes purified from avian myeloblastosis and Moloney murine leukemia viruses.

Effects of cyclosporine A on Ia antigen expression in N-nitroso-N-methylurea-induced rat mammary tumors

Cyclosporine A (an immunosuppressive agent) decreases Ia lymphoid differentiation marker in female Sprague-Dawley rats with N-nitroso-N-methylurea-induced mammary tumors. Presence of lymphoid differentiation antigens was determined on mammary tumor cells and lymphoid cells from bone marrow, spleen, and peripheral blood by flow cytometric analysis. Quantification of Ia antigen expression was also performed by affinity chromatography and chromatofocusing in mammary tumors. A significant decrease in Ia antigen expression by mammary tumors of animals treated with cyclosporine A was noted with the two different methods. Cyclosporine A acts as an antagonist to prolactin receptors in such hormone-dependent mammary cancer. Our results should prove very useful in understanding the mechanisms of prolactin regulation of Ia antigen in tumorigenesis of the mammary gland.

Immunohistochemical evaluation of reverse transcriptase in breast carcinoma with polyclonal antibodies raised in rabbit

In this study, the presence of reverse transcriptase in breast tumours was examined with immunoperoxidase staining using antibodies raised in rabbit against reverse transcriptase of Moloney murine leukemia virus and against reverse transcriptase of avian myeloblastosis virus. The specificity of such antibodies was investigated with ELISA and Western blotting techniques. Five cases of infiltrating ductal carcinomas were found positive with the immune serum anti-reverse transcriptase of Moloney murine leukemia virus on 28 studied infiltrating ductal carcinomas, 2 infiltrating lobular carcinomas and 2 fibroadenomas.

Ovarian hormones, antiestrogen and pregnancy effects on the expression of class II histocompatibility antigens by N-nitroso-N-methylurea-induced rat mammary carcinomas

Hormonal modulation of Class II histocompatibility antigen expression was studied in female Sprague-Dawley rats with N-nitroso-N-methylurea-induced mammary tumors. The effects of ovarian hormones, pregnancy and lactation were examined when cancers appeared. At this time, rats with tumors were divided into several groups. Different groups received respectively 17 beta-estradiol alone, 17 beta-estradiol in association with progesterone, and tamoxifen alone. Other groups were selected to undergo pregnancy. The control group received carcinogenic treatment only. For all removed tumors, Class II histocompatibility antigens were radiolabeled, specifically immunoprecipitated with monoclonal antibody and quantified by chromatofocusing. The amount of Class II histocompatibility antigens measured in NMU-induced rat mammary tumors without any hormonal treatment decreased significantly after treatment with estrogen alone or in association with antiestrogen and during the pregnancy. Nevertheless, Class II histocompatibility antigen expression was not changed in mammary carcinoma from rats receiving progesterone, but increased significantly during the lactation. These results demonstrated clearly that ovarian hormones change the Class II histocompatibility antigen expression of NMU-induced mammary tumors in female Sprague-Dawley rats.

Detection of reverse transcriptase activity in human breast tumors

The function of reverse transcriptase (RT) in retroviruses is to copy their RNA genomes in DNA to be integrated into the host genome. We report a high purity preparation of this enzyme by adsorption onto poly(U)-sepharose. We analyzed RT activity with poly(rA)--oligo (dT)12-18, poly(dA)--oligo (dT)12-18, poly(rC)--oligo (dG)12-18 and poly(rCm)--oligo (dG)12-18 to obtain a more accurate pattern of RT. 8 out of 16 malignant breast samples were positive for RT activity, more specifically with poly(rC)--oligo (dG)12-18 and poly(rCm)--oligo (dG)12-18. The 5 non-malignant mammary samples tested were negative for RT activity. Assays with poly(rC)--oligo (dG)12-18 and poly(rCm)--oligo (dG)12-18. The 5 non- malignant mammary samples tested were negative for RT activity. Assays with N--nitroso--N--methylurea--induced rat mammary carcinomas were negative for RT activity.

Effects of N-nitroso-N-methylurea on mammary and pituitary glands of young female Sprague-Dawley rats

Female Sprague-Dawley rats aged 50 days received 3 intravenous injections of N-nitroso-N-methylurea, 5 mg/100 g of body weight at 4 weekly intervals. When the first palpable mammary tumours appeared, with an incidence of 50 to 60% after the third injection, rats were randomized into 8 groups: group 1 was treated with 17 beta-estradiol; group 2 received progesterone; group 3 received in association 17 beta-estradiol + progesterone; group 4 was treated with tamoxifen. In group 5, rats received ovine prolactin. In groups 6 and 7, female rats were bred. Group 8, as a control group, received no hormonal treatment. Other control groups of 8 rats aged 140 days were made up of rats receiving 17 beta-estradiol alone (group 9) and rats receiving only ovine prolactin (group 10). The last group was kept without any treatment (group 11). The incidence of mammary tumours was followed in groups 1 to 8. All pituitary glands and mammary tumours were removed and weighed when rats were sacrificed after the last hormonal injection in each group. Light microscopy allowed the anatomopathologist to classify all removed mammary tumours in each group as adenocarcinoma. Light and electron microscopies with all pituitary glands in groups 1 to 11 showed no abnormality. The distribution of the pituitary weights was between 4.0 to 6.8 mg per 100 g of body weight. No adenomas were detected in the pituitary glands of the 5-month-old Sprague-Dawley rats receiving N-nitroso-N-methylurea.

Effect of Purkinje cell loss on cerebellar gangliosides in nervous mutant mice

The distribution of cerebellar gangliosides was studied in adult (73 +/- 2 days) nervous (nr/nr) mutant mice which lose 50-90% of their Purkinje cells. This neuronal loss is associated with significant reductions in cerebellar weight and ganglioside concentration. The cerebellar dry weights (mg) and the ganglioside concentrations (microgram N-acetylneuraminic acid per 100 mg dry weight) in nr/nr mice and age-matched normal littermates (+/?) are 7.4 +/- 0.3 mg and 13.2 +/- 0.4 mg; and 411.7 +/- 4.8 micrograms and 438.5 +/- 2.1 micrograms, respectively. Abnormalities were also observed for the concentration of certain ganglioside species. Most notably, GT1a is significantly reduced by 42%, and GD3 is significantly increased by 29% in the nr/nr mice compared to the +/? mice. The nr/nr mice also express a slight but significant reduction in GT1b. No ganglioside abnormalities were observed between the nr/nr and +/? mice in cerebral cortex. We previously found reduced cerebellar GT1a content in other mutants that also lose Purkinje cells, i.e., sg/sg, pcd/pcd, and Lc/+. GT1a is not reduced, however, in wv/wv mice that lose mostly granule cells. The findings in nr/nr mice are therefore consistent with our hypothesis that GT1a is enriched in Purkinje cells. GD1a, which is enriched in mature granule cells, is not reduced in the nr/nr mice.(ABSTRACT TRUNCATED AT 250 WORDS)

N-nitroso-N-methylurea-induced mammary carcinogenesis: effect of prolactin on expression of Ia antigen by tumor cells

Prolactin (PRL) increases of Ia antigen (Ia Ag) expression in female Sprague-Dawley rats with N-nitroso-N-methylurea [(NMU) CAS: 684-93-5]-induced mammary tumors were studied. The effectiveness of PRL was examined when cancers appeared about 2-3 months after the first NMU administration. Rats with NMU-induced mammary tumors were divided into 3 groups: Group 1 was treated with 30 micrograms ovine PRL (o-PRL) in daily sc injections for 5 days. Group 2 received 0.5 mg 2 alpha-bromoergocryptine (CB-154), a known inhibitor of pituitary gland secretion, daily in sc injections for 6 days. Group 3 was the control group. Ia Ags expressed by NMU-induced mammary tumor cells were then quantified successively by double labeling [protein membrane cells with iodine-131 and anti-Ia monoclonal antibody (MoAb) with iodine-125]; then isolation and quantification of the doubly labeled immune complex were performed by affinity chromatography and chromatofocusing successively. When the specific activity of glycoproteins is known, the amount of glycoproteins that bind specifically to the anti-Ia MoAb can be deduced. In NMU-induced rat mammary tumor controls, about 5% of the purified glycoproteins bound specifically to the MoAb, and the amount increased to 8% for NMU-induced rat mammary tumors treated with 30 micrograms o-PRL daily for 5 days and decreased to 2.5% in NMU-induced rat mammary tumors treated with 0.5 mg CB-154 daily for 6 days. Total PRL receptor levels were measured in all tumors tested. For control NMU-induced rat mammary tumors, total PRL receptor levels were 6.35 +/- 1.40 fmol/mg protein, 7.20 +/- 2.40 fmol/mg protein for NMU-induced rat mammary tumors treated with o-PRL, and 6.81 +/- 2.34 fmol/mg protein for NMU-induced rat mammary tumors treated with CB-154. Our results demonstrated that treatment of NMU-induced rat mammary tumors with PRL increased the amount of Ia Ag expression by tumor cells and should prove very useful to the understanding of the biology of PRL in the tumorogenesis of the mammary gland.

Calcium ATPase activities in synaptic plasma membranes of seizure-prone mice

Audiogenic seizure (AGS)-susceptible DBA/2 (D2) mice have a significant reduction in brain Ca2+-ATPase activity compared to AGS-resistant C57BL/6 (B6) mice. This reduction is inherited together with AGS susceptibility in B6 X D2 recombinant inbred strains. The Ca2+-ATPase reduction occurs in microsomes and synaptosomes, but not in mitochondria. This enzyme activity is measured at a high Ca2+ concentration (2 mM) with no added Mg2+ or EGTA. We further studied this Ca2+-ATPase activity and a Mg2+-dependent (Ca2+ + Mg2+)-ATPase activity in synaptic plasma membranes (SPM) from the B6 and D2 strains. Using EGTA or CDTA to adjust free Ca2+ concentrations, we measured Ca2+-ATPase activities at Ca2+ concentrations from 0.8 microM to 436 microM. The Ca2+-ATPase activity is consistently lower in the D2 than in the B6 SPM over all Ca2+ concentrations. The basal Mg2+-ATPase activity measured at 2 mM MgCl2, is also lower in SPM of D2 than B6 mice. Calcium stimulates the basal Mg2+-ATPase activity to the same extent in the SPM of the B6 and the D2 mice. Maximum stimulation in both strains occurs at 150 microM added CaCl2 (buffered with 100 microM EGTA). Higher Ca2+ concentrations inhibit this ATPase activity similarly in both strains. The EGTA-EDTA washing of SPM significantly reduces by 50% of the (Ca2+ + Mg2+)-ATPase activities of both strains, whereas calmodulin treatment restored these activities. Neither of these treatments, however, has any noticeable effects on the Ca2+-ATPase activities of the strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of prolactin on class II HLA antigen expression by MCF7 cell line

Effects of prolactin on Class II HLA Ag expression have been identified for the first time in a human breast cancer cell line maintained in long-term tissue culture (MCF7) and were reported in this work as follows. Quantification methods for assaying Class II HLA Ag expression modulated by prolactin were established. Class II HLA Ags were internally labelled with [35S] methionine, extracted with Nonidet P-40, immunoprecipitated specifically with anti-Class II HLA MoAbs, isolated on protein A-Sepharose and quantified by chromatofocusing. For low doses of prolactin added to a final concentration (0.015 to 0.350 micrograms/ml culture medium), no change in Class II HLA Ags expressed by MCF7 cells was observed, when compared with controls, the percent of Class II HLA Ags assayed by chromatofocusing was then 4.03 +/- 0.57. For high doses of prolactin added to the final concentration (1.50 micrograms to 3.00 micrograms/ml medium), the percent of Class II HLA Ags increased to 6.05 +/- 0.72. When prolactin was added to the culture medium of MCF7 human breast cancer cell line, increased Class II HLA Ag expression by membrane cells was noted. Prolactin induction of Class II HLA Ag expression by human breast cancer cell lines should prove very useful to study the biology of prolactin in the tumorogenesis of the human breast.

Comparison of Class II HLA antigen expression in normal and carcinomatous human breast cells

Class II HLA antigen expression in breast carcinoma and normal breast gland cells was compared using a method more accurate than immunofluorescence. This new method involves labeling membrane proteins with 131I and the anti-Class II HLA monoclonal antibody with 125I. The isolation and purification of the doubly labeled (125I-131I) immune complex was performed by affinity chromatography and chromatofocusing successively. When the specific activity of glycoproteins is known, the amount of glycoproteins which bind specifically to the anti-Class II HLA monoclonal antibody can be deduced. In breast carcinoma cells, 1.5 to 2% of the purified glycoproteins bind specifically to the monoclonal antibody, whereas less than 0.3% of normal breast gland cells binds. In contrast, leukemic cells, of which 80 to 90% possess Class II HLA antigens, 2 to 3% of Class II HLA glycoproteins bind specifically with the anti-Class II HLA monoclonal antibody.

Cellular distribution of gangliosides in the developing mouse cerebellum: analysis using the staggerer mutant

The distribution of cerebellar gangliosides was studied in staggerer (sg/sg) mutant mice, where the majority of granule cells die after completing their migration across the molecular layer. In addition, the external granule cell layer in sg/sg mice persists longer than in normal mice. Moreover, in the sg/sg cerebellum, Purkinje cells are significantly reduced in number, and almost none have tertiary branchlet spines. The loss of Purkinje cells and granule cells in sg/sg mice is accompanied by an early-onset reactive gliosis that continues through adulthood. By correlating changes in ganglioside composition with the well-documented histological events of cerebellar development in normal and sg/sg mice, we obtained strong evidence for a nonrandom cellular distribution of gangliosides. The sharpest reduction in the GD1a content of sg/sg cerebellum occurred after 15 days of age, coincident with granule cell loss. GT1a, on the other hand, was significantly reduced from 15 through 150 days in the sg/sg mice. GD3 is a major ganglioside of the undifferentiated granule cell, but it becomes rapidly displaced by the more complex gangliosides with the onset of granule cell maturation. In the sg/sg mice, GD3 persisted at abnormally high levels from 15 to 28 days and then accumulated through adulthood. These findings, and those from other cerebellar mouse mutants, suggest that GD1a is enriched in granule cells and that GT1a is enriched in Purkinje cells. Our findings also suggest that GT1a is more concentrated in branchlet spines than in other regions of the Purkinje cell membrane. GT1b appears to be enriched in both granule cells and Purkinje cells, whereas GM1 appears to be enriched in myelin. Furthermore, the apparent persistence of the embryonic ganglioside GD3 in sg/sg mice results from an early-onset reactive gliosis, together with a partial retardation in granule cell maturation. The accumulation of GD3 beyond 28 days reflects the continued accretion of GD3 in reactive glia.