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Search for other papers by HELEN M. MURPHY in
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SUMMARY
Hypocalcaemia resulted from the injection of grey-lethal mouse plasma into assay mice. On bioassay, parallelism in dose—response curves was established between this factor, MRC research standard calcitonin and acid extracts from the grey-lethal mouse thyroid gland. Other lines of evidence, i.e. stability at neutral and acid pH's after ultracentrifugation for long periods, after adsorption on to silica gel and the results of enzymic and acid hydrolysis, suggest that the hypocalcaemic factor is a small polypeptide. Since a hypersecretion of calcitonin could account for most of the findings in the osteopetrosis of the grey-lethal mouse it is tentatively proposed that the hypocalcaemic factor is this hormone.
Search for other papers by J. J. STERN in
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Search for other papers by M. MURPHY in
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SUMMARY
The wheel-running activity of 19 male rats was examined before and after castration. Castration significantly reduced spontaneous activity. Testosterone propionate (TP) administration increased activity to levels before castration. Cyproterone acetate given with TP did not inhibit the increase in activity but inhibited the growth of seminal vesicles.
Search for other papers by M. REISS in
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Search for other papers by R. E. HEMPHILL in
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Search for other papers by B. M. MURPHY in
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Search for other papers by J. M. HALKERSTON in
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Search for other papers by F. E. BADRICK in
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Tracer methods with radioactive iodine have been employed in recent years to assess human thyroid function. Some authors measured the uptake of I131 by the thyroid, [Hamilton & Soley, 1940; Hertz, Roberts & Salter, 1942; Rawson, Evans, Means, Peacock, Lerman & Cortell, 1944; and others]: other authors measured the excretion [Hamilton & Soley, 1939; Keating, Power, Berkson & Haines, 1947; Skanse, 1948; and others]. Extensive investigations have been carried out with the help of radioactive iodine on the iodine metabolism in the thyroid function of animals (recently reviewed by Rawson & McArthur [1947]; Chaikoff & Taurog [1948] and Hevesy [1948]). The results of these experiments have so far been utilized only in a very restricted way for diagnostic purposes on human patients.
Although various tracer doses, with and without carrier, have been used, up to the present no standardized routine method for the investigation of patients has been developed.
Search for other papers by B. G. MILLER in
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Search for other papers by LEIGH MURPHY in
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Search for other papers by G. M. STONE in
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SUMMARY
The concentrations of soluble oestradiol and progesterone receptor proteins and several metabolic activities were measured in the genital tracts of ewes killed on Days 0 (oestrus), 2, 5, 10 or 14 of the oestrous cycle. In caruncular endometrium and in whole uterus the concentrations of oestradiol receptor (pmol steroid bound/mg tissue DNA) were highest at oestrus and declined steadily thereafter to minimal values at Day 14. The concentrations of progesterone receptor were highest on Days 0–5, then declined to low levels on Days 10–14. There was little metabolism of either [3H]oestradiol or [3H]progesterone in minces of whole uterus and with either steroid the pattern of metabolism did not change at any stage of the cycle. The in-vivo rates of synthesis of protein in caruncular endometrium and in isthmic oviduct were highest at or shortly after oestrus (Days 0–2), then declined to low levels on Days 10–14. RNA:DNA ratios in these two tissues were also greatest at oestrus and subsequently fell to minimal values by Day 14. The results are discussed in relation to ovarian secretion of oestradiol and progesterone during the oestrous cycle of the ewe.
Search for other papers by Greg M Kowalski in
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Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, USA
Search for other papers by Michael J Kraakman in
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Search for other papers by Shaun A Mason in
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Search for other papers by Andrew J Murphy in
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Search for other papers by Clinton R Bruce in
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The high-fat, high-sucrose diet (HFSD)–fed C57Bl/6 mouse is a widely used model of prediabetes. However, studies typically implement a relatively short dietary intervention lasting between 4 and 16 weeks; as a result, little is known about how a long-term HFSD influences the metabolic profile of these mice. Therefore, the aim of this investigation was to examine the effects of consuming a HFSD for 42 weeks on the development of hyperinsulinaemia and glucose intolerance in male C57Bl/6 mice. Two cohorts of HFSD mice were studied at independent institutes and they underwent an oral glucose tolerance test (OGTT) with measures of plasma insulin and free fatty acids (FFA). Age-matched chow-fed control mice were also studied. The HFSD-fed mice were hyperinsulinaemic and grossly obese, being over 25 g heavier than chow-fed mice, which was due to a marked expansion of subcutaneous adipose tissue. This was associated with a 3-fold increase in liver lipid content. Glucose tolerance, however, was either the same or better than control mice due to the preservation of glucose disposal as revealed by a dynamic stable isotope-labelled OGTT. In addition, plasma FFAs were suppressed to lower levels in HFSD mice during the OGTT. In conclusion, we have made the paradoxical observation that long-term HFSD feeding results in the resolution of glucose intolerance in the C57Bl/6 mouse. Mechanistically, we propose that the gross expansion of subcutaneous adipose tissue increases the glucose disposal capacity of the HFSD-fed mouse, which overcomes the prevailing insulin resistance to improve glucose tolerance.
Search for other papers by Jinwon Eo in
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Search for other papers by Kyuyong Han in
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Department of Biomedical Science and Technology, Department of Pathology and Immunology, Howard Hughes Medical Institute, Laboratory of Reproductive Biology and Infertility, RCTC, IBST, Konkuk University, 1 Hwayang-Dong, Kwangjin-Gu, Seoul 143-701, South Korea
Search for other papers by Kenneth M Murphy in
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Search for other papers by Haengseok Song in
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Search for other papers by Hyunjung Jade Lim in
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Etv4, Etv1, and Etv5 are members of Etv4 subfamily of E26 transformation-specific (Ets) transcription factors that are known to influence a host of biological processes. We previously showed that Etv5, expressed in Sertoli cells, plays a crucial role in maintaining spermatogonial stem cell niche in the mouse testis. However, it is not yet known whether Etv4 family members are expressed in the ovary or play any role in ovarian functions. Here, we show that Etv5 and Etv4 are expressed in mouse ovaries in granulosa and cumulus cells during folliculogenesis. Both Etv5 and Etv4 mRNAs are also detected in cumulus–oocyte complexes (COCs) and denuded oocytes. Notably, Etv4 is highly expressed in the cumulus cells of ovulated COCs at 16-h post-human chorionic gonadotropin. Cyclooxygenase-2 (PTGS2), a rate-limiting enzyme for prostaglandin synthesis, is critical for oocyte maturation and ovulation. Since several putative Ets-binding sites are present in the PTGS2 promoter, we examined whether Etv5 influences Ptgs2 transcriptional activity. Indeed, we found that addition of Etv5 increases the transcriptional activity of the 3.2-kb mouse Ptgs2 promoter by 2.5-fold in luciferase reporter assays. Collectively, the results show that Etv4 and Etv5 are expressed in granulosa and cumulus cells during folliculogenesis and ovulation, suggesting that they influence cellular events in the ovary by regulating downstream genes such as Ptgs2.
Search for other papers by KG Murphy in
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Search for other papers by CR Abbott in
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Search for other papers by M Mahmoudi in
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Search for other papers by R Hunter in
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Search for other papers by JV Gardiner in
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Search for other papers by M Rossi in
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Search for other papers by SA Stanley in
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Search for other papers by MA Ghatei in
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Search for other papers by MJ Kuhar in
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Search for other papers by SR Bloom in
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The distribution of cocaine- and amphetamine-regulated transcript peptide (79-102)-like immunoreactivity (CART-LI) was quantified in brain and peripheral tissues of male and female Wistar rats, and male obese (fa/fa) and heterozygous (Fa/+) Zucker rats using a specific RIA. CART-LI tissue levels have not been quantified previously. The assay, using cocaine- and amphetamine-regulated transcript (CART) (79-102) as a standard and radioactive tracer and an antibody to CART (79-102) fragment, detected CART-LI in all brain regions examined, the anterior and posterior pituitary, the spinal cord and throughout the gastrointestinal tract of both male and female Wistar rats. The highest concentrations were found in the hypothalamus, duodenum, anterior pituitary and posterior pituitary (50.6+/-4.4, 26.1+/-4.2, 50.0+/-1.3 and 373.0+/-55.2 pmol/g wet tissue respectively, means+/- s.e.m., n=6-10 male animals). There was no significant variation between the sexes. The concentrations of CART-LI in hypothalami and anterior and posterior pituitaries from fa/fa rats were significantly (P<0002) lower than those of Fa/+ controls (35.9+/-2.1 vs 53.9+/-4.9,<0.6 vs 1.8+/-0.4 and 114+/-9.1 vs 255.5+/- 20.9 pmol/g wet tissue respectively, means+/- s.e.m., n=7). Gel permeation chromatography of regions of rat brain and gastrointestinal tract showed possible differential processing between regions. CART-LI was released from hypothalamic tissue slices in a calcium-dependent fashion by potassium-induced depolarisation. Northern blot analysis detected CART mRNA in the hypothalamus, anterior pituitary, brain stem, cerebellum and spinal cord. The pattern o! f distribution of CART mRNA and CART-LI in various neural and other tissues is in accord with a role for CART as a neurotransmitter.
Search for other papers by C Chakraborty in
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Search for other papers by S Sharma in
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Search for other papers by N Katsumata in
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Search for other papers by L J Murphy in
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Search for other papers by I C Schroedter in
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Search for other papers by M C Robertson in
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Search for other papers by R P C Shiu in
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Search for other papers by H G Friesen in
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Abstract
The secretion of peptide 23 by rat pituitary cells is stimulated by growth hormone-releasing hormone and inhibited by somatostatin. Recent cloning of the cognate cDNA for peptide 23 revealed that it is identical to pancreatitis-associated protein (PAP). In the present study, the clearance and tissue uptake of recombinant peptide 23/PAP in normal adult male rats was assessed. The plasma half-life of recombinant peptide 23/PAP was 4·8 ±1·4 (s.d.) min. Maximal accumulation of radiolabelled peptide 23/PAP was observed in the kidney, stomach, small intestine and pancreas whereas negligible uptake was seen in the liver, lung or heart. Peptide 23/PAP was detected in a variety of tissue extracts using a radioimmunoassay. Extracts of ileum contained the highest concentrations of peptide 23/PAP. In situ hybridization analysis showed that peptide 23/PAP mRNA was highly expressed in the columnar epithelial cells of ileum, jejunum and duodenum. These observations demonstrate that peptide 23/PAP, a protein previously thought to be of pituitary origin, is widely expressed in the gastrointestinal tract and that it is rapidly removed from the circulation by the kidney and by tissues which express peptide 23/PAP.
Journal of Endocrinology (1995) 145, 461–469
Search for other papers by H-L Ang in
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Search for other papers by R Ivell in
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Search for other papers by N Walther in
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Search for other papers by H Nicholson in
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Search for other papers by H Ungefroren in
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Search for other papers by M Millar in
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Search for other papers by D Carter in
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Search for other papers by D Murphy in
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Abstract
The bovine oxytocin gene has been expressed in the testes of two independent transgenic mouse lines. Hybridization and RNase protection analysis showed that the oxytocin transgene was transcribed from the normal functional promoter in the Sertoli cells of the seminiferous tubules in a developmentally regulated manner. Immunohistochemistry indicated that both oxytocin and neurophysin epitopes were expressed together in the Sertoli cells at stages I–V and X–XII of the cycle of the seminiferous epithelium. Furthermore, analysis with high- performance liquid chromatography showed that there was a tenfold increase in the amount of amidated oxytocin present in testicular extracts from the transgenic mice. However, there appeared to be no detectable effect of this overproduction of hormone on testicular morphology or fertility parameters. A significant decrease by 50% was detected only in the levels of intratesticular testosterone and dihydrotestosterone. The results point to a local paracrine role for oxytocin in the modulation of Leydig cell function.
Journal of Endocrinology (1994) 140, 53–62
Search for other papers by B M McGowan in
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Search for other papers by J S Minnion in
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Search for other papers by K G Murphy in
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Search for other papers by S A Stanley in
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Search for other papers by W S Dhillo in
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Search for other papers by J V Gardiner in
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Search for other papers by M A Ghatei in
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Search for other papers by S R Bloom in
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Relaxin-3 is a member of the insulin superfamily. It is expressed in the nucleus incertus of the brainstem, which has projections to the hypothalamus. Relaxin-3 binds with high affinity to RXFP1 and RXFP3. RXFP3 is expressed within the hypothalamic paraventricular nucleus (PVN), an area central to the stress response. The physiological function of relaxin-3 is unknown but previous work suggests a role in appetite control, stimulation of the hypothalamic–pituitary–gonadal axis and stress. Central administration of relaxin-3 induces c-fos expression in the PVN and increases plasma ACTH levels in rats. The aim of this study was to investigate the effect of central administration of human relaxin-3 (H3) on the hypothalamic–pituitary–adrenal (HPA) axis in male rodents in vivo and in vitro. Intracerebroventricular (i.c.v) administration of H3 (5 nmol) significantly increased plasma corticosterone at 30 min following injection compared with vehicle. Intra-PVN administration of H3 (1.8–1620 pmol) significantly increased plasma ACTH at 1620 pmol H3 and corticosterone at 180–1620 pmol H3 at 30 min following injection compared with vehicle. The stress hormone prolactin was also significantly raised at 15 min post-injection compared with vehicle. Treatment of hypothalamic explants with H3 (10–1000 nM) stimulated the release of corticotrophin-releasing hormone (CRH) and arginine vasopressin (AVP), but H3 had no effect on the release of ACTH from in vitro pituitary fragments. These results suggest that relaxin-3 may regulate the HPA axis, via hypothalamic CRH and AVP neurons. Relaxin-3 may act as a central signal linking nutritional status, reproductive function and stress.
