Endocrinology.
Publisher:
Association for the Study of Internal Secretions,. New York : Oxford University Press (2017)
Frequency: Monthly
Country: United States
Language: English
Author(s):
Association for the Study of Internal Secretions (U.S.), Endocrine Society.
Start Year:1917 -
ISSN:
0013-7227 (Print)
1945-7170 (Electronic)
0013-7227 (Linking)
1945-7170 (Electronic)
0013-7227 (Linking)
Impact Factor
4.8
2022
| NLM ID: | 0375040 |
| (DNLM): | E07180000(s) |
| (OCoLC): | 01567879 |
| Coden: | ENDOAO |
| LCCN: | sg 39000030 |
| Classification: | W1 EN396S |
Spontaneous and stimulated adrenocorticotropin and vasopressin pulsatile secretion in the pituitary venous effluent of the horse. Plasma ACTH, arginine vasopressin (AVP), and catecholamines were measured at 5-min intervals in the pituitary venous effluent of the unanesthetized horse. Pulses of ACTH and AVP were found to be surprisingly brief (usually of less than 10-min duration) and frequent (averaging between 15-25 min). A highly significant relationship in the changes in concentration of these two hormones was demonstrated (P less than 0.0002) both at rest and after a mild hypoglycemic stimulus. Although there was also a significant correlation (P less than 0.005) between simultaneous plasma ACTH and AVP values the pu...
Gas chromatography-mass spectrometry of androgens in equine ovarian follicles at ultrastructurally defined stages of development. Identification of 19-nortestosterone in follicular fluid. Follicular fluid was obtained from equine follicles at different stages of development as determined by ultrastructural study. Gas chromatography-mass spectrometry associated with stable isotope dilution permitted the demonstration of high levels of 4-estrene-3,7-dione and 17 beta-hydroxy-4-estren-3-one, 17 beta-hydroxy-4-estren-3-one levels often being about 10 times higher than those of testosterone. These findings suggest that in the mare ovary, an aromatizing pathway may proceed using these 19-norsteroids as intermediates. As a consequence of this high level of 19-norsteroids, testosterone...
Concentration increase of unbound testosterone in plasma of the mare throughout pregnancy. Blood testosterone levels were measured by RIA and gas chromatography-mass spectrometry in the pregnant mare. They were found to increase from the very beginning of pregnancy, reaching peak values 10 times higher than the basal values at the seventh month and then to return to basal values by the week after parturition. Testosterone binding by plasma proteins was investigated in nonpregnant and pregnant mares throughout gestation. Equilibrium dialysis and gel equilibration methods did not reveal any blood specific testosterone-binding activity at any gestational stage. Hence, blood testosteron...
Endocrine aspects of early pregnancy in pony mares: a comparison of uterine luminal and peripheral plasma levels of steroids during the estrous cycle and early pregnancy. Comparisons of estrone, 17 beta-estradiol, and plasma progestin concentrations were made in uterine fluid and peripheral blood of nonpregnant and pregnant pony mares. Concentrations of these steroids were also measured within yolk sac fluid from blastocysts on days 12, 14, 16, and 18 of pregnancy to obtain more complete analyses of the uterine environment (uterine fluid plus yolk sac fluid) of early pregnancy. Thirty mares were randomly assigned to six treatment groups (n = 5/group), and uterine fluid and peripheral blood samples were obtained on days 8, 12, 14, 16, 18, and 20 postovulation. A...
Difference in sizes of human compared to murine alpha-subunits of the glycoprotein hormones arises by four-codon gene deletion or insertion. The sizes of the human and subhuman alpha-subunits of the glycoprotein hormones differ by four amino acids (hCG alpha, 92 amino acids; murine, equine, bovine, and ovine alpha, 96 amino acids). The shortening of the human alpha-subunit has been attributed to posttranslational proteolysis. We have recently determined the nucleotide sequences of the mRNAs encoding the precursors of the alpha-subunit of mouse TSH and rat gonadotropins using recombinant DNA techniques. In this report, we have compared these nucleotide sequences and their deduced amino acid sequences with those of the pre- alpha-sub...
Bioactive and immunoreactive adrenocorticotropin in normal equine pituitary and in pituitary tumors of horses with Cushing’s disease. Equine Cushing's disease is caused by hypersecretion of ACTH by hyperplasia or adenomas of pars intermedia (PI) cells, in contrast to human Cushing's disease, which is caused by hyperplasia or adenomas of pars distalis (PD) ACTH-secreting cells. We assayed both bioactive and immunoreactive (IR) ACTH in two normal equine pituitary glands and in the PD, PI, and pars nervosa of four such glands, as well as in the PI adenomas of five horses with Cushing's disease. In normal horse pituitaries, as in those of other species, most of the bioactive and IR-ACTH was found in PD, much less in PI, and only...
Proopiolipomelanocortin peptides in normal pituitary, pituitary tumor, and plasma of normal and Cushing’s horses. Using RIAs for six regions within proopiolipomelanocortin (proOLMC), gel filtration, and electrophoresis, we studied pituitary peptides in a normal horse and one with Cushing's disease caused by a pars intermedia adenoma. Almost all immunoreactive (IR) ACTH (78%) was 4,500 mol wt (4.5K) ACTH in normal pars distalis, but it was almost 100% corticotropin-like intermediate lobe peptide (CLIP) in normal pars intermedia. alpha MSH and beta MSH were found mainly in pars intermedia: equal concentrations of the beta MSH precursors, beta-lipotropin (beta LPH) and gamma LPH, were found in pars distalis....
In vivo metabolism of [3H]equilin in the pregnant mare. [3H]Equilin [3H-labeled 3-hydroxy-1,3,5(10), 7-estratetraen-17-one] was administered iv to a pregnant mare in the 10th month of gestation. Maternal urine was collected for 3 days, and blood samples were taken 35 min and 3, 6, 12, and 24 h after the injection. The half-life of the disappearance of radioactivity from the blood was approximately 2.5 h. Over 90% of the administered dose was excreted in the first 24 h. The urine was extracted, hydrolyzed, and fractionated. The bulk of the radioactive material (75%) was present in the phenolic sulfate fraction from which radiochemically pure equilin...
A case of pituitary adrenocorticotropin-dependent Cushing’s syndrome in the horse. In the horse, a syndrome of hirsutism, hyperglycemia, glucosuria, polydipsia, polyuria, polyphagia, and progressive debilitation has been recognized. Most often the syndrome has been associated with adenomas of the pars intermedia of the pituitary and bilateral adrenal hyperplasia or nodular hyperplasia involving primarily the zona fasciculata. Previously, the syndrome has been ascribed to compression of the hypothalamus by an expanding but functionally inactive pituitary neoplasm. In the present case, with RIA determination of plasma ACTH concentrations, the syndrome was ascribed to pituitary...
Formation of steroids by the pregnant mare. VI. Metabolism of [14C]farnesyl pyrophosphate and [3H]dehydroepiandrosterone injected into the fetus. A mixture of [4,8,12-14C]farnesyl pyrophosphate and [3H]dehydroepiandrosterone was injected into a horse fetus im during laparotomy, after which maternal urine was collected for 6 days. Steroid conjugates in the urine were extracted with Amberlite XAD-2 resin, hydrolyzed, and separated into phenolic and neutral fractions. Estrone, 17 alpha-estradiol, equilin [3-hydroxy-1,3,5(10),7-estratetraen-17-one], and 17 alpha-dihydroequilin [1,3,4(10),7-estratetraene-3,17 alpha-diol] were isolated from the phenolic fraction and their radiochemical purities were established. Only estrone and 17 alpha-estr...
Effect of luteinizing hormone on the pattern of steroid production by preovulatory follicles of pregnant mare’s serum gonadotropin-injected immature rats. Preovulatory follicles were explanted on the day before ovulation from immature rats given a single injection of Pregnant Mare's Serum gonadotropin (PMS) 2 days earlier. The follicles were incubated for 4 h in modified Krebs bicarbonate buffer containing glucose and albumin in absence or presence of ovine luteinizing hormone (NIH-LH-S18; 0.1-10 mug/ml). The accumulation of progresterone, androstenedione and 17beta-estradiol in the medium was determined by radioimmunoassay. As in indicator of LH exposure the meiotic stage of the follicle-enclosed oocyte was determined at recovery by interferenc...
Effects of ovariectomy and season on plasma luteinizing hormone in mares. Six pony mares were ovariectomized (OVX) on day 16 of diestrus during June and July, 1972, to study short term changes in plasma luteinizing hormone (LH) concentrations. Plasma LH was higher (P less than .05) 3 days after OVX (1.76 ng/ml) than the day after OVX (1.01 ng/ml), and a gradual increase occurred over the first 2 weeks. Elevated plasma LH concentrations similar to mid-estrus levels were present from the 2nd to 11th week post-OVX. In another experiment, the same 6 OVX mares were bled once a month from February, 1973, to January, 1974, to study long-term changes in plasma LH in relatio...
Formation of steroids by the pregnant mare. V. Metabolism of 14C-isopentenylpyrophosphate and 3H-dehydroisoandrosterone injected into the fetus. A mixture of 1-14C-isopentenylpyrophosphate and 3H-dehydroisoandrosterone was injected into a horse fetus intramuscularly during laparotomy, after which maternal urine was collected for 4 days. Steroid conjugates in the urine were extracted with Amberlite XAD-2 resin, hydrolysed and separated into phenolic and neutral fractions. From the phenolic fraction estrone, 17alpha-estradiol, equilin and equilenin were isolated. Only estrone and 17alpha-estradiol contained both 3H and 14C, while the ring B unsaturated estrogens contained only 14C. From the neutral fraction 14C-labeled 3beta-hydroxy-5alp...
Purification and physicochemical properties of the pregnant mare serum gonadotropin (PMSG). A highly purified preparation of PMSG has been obtained from fresh serum and from a commercial preparation. Carbohydrate and amino acid compositions have been determined. The carbohydrate content of PMSG is 46.7% and the molecule is rich in Sialic Acid (13.5%). The apparent molecular weight of PMSG has been determined by SDS polyacrylamide gel electrophoresis. A molecular weight of 53,000 has been found for the unreduced and unalkylated molecule. After reduction and alkylation, the molecular weight fell to 23,000. From these values it has been concluded that PMSG is an oligomeric molecule comp...
Formation of estrogens by the pregnant mare. II. Metabolism of 14C-acetate and 3H-cholesterol injected into the fetal circulation. A mixture of 14C-sodium acetate and 3H-cholesterol was injected into the umbilical circulation of a pregnant mare in the 3OOth day of gestation. The abdomen was closed and urine was collected for 3.5 days. The mare delivered a normal live foal 23 days later. Steroid conjugates present in the maternal urine were hydrolyzed and separated into neutral and phenolic fractions. From the phenolic “sulfate” fraction estrone, 17α-estradiol, equilin, equilenin, and 17α-dihydroequilenin were isolated. Only estrone and 17α-estradiol contained both 3H and 14C, while the ring-B unsaturated estrogens ...
A simple method for the isolation of pregnant mare serum gonadotropin. A simple procedure is described for the purification of pregnant mare serum gonadotropin (PMSG). The purification of PMSG from serum employed pH fractionation with metaphosphoric acid, alcohol precipitation, gel-filtration on Sephadex G-100, and chromatography on sulfoethyl-Sephadex C-50. The specific activity of the final product averaged 15,800 IU/mg and was obtained in yields of 50-80% of the activity initially present in unfractionated serum. The preparation obtained by this procedure has been characterized with respect to biological activity, electrophoresis on columns of polyacrylamide, ...
Preparation and properties of growth hormone from equine pituitary glands. Equine growth hormone has been prepared from acetone-dried residues following extraction of gonadotropins from fresh frozen equine pituitary glands. The growth hormone appeared as a single fraction by gel filtration on Sephadex G-50 and ultracentrifugation. A sedimentation constant of 3.12 was obtained. Preliminary end-group analysis suggested phenylalanine at both aminoand carboxy-terminals. Amino acid analysis of the growth hormone was performed. Four components of equine growth hormone were separated by polyacrylamide column electrophoresis and all 4 were shown to contain growth hormone act...