Decapeptide luteinizing hormone releasing hormone in ovine pineal gland

Ovine pineal gland extracts were examined throughout the year for content and molecular form of immunoreactive (IMR) LH releasing hormone (LH-RH). The content of IMR LH-RH in pineal glands collected in spring and summer was 160-2230 pg/gland, while the content in pineal glands collected in autumn and winter was lower (31-39 pg/gland). Pineal gland IMR LH-RH, purified by affinity and Sephadex G-25 chromatography, yielded displacement curves parallel to those of hypothalamic IMR LH-RH and synthetic LH-RH in radioimmunoassays employing four antisera which require different regions of the decapeptide for effective binding, suggesting considerable similarities in the structure of the molecule. The majority of pineal gland IMR LH-RH behaved identically to hypothalamic IMR LH-RH and synthetic LH-RH on gel filtration, cation exchange chromatography, high-pressure liquid chromatography and cellulose thin-layer chromatography. However, a small amount of a less positively charged LH-RH species was also present in all pineal gland extracts. Our findings indicate that hypothalamic decapeptide LH-RH occurs in the ovine pineal gland.

Depolarization- and ionophore-induced release of octacosa somatostatin from stalk median eminence synaptosomes

Species of somatostatin of higher molecular weight were present in the nerve terminals (synaptosomes) of ovine stalk median eminences and were released by depolarizing stimuli. One of these species was identified as the biologically active molecule octacosa somatostatin. Octacosa somatostatin appears therefore to be secreted into the hypothalamic-hypophyseal system, supporting the concept of a role for this peptide in regulating pituitary hormone secretion.

Isolation and structure of pro-somatostatin: a putative somatostatin precursor from pig hypothalamus

An octacosapeptide that we named pro-somatostatin has been isolated from acid extracts of porcine hypothalami and found to have the amino acid sequence Ser-Ala-Asn-Ser-Asn-Pro-Ala-Met-Ala-Pro-Arg-Glu-Arg-Lys-Ala-Gly-Cys-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Cys. This octacosapeptide possesses high somatotropin (growth hormone) and prolactin release-inhibiting activity in vitro. It also crossreacts strongly with antisera generated against the somatostatin tetradecapeptide. This octacosapeptide is most likely a precursor (pro-hormone) of somatostatin in the hypothalamus. The existence of still larger molecular size precursors of somatostatin was also observed.

The relationship of umbilical cord plasma cortisol levels to amniotic fluid infection

Cord plasma cortisol concentrations were measured in 52 preterm infants and related to amniotic fluid infection as evidenced by positive bacterial cultures. The cortisol levels were significantly raised in the group with an infected intra-uterine environment (519 +/- 158 nm/l) compared with the non-infected group (325 +/- 134 nm/l). This effect was independent of length of gestation, duration of rupture of membranes, or duration of labour. Infants with fetal growth retardation had raised cortisol levels (555 +/- 207 nm/l), while maternal dexamethasone therapy suppressed the levels (197 +/- 76 nm/l). Only 2 infants developed hyaline membrane disease, and in both bacterial culture was negative and cord cortisol levels low (231 and 239 nm/l). It is suggested that amniotic fluid infection may play a role in reducing the incidence of hyaline membrane disease by increasing fetal cortisol production.

A radio-immunoassay of 17-alpha-hydroxyprogesterone

A method is described for the determination of 17 alpha-hydroxyprogesterone (17-OHP) in plasma. Antisera were raised in rabbits against 11-deoxycortisol-21-hemisuccinate-bovine serum albumin (11-DOC-21-HS-BSA) and 17 alpha-hydroxyprogesterone-3-carboxymethyloxime-bovine serum albumin (17-OHP-3-CMO-BSA). An antiserum to 11-DOC-21-HS-BSA exhibited cross-reaction with progesterone (29%), 11-deoxycortisol (100%), cortisol (17%) and testosterone (10%) and was therefore not appropriate for quantitation of 17-OHP in plasma. An antiserum to 17-OHP-3-CMO-BSA cross-reacted with progesterone (9,7%), 11-deoxycortisol (50%) and less than 1% with all other major naturally occurring steroid hormones. A radio-immunoassay (RIA) was developed using the antiserum to 17-OHP-4-CMO-BSA. The intra-assay and interassay coefficients of variation were 7,2% and 10,5% respectively. The normal ranges (nmol/l plasma) of samples extracted with hexane:benzene (1:1) and purified by Sephadex LH-20 chromatography were 0,28-4,7 for men, 0,84-3,0 for women (follicular phase), 3,0-11,0 for women (luteal phase), 4,6-22,1 for pregnant women, 18,5-123,9 for cord blood, 0,12-5,0 for children and 56,3-1 032 for persons with congenital adrenal hyperplasia (CAH) due to a 21-hydroxylation enzyme defect. Sephadex LH-20 purification of plasma extracts could be omitted when using the RIA as a screening procedure for CAH due to a 21-hydroxylation enzyme defect.

Comparative aspects of luteinizing hormone-releasing hormone structure and function in vertebrate phylogeny

Immunoreactive LHRH was detected in hypothalamic and extrahypothalamic brain extracts of the rat, bird (pigeon and chicken), reptile (tortoise and lizard), amphibian (frog and toad), teleost (cichid), and elasmobranch (dogfish) and in the whole brain of the cyclostome (bagfish). The concentration of hypothalamic immunoreactive LHRH was more than 5-fold greater than that of the extrahypothalamic brain. Mammalian and amphibian hypothalamic immunoreactive LHRH yielded displacement curves parallel to those of synthetic LHRH in assays employing four antisera which recognize different regions of the decapeptide, thus suggesting a similarity in the structure of their LHRH. Hypothalamic immunoreactive LHRH from the bird, reptile, teleost, and elasmobranch differed from the mammalian and amphibian peptide in yielding displacement curves nonparallel to those of synthetic LHRH with three different antisera (1076, 743, and 744) which bind between Trp3 and Pro9 of LHRH. The differenece in structure appears to be near Leu7. With antiserum 422 which binds the NH2- and CO2H- termini of LHRH, bird, reptile, and teleost hypothalamic extracts yielded displacement curves parallel to that of synthetic LHRH. Bird, reptile, and teleost hypothalamic extracts showed displacement curves parallel to each other in all assays. In studies on the relative quantitation of LHRH, all four antisera gave similar values of immunoreactive LHRH concentration in mammalian hypothalamic extracts and in amphibian hypothalamic extracts. By contrast, assay of bird, reptile, teleost, and elasmobranch hypothalamic extracts with antiserum 422 gave much higher values than did the other antisera, suggesting that the LHRH peptide is structurally different from mammalian and amphibian LHRH in the region of Leu7 but similar at the NH2- and CO2H-termini. These conclusions are supported by studies on the biological activity of hypothalamic LHRH from the different species using dispersed ovine anterior pituitary cells in culture. The LH release responses to equivalent amounts of immunoreactive LHRH (as measured by antiserum 422 which binds a region of LHRH essential for biological activity) from the various species were similar, indicating that the biologically active region of the molecule has been conserved in evolution. Structural differences in vertebrate hypothalamic immunoreactive LHRH were confirmed by cation exchange and high pressure liquid chromatography. Our findings of differences and similarities in vertebrate LHRH support a contemporary phylogenetic scheme.

Seasonal changes of sexual and territorial behaviour and plasma testosterone levels in male lesser sheathbills (Chionis minor)

Lesser Sheathbills Chionis minor (Aves: Charadriiformes) have a brief annual breeding season but under certain circumstances territoriality persists outside the breeding season. Seasonal increases in plasma testosterone levels in free-living adult males coincided with increases in the mass of tests, the seasonal peak in mutual pair displays and the occurrence of nest-building and copulation. Territorial aggression outsids the breeding season was not dependent on high testosterone levels.

Radioimmunoassay of methionine(5)-enkephalin sulphoxide: phylogenetic and anatomical distribution

A sensitive and specific radioimmunoassay (RIA) for the oxidised form of methionine(5)-enkephalin (Met(5)-Enk), Met(5)-Enk sulphoxide (Met(5)-Enk-S), has been developed. Antisera were raised in rabbits against Met(5)-Enk coupled to carrier proteins with glutaraldehyde or carbodiimide. Displacement of (125I) Met(5)-Enk bound to antiserum by Met(5)-Enk was poor, but Met(5)-Enk-S displayed good displacement suggesting that the Met(5)-Enk immunogen was oxidised to Met(5)-Enk-S and that the antisera were formed against this compound. The sensitivity of the RIA for Met(5)-Enk-S was 0.02 pmole/tube using the most sensitive antiserum. The antisera showed negligible cross-reactivity with leucine(5)-enkephalin and with both native and oxidised endorphins. Cross-reactivity was between 15% and 28% with the fragment Met(5)-Enk (2--5) sulphoxide and between 9% and 25% with D-Ala(2)-Met(5)-Enk sulphoxide. The antisera showed less than 0.01% cross-reactivity with other Met(5)-Enk fragments and naturally occurring neuropeptides. Tissue extracts were oxidised with hydrogen peroxide prior to assay. Met(5)-Enk-S immunoreactivity (IMR) was detected in brain, pituitary gland, pancreas, and intestine extracts of the rat, chicken, toad and teleost, and in cerebral-suboesophageal ganglion extracts of the snail. All tissue extracts showed parallelism in serial dilution to synthetic mammalian Met(5)-Enk-S, suggesting possible immunological identity. The results indicate that spontaneous oxidation of Met(5)-Enk immunogen occurs such that antisera are produced against the sulphoxide analogue of Met(5)-Enk, and may account for the relative insensitivity of some published RIAs using Met(5)-Enk standard. Our findings demonstrate a wide phylogenetic and anatomical distribution of Met(5)-Enk IMR.

Annual reproductive pattern in the springhaas, Pedetes capensis

The springhaas, Pedetes capensis, is capable of breeding throughout the year in the Orange Free State province of South Africa and fetuses of all sizes were found throughout the year. The highest incidence of pregnancies was found during the winter months July and August with the majority of embryos and small fetuses occurring between April and July and most larger fetuses thereafter. Birth weight was probably 280-300 g. Juveniles stay in the burrows until they have attained a body mass of 1.5 kg. Once spermatogenesis is established at a liveweight of about 2.5 kg it appears to be continuous. There was an indication that plasma LH and progesterone concentrations were related to corpus luteum diameter.

Phylogenetic and anatomical distribution of somatostatin in vertebrates

Immunoreactive GH release-inhibiting factor [somatostatin (SRIF)] was detected in hypothalamus, extrahypothalamic brain, pancreas, and stomach extracts of the rat, pigeon, tortoise, frog, teleost (cichlid), and elasmobranch (dogfish) and in the whole brain of the cyclostome (hagfish). The SRIF concentration was higher in the pancreas and gastrointestinal tract than in the hypothalamus and extrahypothalamic brain in most species. Extracts of the various tissues from the different species assayed in serial dilutions gave displacement curves parallel to those of synthetic mammalian SRIF. Cation exchange chromatography of hypothalamic extracts from the various species revealed two major immunoreactive peaks, one of which correpsonds to synthetic SRIF in elution volume, the other being less basic. Affinity chromatography-purified immunoreactive SRIF from frog brain, pancreas, and stomach extracts coeluted with synthetic SRIF in high pressure liquid chromatography. The results indicate that immunoreactive SRIF in various tissues and in different vertebrates is indistinguishable and suggest that there has been no change in the molecule during at least 400 million yr of evolution.

Gas-liquid chromatographic analysis of urinary steroids

A method for gas-liquid chromatographic separation and quantitation of urinary steroid metabolites is described. A normal reference range has been established and classic examples of urinary steroid profiles of the major steroid disorders are given.

Heterogeneity of vertebrate luteinizing hormone-releasing hormone

Radioimmunoassay and chromatography analyses of hypothalamic luteinizing hormone-releasing hormone (LHRH) have demonstrated the presence of LHRH-like immunoreactive peptides in a wide range of vertebrates. Contrary to previous reports, the molecule differs in various vertebrates. Avian, reptilian, and teleostean LHRH's are chemically distinct from the mammalian peptide but are in themselves indistinguishable. However, amphibian LHRH appears to be identical to the mammalian peptide. These findings have interesting evolutionary implications.

Somatostatin immunoreactive peptides of higher molecular weight in ovine hypothalamic extracts

U.C.T./M.R.C. Protein Research Unit, Department of Chemical Pathology, Medical School, Observatory 7925, Cape Town, Republic of South Africa

(Received 26 January 1978)

Higher molecular weight (HMW) immunoreactive forms of somatostatin have been reported in extracts of ovine hypothalami (Vale, Ling, Rivier, Villarreal, Rivier, Douglas & Brown, 1976), rat pancreas and stomach (Arimura, Sato, Dupont, Nishi & Schally, 1975) and human pancreatic somatostatinoma (Larsson, Hirsch, Holst, Ingemansson, Kühl, Jensen, Lundquist & Rehfeld, 1977). However, the possibility that the HMW immunoreactive substances were oligomers of somatostatin or somatostatin bound to larger molecules was not excluded. The present study was undertaken to establish that authentic HMW immunoreactive somatostatin is present in the ovine hypothalamus and to glean information on the structural relationship of the HMW species with somatostatin.

Sheep hypothalami were extracted and subjected to gel permeation chromatography as described previously by Millar, Aehnelt & Rossier (1977). Fractions were assayed for somatostatin immunoreactivity

Hormonal effects of wedge resection of polycystic ovaries

Plasma FSH, LH, estradiol, testosterone, and progesterone were measured serially before, during, and after bilateral ovarian wedge resection in 2 patients with polycystic ovaries. Preoperatively both were anovulatory with persistently elevated plasma LH values and 1 patient had high testosterone concentrations. Plasma FSH, estradiol, and progesterone were within the normal midfollicular phase range. The LH:FSH ratio was increased and no cyclic gonadotropic activity occurred. During surgery progesterone levels rose while estradiol concentrations fell. In both patients, the initial reduction in estradiol secretion was observed after unilateral wedge resection but testosterone concentrations only declined 6-24 hours postoperatively. During the first postoperative week the LH:FSH ratio fell significantly and cyclic gonadotropic activity, in the form of sporadic LH and FSH spurts, was noted. In the second week after surgery, and estradiol surge occurred followed by preovulatory LH and FSH peaks, ovulation, and a normal luteal phase. Spontaneous menstruation occurred by the end of the first postoperative month and both patients conceived within 4 months of surgery.

Breast cancer and hormone receptors: a preliminary report

An assay is available to determine the presence or absence of oestrogen receptors in breast cancer cells. The presence of oestrogen receptors predicts a 60% response rate to empirical hormonal therapy, and the absence a 10% response rate. Early evidence suggests that the additional presence of other hormone receptors in breast cancer cells will improve this response rate.

Application of ovine luteinizing hormone (LH) radioimmunoassay in the quantitation of LH in different mammalian species

A sensitive double antibody radioimmunoassay has been developed for measuring luteinizing hormone (LH) in various African mammalian species, using rabbit anti-ovine LH serum (GDN 15) and radioiodinated rat LH or ovine LH. Serum and pituitary homogenates from some African mammals (hyrax, reedbuck, sable, impala, tsessebe, thar, spring-hare, ground squirrel and cheetah, as well as the domestic sheep, cow and horse and laboratory rat and hamster) produced displacement curves parallel to that of the ovine LH standards. The specificity of the assay was examined in detail for one species, the rock hyrax. Radioimmunoassay and bioassay estimates of LH in hyrax pituitaries containing widely differing quantities of pituitary hormones were similar. In sexually active male hyrax mean plasma LH was 12.1 ng/ml and pituitary LH 194 microgram/gland, but in sexually quiescent hyrax mean plasma LH was 2.4 ng/ml and mean pituitary LH 76 microgram/gland. Intravenous injection of 10 microgram of luteinizing hormone releasing hormone increased mean LH levels in hyrax from 0.9 ng/ml to 23.2 ng/ml by 30 min. Conversely, im injection of 250 microgram testosterone induced a fall in LH levels in male hyrax from 1.7 ng/ml to 0.7 ng/ml 6 h after administration. Although the specificity of the assay for quantitating plasma LH in other species was not categorically established, there was a good correlation between plasma LH concentration and reproductive state in the bontebok, impala, spring-hare, thar, cheetah, domestic horse and laboratory rat, suggesting the potential use of the antiserum in quantitating LH in a variety of mammalian species.

A simple radioimmunoassay for plasma cortisol: comparison with the fluorimetric method of determination

A quick and simple method for the radioimmunoassay of plasma cortisol is described. The mean morning plasma cortisol concentration in 43 normal subjects was 9.8 +/- 3.1 (S.D.) microgram/100 ml with a range of 5.0-19.5 microgram/100 ml. Mean midnight concentration in 24 normal subjects was 4.3 +/- 2.3 (S.D.) microgram/100 ml with a range of 1.4-9.6 microgram/100 ml. When compared with the fluorimetric method the mean results by radioimmunoassay of 154 routine specimens were 23% lower. In samples from unstimulated patients, regression analysis of results obtained by the two methods gave a correlation coefficient (r) of 0.93, regression line slope of 1.1, and intercept of 1.4 microgram. Mean radioimmunoassay results were 15% lower. When plasma cortisol concentration was above the normal range (greater than 30 microgram/100 ml) the regression line slope was 0.87, the intercept 17.9 microgram, r = 0.87 and mean radio immunoassay results were 37% lower. Plasma cortisol concentration in patients after insulin or Synacthen stimulation exhibited similar responses when measured by either method. Plasma cortisol concentration in normal subjects given metyrapone was lower when measured by radioimmunoassay (mean +/- S.D. = 8.7 +/- 2.7 microgram/100 ml) than when measured by fluorimetry (18.5 +/- 10.8 microgram/100 ml). The diagnostic usefulness of the two methods, ease of assay, and costs are compared.