bluuebunny/crossref_metadata_2025 huggingface dataset:
THE EFFECT OF SALT LOADING ON THE PITUITARY PROLACTIN LEVELS OF THE DOMESTIC DUCK (ANAS PLATYRHYNCHOS) AND JUVENILE HERRING OR LESSER BLACK-BACKED GULLS (LARUS ARGENTATUS OR LARUS FUSCUS)
Authors: ENSOR D. M. , PHILLIPS J. G.
Published: December 2008

The pituitary prolactin levels were measured in the domestic duck (Anas platyrhynchos) and in juvenile gulls from a mixed population of herring and lesser black-backed gulls. In the domestic duck the pituitary prolactin levels increased on the 2nd and 3rd days of maintenance on 0·3 m-NaCl, but by the 5th day they had fallen appreciably below the control levels. Maintenance of gulls with 0·3 m-NaCl produced no change in pituitary prolactin levels after 5 days, but a marked fall in prolaction levels when the birds were maintained on 0·7 m-NaCl for 5 days. This difference in response between the two species may be related to their degree of adaptation to a marine environment.
THE RESPONSE OF PLASMA SUGAR, FREE FATTY ACIDS, 11-HYDROXYCORTICOSTEROIDS AND GROWTH HORMONE TO INSULIN-INDUCED HYPOGLYCAEMIA AND VASOPRESSIN IN PRIMARY MYXOEDEMA
Authors: VINCE F. P. , BOUCHER BARBARA J. , COHEN R. D. , GODFREY JEAN
Published: December 2008

The plasma sugar, free fatty acids (FFA), 11-hydroxycorticosteroids (11-OHCS) and growth hormone (GH) response to insulin-induced hypoglycaemia, have been studied in 19 patients with primary myxoedema and 13 normal subjects. Nine of the myxoedematous patients were restudied after treatment. The plasma 11-OHCS response to lysine vasopressin (LVP) was studied in the myxoedematous subjects and again in eight of them after treatment.

In myxoedema the plasma sugar falls to a lesser extent and more slowly in response to insulin than normal and takes longer to recover. The fall in plasma FFA is not different from normal, but recovery of plasma FFA is delayed. The responses to insulin-induced hypoglycaemia of plasma GH and 11-OHCS may be smaller than normal in myxoedema and tend to improve on treatment. Altered GH and 11-OHCS responses to insulin-induced hypoglycaemia in myxoedema are not necessarily due to pituitary or hypothalamic dysfunction. No difference was found in the response of plasma 11-OHCS to LVP before and after treatment. Pituitary function cannot be fully assessed in the presence of hypothyroidism.
CHANGES IN ENZYMIC ACTIVITY, CHEMICAL COMPOSITION AND HISTOLOGY OF THE MAMMARY GLANDS AND METABOLITES IN THE BLOOD OF LACTATING RABBITS AFTER HYPOPHYSECTOMY AND REPLACEMENT THERAPY WITH SHEEP PROLACTIN, HUMAN GROWTH HORMONE OR BOVINE GROWTH HORMONE
Authors: HARTMANN P. E. , COWIE A. T. , HOSKING ZENA D.
Published: December 2008

Five groups of five lactating rabbits each were used. Milk yield was recorded from the 8th day of lactation onwards and on the 10th day of lactation the rabbits received the following treatments: Group S, sham-operation with saline (1 ml/12 h); Group P, hypophysectomy with sheep prolactin (1 mg/12 h); Group H, hypophysectomy with human growth hormone (1 mg/12 h); Group B, hypophysectomy with bovine growth hormone (1 mg/12 h) and Group C, hypophysectomy with saline (1 ml/12 h). The injections of saline or hormones were continued for 5 days and at the end of this period a blood sample was taken, the animals were killed and their mammary glands removed for histological examination and assay of the following enzymes: 6-phosphogluconate dehydrogenase (EC 1.1.1.44), phosphofructokinase (EC 2.7.1.11), phosphoglucomutase (EC 2.7.5.1), UDP-glucose pyrophosphorylase (EC 2.7.7.9), acetyl-CoA carboxylase (EC 6.4.1.2), acetyl-CoA synthetase (EC 6.2.1.1) and ATP-citrate lyase (EC 4.1.3.8). On the 5th day after surgery the concentrations of blood l-lactate and pyruvate and plasma free fatty acids and protein were similar in all groups, whereas plasma glucose was higher in groups S, B and H than in groups P and C. Although the weights of pituitary target organs (adrenals, thyroid and ovaries) were similar in all groups, the weights (g/kg body weight) of mammary tissue varied markedly, group S being the heaviest and group C the lightest. Milk yields, 5 days after surgery, for groups P and H were about 50% that for S, whereas those for B and C were 15 and 4% respectively. Where possible the enzyme activity was expressed as a ratio of the rate of synthesis of the end product of the pathway in which the enzyme occurred. With the exception of acetyl-CoA carboxylase which may have had a rate-limiting role in the synthesis of milk fat, enzymic activity in vitro was in excess of that required in vivo for the synthesis of either milk fat or lactose. It appeared that the rate of milk synthesis depended upon the degree of maintenance of the secretory epithelial cells within the mammary gland rather than a block in the synthetic pathways within these cells.
RELATIONSHIP BETWEEN INSULIN CONCENTRATIONS IN PLASMA AND PANCREAS OF FOETAL AND WEANLING RATS
Authors: BLÁZQUEZ E. , MONTOYA E. , QUIJADA CLEMENTE LÓPEZ
Published: December 2008

During the third part of pregnancy in the rat the concentrations of plasma insulin and tissue glycogen in the foetus increase progressively. These levels and the release of insulin by pancreas incubated in vitro were significantly higher than the values found in adult non-pregnant rats. After birth the correlation between plasma insulin concentration and the stores of glycogen was also evident. In the first day of life, the concentrations of plasma insulin, glycogen in liver, striated muscle and kidney decreased significantly; these values decrease even more during the first 15 days of lactation. After weaning started (20 days post partum), rapid increases of insulin and glycogen were observed, parallel to the slow growth of the newborn rat during the first 15 days of life and the more rapid rate of growth after 20 days. Similarly, the insulin content of the pancreas increased more significantly during the period in which pancreatic weight and plasma insulin concentrations increased more slowly. These results show that when plasma insulin concentrations increase, body growth and stores of glycogen are higher, suggesting an anabolic role of insulin in the foetal and newborn rat.
PROLACTIN—THYROID INTERACTION IN THE NEWT, DIEMICTYLUS VIRIDESCENS
Authors: GONA A. G. , PEARLMAN T. , ETKIN W.
Published: December 2008

Prolactin—thyroid interaction was analysed in the second metamorphosis of Diemictylus viridescens. Intraperitoneal injections of either 3 μg thyroxine (T4) or 0·2 mg propylthiouracil (PTU) on alternate days failed to induce second metamorphosis in the red eft (land stage); 0·1 mg PTU inhibited prolactin-induced second metamorphosis. The effect of prolactin was facilitated by 0·1 μg T4. However, 0·5 μg T4 inhibited water-drive behaviour after initial stimulation of integumentary changes and water-drive. Larger doses of T4 (1–3 μg) proved fatal to the efts when given together with 0·5–40 μg prolactin.

The results indicate that a certain optimal level of thyroid hormone is needed for the initiation of second metamorphosis. Nevertheless, prolactin—thyroid antagonism, previously reported in tadpoles, also occurs in the newt. Second metamorphosis appears to be brought about by a reversal of the low prolactin—high thyroid level of the eft phase to a high prolactin—low thyroid level.
UTERINE AUTOTRANSPLANTATION TO THE ABDOMINAL WALL IN THE GUINEA-PIG
Authors: BLAND K. P.
Published: December 2008

A method for autotransplantation of the uterus of the guinea-pig to the abdominal wall is described. Complete uterine autotransplantation by this method caused extended oestrous cycles (mean 24·67 days). Similar transplantation but without disconnexion of the cervical end of the uterus gave rise to cycles of similar length (mean 24·75 days) but transplantation without disconnexion of the tubal ends allowed the occurrence of normal cycles (mean 16·20 days). The site of metabolism of the uterine luteolytic factor is discussed.
DAILY RHYTHM OF PLASMA TYROSINE IN FASTING SUBJECTS
Authors: CAVAGNINI F. , LITTA-MODIGNANI R.
Published: December 2008

The daily rhythm of plasma tyrosine was studied in obese subjects during total fasting, because of the relative constancy of the metabolic processes in this state. The plasma levels of tyrosine showed circadian fluctuations which were similar, although less pronounced, to those observed by other authors. The lowest values occurred at 03.00 h and the highest at 08.00 h with a second rise at 19.00 h.
ISOLATION OF RADIOACTIVE OXYTOCIN AND VASOPRESSIN FROM THE POSTERIOR PITUITARY GLAND OF THE RAT AFTER THE INJECTION OF LABELLED TYROSINE INTO THE CEREBROSPINAL FLUID
Authors: PICKERING B. T. , JONES C. W.
Published: December 2008

A method is described for the preparation of isotopically pure [3H]oxytocin and [3H]vasopressin from the pooled posterior pituitary glands of groups of four or five rats after the intracisternal injection of [3H]tyrosine. Hormones were separated from deproteinized neurohypophysial extracts by chromatography on Amberlite CG-50, and further purified by chromatography on carboxymethylcellulose. In this way, samples of the hormones were obtained with a very high degree of isotopic purity. The method is suitable for studying the effects of stimuli to the hypothalamo—neurohypophysial system on the biosynthesis and transport of the hormones.
ELIMINATION OF THE FERGUSON REFLEX BY SECTION OF THE PELVIC NERVES IN THE LACTATING GOAT
Authors: PEETERS G. , de VOS N. , HOUVENAGHEL A.
Published: December 2008

Distension of the vagina by an inflated balloon induces milk ejection in goats. This reflex (the Ferguson reflex) is based on a neurohormonal mechanism. In three goats the reflex was abolished after bilateral section of the complex pelvic nerves plus caudal rectal nerves. Bilateral section of the pelvic nerves only, caused a complete elimination of the reflex in 11 out of 13 goats; in the two remaining animals, the reflex was abolished after a supplementary section of the pudendal nerve plus caudal rectal nerves. The reflex remained intact in one goat in which first the caudal rectal nerves and subsequently the pudendal nerve were cut. Elimination of the Ferguson reflex was accompanied by a marked reduction of the intensity of straining movements which are normally induced by distension of the vagina. Bilateral section of the pelvic nerves provoked a severe but temporary paralysis of the large intestine with blocking of the defaecation reflex. It is suggested that in ruminants the afferent pelvic nerves are involved in the release of oxytocin and in the intense straining occurring during the phase of expulsion at parturition.
4-THREONINE ANALOGUES OF NEUROHYPOPHYSIAL HORMONES WITH SELECTIVELY ENHANCED OXYTOCIN-LIKE ACTIVITIES
Authors: SAWYER W. H. , MANNING M.
Published: December 2008

The 4-threonine analogues of oxytocin and of mesotocin and isotocin were prepared by solid-phase synthesis. [4-Threonine]-oxytocin is about twice as active as oxytocin in rat uterus assays in vitro and in vivo and about three times as active in fowl vasodepressor assays. It is slightly more active than oxytocin in rat or rabbit milk-ejection assays. When infused intravenously into water-loaded rats it causes much less depression of diuresis than does an equal dose of oxytocin. [4-Threonine]-oxytocin has much less vasopressor activity than oxytocin. [4-Threonine]-mesotocin also shows enhanced oxytocin-like properties. Its oxytocic activity is equal to or greater than that of oxytocin and its fowl vasodepressor potency is about the same as that of [4-threonine]-oxytocin, 1500 u./mg. It also has less antidiuretic and vasopressor activities than mesotocin. Thus 4-threonine analogues, containing nothing but common l-amino acids, appear to have more of the specific oxytocin-like properties and less of the vasopressin-like properties than do oxytocin or mesotocin. Thus they may be considered improvements on the natural hormones. In this respect they are unique among the reported synthetic analogues of natural peptide hormones.

Substitution of 4-threonine in the weakly-active analogue [3-leucine]-oxytocin also increases its oxytocic and fowl vasodepressor activities. Thus a threonine in the 4-position appears to endow oxytocin-like peptides with greater specific activities than do the amino acids that occur naturally in this position, glutamine and serine. These observations may be of interest when considered (a) from an evolutionary viewpoint, (b) in attempting to interpret relations between molecular structures and biological activities, and (c) as describing peptides with more of the desired properties of oxytocin and less of the undesired properties which might have therapeutic advantages over the natural hormone.
THE ACTION OF ADRENOCORTICOTROPHIN ON THE FREE NUCLEOTIDE POOL AND RNA SYNTHESIS IN RAT ADRENALS AND LIVER
Authors: BOYADJIEV S. I. , HADJIOLOV A. A.
Published: December 2008

The action of adrenocorticotrophin (ACTH) in vivo on the amount and [32P]phosphate labelling of free adenine nucleotides and RNA of rat liver and adrenals was studied. Treatment with ACTH did not alter the total amount of free adenine nucleotides. In both the liver and adrenals the amount of ATP decreased, while that of ADP and AMP increased. As a result a more than twofold decrease of the ATP: ADP + AMP ratio was caused by ACTH. This effect was observed 2 h after ACTH administration and remained unchanged up to the 24th hour.

Three hours after [32P]phosphate administration, the labelling of the α-phosphate of free adenine nucleotides in liver was more than five times higher than that in the adrenals. After 24 h of treatment with ACTH the incorporation of [32P]phosphate into free adenine nucleotides of the adrenal was decreased, while that of liver was increased.

The labelling of the high-molecular weight RNA of the adrenals and liver was of the same order. A similar correlation was found when the labelling of AMP obtained from RNA by snake venom phosphodiesterase hydrolysis was compared. Treatment with ACTH decreased the labelling of RNA in the adrenals, while the labelling of RNA in liver was increased. The changes in the labelling of RNA in both organs reflect the variations in the labelling of free adenine nucleotides.

The results are discussed and it is suggested that ACTH treatment in vivo affects the amount and the turnover of free nucleotides in the adrenals and liver. The variations in RNA labelling are secondary and reflect the turnover of the free nucleotides.
A DECREASED RESPONSE TO PARATHYROID HORMONE IN MAGNESIUM DEFICIENCY
Authors: MacMANUS J. , HEATON F. W. , LUCAS P. W.
Published: December 2008

The effect of magnesium deficiency on the response to parathyroid hormone has been investigated in vitro and in vivo. Parathyroid hormone increased the release of calcium, inorganic phosphate and hydroxyproline from rat femora into the incubation medium, but had a lesser effect on bones from magnesium-deficient animals than on femora from control rats. Similarly, injection of the hormone into thyro-parathyroidectomized rats produced smaller rises in plasma calcium and magnesium concentrations in magnesium-deficient rats than in control animals. It is concluded that magnesium deficiency inhibits the action of parathyroid hormone on its target organs.
HISTOCHEMICAL STUDIES OF BOVINE SEMINAL VESICLES DURING POSTNATAL DEVELOPMENT
Authors: RAMA F. , CASTELLANO M. A. , GERMINO N. I. , MICUCCI M.
Published: December 2008

The location of aldose and ketose reductases and of isocitric, succinic, malic and α-ketoglutaric dehydrogenases was studied by histochemical methods in the seminal vesicles of the bull, bull calf and castrated bulls.

The appearance of aldose and ketose reductase activity coincides with that of significant quantities of fructose collected from the accessory glands of calves of 5·5 months of age.

The enzymes of the Krebs' cycle, isocitric, succinic, malic and α-ketoglutaric dehydrogenases, could not be histochemically demonstrated in the seminal vesicles of bulls, bull calves and castrated young bulls.

The factors determining the high citric acid concentrations in bull seminal vesicles are discussed.
GONADOTROPHIC HORMONE SECRETION IN THE FEMALE RING DOVE IN RESPONSE TO VISUAL AND AUDITORY STIMULATION BY THE MALE
Authors: BARFIELD R. J.
Published: December 2008

Female ring doves secrete gonadotrophic hormone in response to courtship behaviour of the male. This investigation was concerned with the quantitative relationship between the courtship stimulation presented to females and the responses of their reproductive systems. In a first experiment the degree of female reproductive tract development was found to be correlated with the length of time of daily exposure to a courting male. In a second experiment exposure time was held constant and the amount of courtship presented to females was varied by using different programmes of stimulation by males. Here too, the degree of female reproductive tract development was correlated with the amount of daily courtship behaviour presented. It therefore appears that in the female ring dove secretion of gonadotrophin is graded in accordance with the amount of courtship behaviour perceived by her.
EFFECTS OF PROLACTIN ON SPERMATOGENESIS IN HYPOPHYSECTOMIZED MICE
Authors: BARTKE A.
Published: December 2008

Hypophysectomized mice were treated daily for 28 days with 12 i.u. prolactin, 10 μg luteinizing hormone (LH), 10 μg LH plus 12 i.u. prolactin, 50 μg testosterone propionate (TP), or 50 μg TP plus 12 i.u. prolactin. The yield of spermatogenesis was studied quantitatively from the counts of spermatogonia, preleptotene and pachytene spermatocytes and spermatids in the seminiferous tubules at stage VII of spermatogenesis. Prolactin administered alone caused a small, but significant, increase in the yield of spermatogenesis. Treatment with a mixture of LH, follicle-stimulating hormone and growth hormone in amounts 1·5 times higher than those reported as contaminants of prolactin had similar effects. Injections of LH or TP caused partial restoration of spermatogenesis. The yield of spermatogenesis was significantly higher in animals given LH plus prolactin than in the animals given LH alone. Prolactin, however, did not augment the effects of TP on spermatogenesis. It is concluded that prolactin acts on the Leydig cells of the testis to increase their responsiveness to LH. More androgen appears to be produced under the influence of LH when prolactin is also present.
THE EFFECT OF HYPOPHYSECTOMY ON THE RESPONSE OF THE SEBACEOUS GLAND TO TESTOSTERONE PROPIONATE
Authors: THODY A. J. , SHUSTER S.
Published: December 2008

The effect of varying doses of testosterone propionate (TP) on the sebum secretion and preputial gland weight of castrated and hypophysectomized—castrated rats was studied. The changes in preputial gland weight closely paralleled those of sebum secretion. Small doses of TP (0·05 mg) stimulated sebum secretion in hypophysectomized-castrated rats, but not in the castrated rats. Higher doses of TP increased sebum secretion in both the hypophysectomized—castrates and the castrated rats.

While 0·5 mg TP completely restored sebum secretion to normal levels in castrated rats but not in the hypophysectomized—castrated rats, the actual increase in sebum secretion produced by this dose of TP was similar in both groups. It is concluded that at physiological doses the action of TP on the sebaceous glands is independent of the pituitary. However, the presence of the pituitary is required for normal sebaceous gland activity.
REGULATION OF PITUITARY OVULATING HORMONE CONCENTRATION IN THE IMMATURE RAT TREATED WITH PREGNANT MARE SERUM
Authors: ZARROW M. X. , DINIUS JANET
Published: December 2008

The concentration of luteinizing hormone (LH) in the pituitary gland of the 28-day-old female rat increased from a value of 8·0 μequiv./mg fresh anterior pituitary at zero time to 20·1 μg at 51 h after treatment with 30 i.u. pregnant mare serum (PMS). The level then fell to 8·1 μg at 56 h. PMS had no effect on pituitary LH levels in the ovariectomized rat. Three daily injections of 5·0 μg of oestradiol benzoate caused an increase in pituitary LH levels to 16·1 μg at 51 h after the onset of the oestrogen treatment. This value is not significantly different from the level (20·1 μg/mg fresh weight) found in the intact, PMS-treated, immature rat. Uterine weights were also comparable for the two groups. Treatment with lower doses of oestradiol benzoate had no effect on pituitary LH levels and also failed to increase the uterine weight to values comparable with those obtained after PMS treatment. Treatment of 28-day-old, intact, female rats with 2 mg of progesterone at 24 h after the PMS injection resulted in a significant drop in pituitary LH levels.
THE EFFECT OF OVARIAN STEROIDS ON HYPOTHALAMIC THRESHOLDS FOR OVULATION IN THE FEMALE RAT
Authors: McDONALD P. G. , GILMORE D. P.
Published: December 2008

Electrochemical stimulation of the basal and preoptic hypothalamus, under sodium pentobarbitone anaesthesia, was carried out on the day of pro-oestrus in normal cycling and in ovarian hormone-treated female rats. Control rats ovulated in response to 25, 50 and 100 μA for 60 s in the median eminence and to 10 μA for 60 s in the preoptic area. Oestradiol (1 μg) given 24 h before median eminence stimulation significantly increased the number of rats ovulating. An injection of progesterone (1 mg) 24 h before median eminence stimulation did not affect the number of animals ovulating or the number of ova shed. In contrast, there was a significant reduction in the number of animals ovulating after preoptic stimulation. Stimulation of the median eminence 2–4 h after progesterone administration increased the number of animals ovulating. The results suggest that both oestradiol and progesterone exert a positive feedback effect at or below the level of the median eminence and that the negative feedback effect of progesterone is exerted on the preoptic area.
EFFECTS OF INTRADUCTAL PROLACTIN ON SOME ASPECTS OF THE ULTRA-STRUCTURE AND BIOCHEMISTRY OF MAMMARY TISSUE IN THE PSEUDOPREGNANT RABBIT
Authors: FIDDLER T. J. , BIRKINSHAW MARGARET , FALCONER I. R.
Published: December 2008

A study of the ultrastructure of the secretory epithelial cells of the mammary gland was carried out in virgin oestrous rabbits, pseudopregnant rabbits and pseudopregnant rabbits injected with prolactin to induce lactogenesis. Ultrastructural modifications of the mammary epithelial cells, from inactivity to active secretion after an intraductal injection of prolactin, are described. The changes produced after prolactin injection were characterized by a progressive increase in endoplasmic reticulum and in ribosomes in the cytoplasm. This was evident after 12–24 h. By the 2nd or 3rd day after hormone administration the cells had differentiated into active secretory epithelium. These cells were characterized by large numbers of ribosomes in the cytoplasm; an extensive development of rough endoplasmic reticulum; development of cisternae from the enlarging rough endoplasmic reticulum; hypertrophy of the Golgi apparatus and smooth endoplasmic reticulum; and the presence of protein granules in the vacuoles which were particularly abundant in the cytoplasm near the duct lumen. The presence of lipid droplets in the cells was less indicative of an active secretory state since they were also observed in mammary tissue from pseudopregnant rabbits. Biochemical investigation of the response of pseudopregnant mammary tissue to intraductal prolactin showed no significant rapid effects on either casein-like protein or lactose biosynthesis, but increases in both substances were observed on the 3rd day after hormone administration.
REDUCED THYROID ACTIVITY IN JAMAICANS
Authors: HARLAND W. A. , RICHARDS R. , GOLDBERG I. J. L.
Published: December 2008

The results presented demonstrate reduced thyroid activity in euthyroid Jamaicans. In 15 subjects, thyroid clearance of 131I was 13·0 ± 8·8 (s.d.) ml/min, and renal clearance was 20·6 ± 9·7 ml/min. In 205 healthy volunteers the 24 h 131I thyroid uptake averaged 13·8% and in 60·9% the uptake was less than 10% of the dose. Urinary excretion of 131I was correspondingly high. However, excretion of stable iodine in urine averaged only 62·0 μg/day. Thyroid secretion rate (TSR) calculated in a group of subjects with complete collection of urine was 12·0 μg I/day in women and 11·4 μg I/day in men. Protein-bound iodine (PBI) values in 50 subjects were 5·9 ± 1·3 μg/100 ml. Uptake of tri-iodothyronine by red blood cells also gave low values. The apparent discrepancy between low TSR and normal PBI is discussed. These findings, together with other reported values, indicate reduced thyroid activity in the tropics. It is argued that reduced metabolism is probably secondary to lower thyroid activity.
THE EFFECT OF PROLACTIN ON THE SLOUGHING CYCLE IN THE HYPOPHYSECTOMIZED—THYROIDECTOMIZED LIZARD, GEKKO GECKO L.
Authors: CHIU K. W. , PHILLIPS J. G.
Published: December 2008

Hypophysectomized—thyroidectomized geckos failed to slough during the experimental period of about 120 days. The resting phase of the sloughing cycle persisted so that the outer epidermal generation remained incomplete. These results indicate that one important endocrine component of the sloughing cycle is the normal functioning of the pituitary—thyroid system.

Prolactin administration at 0·4 i.u./g body wt on alternate days restored sloughing by reducing the length of the resting phase; the outer generation was completed and was shed after the appearance of a new inner unit.
DISTRIBUTION OF [131I]α1–24ADRENOCORTICOTROPHIN IN THE INTACT GUINEA-PIG
Authors: GOLDER MERIEL P. , BOYNS A. R.
Published: December 2008

Intact, unanaesthetized guinea-pigs were injected intravenously with [131I]α1–24adrenocorticotrophin (ACTH) (50–70 ng). The concentrations of radioactivity found in the kidney were considerably higher than in other tissues. There was no evidence for preferential accumulation in the adrenal gland as a whole when compared with 125I-labelled bovine albumin ([125I]BSA), [125I]poly-l-tyrosine and [125I]iodide. The intra-adrenal distribution of 131I radioactivity showed one peak at the border between the zona glomerulosa and the z. fasciculata and another in the z. reticulosa. The intra-adrenal distribution of [125I]BSA and [125I]iodide differed from that of [131I]α1–24ACTH.
ANALYSIS OF RIBOSOMES AND POLYSOMES DERIVED FROM RABBIT MAMMARY GLANDS DURING PREGNANCY AND LACTATION
Authors: HERRIMAN I. D. , BAIRD G. D. , BRUCE JUDY M.
Published: December 2008

Whole-ribosome and polysome-enriched fractions were prepared from the mammary glands of rabbits during late pregnancy and lactation. The composition of the fractions was determined by sucrose density gradient analysis and electron microscopy. The range of size of polysomal aggregates was similar in the late-pregnant and lactating gland, with aggregates containing five to nine ribosomal units predominating. However, the amount of polysomes relative to monosomes was invariably found to increase after parturition. The greater portion of this increase was accounted for by the increased abundance of aggregates containing five to nine units.
THE INFLUENCE OF LESIONS IN THE POSTEROVENTRAL GREY MATTER OF THE MID-BRAINS OF RATS ON SALT EXCRETION
Authors: GWYNNE H. L. , LOCKETT MARY F. , MARWOOD J. F.
Published: December 2008

Lesions in the posteroventral grey matter of the mid-brain reduced the ability of rats to excrete single oral saline loads and to adapt at normal speed to salt loading. Rats with these lesions had normal adrenal and thyroid function but stores of growth hormone in the adenohypophysis were reduced. Typical behavioural changes were induced: these included hyperactivity, almost frenzied blind running when disturbed which converted to perimeter running when obstructed by any object; hyperphagia and obesity. Effects on ability to handle salt loads are attributed to section of fibres ascending to the diencephalic centre in the posterior nuclei of the hypothalamus which influences salt balance.
EXTRATHYROIDAL EFFECT OF THIOCYANATE AND PROPYLTHIOURACIL: THE DEPRESSION OF THE PROTEIN-BOUND IODINE LEVEL IN INTACT AND THYROIDECTOMIZED RATS
Authors: LANGER P.
Published: December 2008

In rats to which 125I was administered for 28 days, the level of protein-bound 125I (PB125I) (estimated by trichloroacetic acid precipitation or filtration on a Sephadex G-25 column) was measured. In intact animals, after a single dose of 16 mg thiocyanate ion, a significant decrease of PB125I was found, which was inversely related to the level of thiocyanate in plasma. The decrease was much faster than that in rats after thyroidectomy. From these findings an extrathyroidal effect of thiocyanate was postulated and tested in rats fed 125I− for 28 days and then thyroidectomized immediately before the administration of a single dose of 16 mg thiocyanate ion or 15 mg propylthiouracil. The level of PB125I in most of the latter animals 4, 8, 18 and 24 h after the administration of the drugs was significantly lower than that in thyroidectomized controls.
INCREASE IN THYROTROPHIN SECRETION BY RAT PITUITARY AUTOGRAFTS AFTER INFUSION OF HYPOTHALAMIC EXTRACTS
Authors: EVANS J. S. , AVERILL R. L. W.
Published: December 2008

Thyroidal uptake and release of 131I were used to study the effects of prolonged infusion of porcine hypothalamic extract on the ability of rat pituitary autografts to secrete thyrotrophin (TSH). The extract used contained insufficient TSH to induce release of thyroidal 131I in hypophysectomized rats.

After infusion for 10 days, the time of maximal uptake of 131I and onset of 131I release was significantly shortened by infusion of hypothalamic, but not cerebral cortical extract, when compared with non-infused autografted controls. The rate of release of thyroidal 131I was significantly increased by the infusion of hypothalamic extract so that by 96–120 h after the administration of 131I the rate of release was not significantly different from that in intact controls.

Accelerated thyroidal release of 131I began 42–48 h after the application of hypothalamic extracts to pituitary autografts and fell rapidly after withdrawal of the extract. At the end of 14–17 days of infusion sections of the autografts contained aldehyde-fuchsin positive staining basophils.
THE SECRETION OF CORTISOL AND ITS MAMMARY UPTAKE IN THE GOAT
Authors: PATERSON J. Y. F. , LINZELL J. L.
Published: December 2008

In pregnant and in lactating goats the rate of cortisol secretion was measured by continuous intravenous infusion of tritium-labelled cortisol. Uptake of cortisol by the mammary gland was measured by simultaneous sampling of blood from the carotid artery and superficial epigastric vein, and measurement of mammary blood flow. In pregnant goats the rate of cortisol secretion was 9 μg/min but in preparturient and in lactating goats the rate was about 32 μg/min. There was a small but significant difference in cortisol concentration between the carotid artery and mammary vein. In pregnant goats the mammary uptake of cortisol was about 0·2 μg/min; this was increased to about 1·3 μg/min in preparturient and in lactating animals. Negligible quantities of cortisol were secreted in the milk.

Cortisol was administered by continuous infusion for 4 h into two lactating goats. Although there was some stimulation of milk secretion it seems likely that it resulted from a systemic rather than local action of cortisol.
LABOUR IN THE RABBIT: EFFECT OF ELECTRICAL STIMULATION APPLIED TO THE INFUNDIBULUM AND MEDIAN EMINENCE
Authors: LINCOLN D. W.
Published: December 2008

Labour was induced by electrical stimulation of the infundibulum and median eminence in the conscious prepartum rabbit. The stimulus was applied for 20 s through a chronically implanted platinum—rhodium electrode and consisted of 1 mA biphasic pulses at 50/s.

The first visible signs of labour occurred 1·5–3·0 min after stimulation and activity usually ceased within 25 min. This was sometimes sufficient for the delivery of the entire litter. The litters ranged from 5 to 11 pups. Frequently, labour ceased before all the young were expelled, but labour was easily restarted by a further period of stimulation. There were cases in which labour was restarted on more than four occasions before parturition reached completion. Parturition was sometimes left in a suspended state for more than 24 h. The viability of the pups was not adversely influenced by the protracted nature of such parturitions. Stimulation was most effective at inducing labour when applied close to the predicted time of parturition and the treatment was almost totally ineffective when applied more than 48 h before the predicted time. Nest-building was not precipitated by the premature birth of the young and sometimes occurred a day or more after parturition.

The stimulation parameters used for the induction of labour caused large milk-ejection responses when applied to the same animals during lactation. Some of these milk-ejection responses were equal to the release of more than 100 mu. oxytocin.

These results suggest that the rapid expulsion of the pups during natural labour in the rabbit could be the result of a sudden and very large release of oxytocin.
THE EFFECT OF HYPOPHYSIAL STALK-SECTION ON THE CORPUS LUTEUM OF THE GUINEA-PIG
Authors: ILLINGWORTH DOREEN V. , PERRY J. S.
Published: December 2008

The effects of hypophysial stalk-section on the growth and function of the corpus luteum of the non-pregnant guinea-pig have been compared with the effects of hypophysectomy (as previously described) and with the effects of prolactin administered to hypophysectomized animals. Stalk-section soon after ovulation did not impair the growth of the corpora lutea nor their ability to secrete progesterone. Stalk-section before day 9 of the oestrous cycle prevented the normal regression of the corpora lutea; they continued to grow and 3 weeks after ovulation were as large as those of pregnant animals, or of non-pregnant hysterectomized guinea-pigs. The corpora lutea regressed irregularly during the following 2 weeks. When performed on, or later than day 9, stalk-section did not prevent luteal regression at the normal time.

Administration of prolactin (10 i.u./day) to hypophysectomized guinea-pigs restored the growth-rate of the corpora lutea, which reached sizes comparable to those of the normal cycle, and those of stalk-sectioned animals, by 10 days after ovulation.

Our results indicate that prolactin can have substantial luteotrophic activity in the guinea-pig.
PROLACTIN PRODUCTION BY THE HUMAN ANTERIOR PITUITARY CULTURED IN VITRO
Authors: GALA R. R.
Published: December 2008

A pituitary was obtained from a patient with metastatic breast cancer and cultured for 81 days in Medium 199. The medium was changed every 3 days. The prolactin activity of the medium, as estimated by the local crop gland proliferation assay, was significantly lower in the first 3-day culture period than in subsequent periods. Prolactin activity was similar between days 6 and 21 of culture, decreasing to the limits of the bioassay system on the 27th day of culture. Analytical disc electrophoresis of the medium revealed the presence of a protein component which migrated behind human growth hormone (HGH). A densitometric analysis of the bands in disc electrophoresis showed that the protein concentration of the component migrating behind HGH correlated with the prolactin activity of the medium for later periods of culture. A calculation of the specific activity of this component gave a value of 125 i.u. prolactin/mg protein.
THE EFFECT OF INTRAVENOUS ALDOSTERONE ON ARTERIAL PRESSURE IN THE RABBIT AND ITS MODIFICATION BY VARIATIONS IN DIET
Authors: BURSTYN P. G. , HORROBIN D. F. , LLOYD I. J.
Published: December 2008

Thirty-nine decerebrate rabbits, curarized and maintained by artificial ventilation, were used in the experiments. In a control group which received only saline intravenous infusions, arterial pressure remained virtually unchanged for 6 h after decerebration. Three other groups were used, all of which received intravenous infusions of aldosterone starting 1 h after decerebration and continuing for 5 h: in these groups the pressure 1 h after decerebration was taken as 100%. In a group of animals which received a normal diet before the acute experiment, the mean percentage pressure rise at the end of 5 h of aldosterone infusion was 20·0 ± 2·3 (s.e.m.)%. In a group whose drinking water had been replaced with 1% NaCl solution, the mean percentage pressure rise after 5 h was 29·6 ± 3·2. In a group pretreated with a low salt intake, the mean percentage pressure rise after 5 h was 10·3 ± 2·8%. These results show that intravenous infusions of aldosterone at the rate of 6 μg/kg/h can raise arterial pressure in acute experiments, and that varying the sodium intake can alter the responsiveness of the cardiovascular system to the hypertensive action of aldosterone.
THE UPTAKE OF TRITIATED LYSINE VASOPRESSIN BY RAT AND PIG PITUITARY NEURAL LOBES IN VITRO
Authors: EDWARDS B. A.
Published: December 2008

Uptake of tritiated lysine vasopressin ([3H]LVP) was studied in halved neural lobes of rats (which had been given either tap water (control group) or 2% (w/v) NaCl solution as drinking water for 4 days) as well as in slices of pig neural lobe. Uptake of radioactivity into the neural lobes was shown but analysis of the extracts of incubated lobes of both species by ion exchange chromatography showed that very little of it remained in the tissue as hormone. In addition, some radioactivity was associated with trichloroacetic acid-insoluble proteins.

After 90 min of incubation, and after correction for the breakdown, the uptake of unchanged [3H]LVP, expressed as a tissue: medium ratio, was 0·14 ± 0·04 and 0·09 ± 0·03 (mean ± s.e.m.) for the saline-treated and control rats respectively, while the tissue: medium ratios for the breakdown product(s) were 6·47 ± 0·45 and 5·50 ± 0·36. The results suggest uptake of [3H]LVP into the cell with almost complete intracellular breakdown of the hormone.
THE EFFECT OF PINEAL METHOXYINDOLES ON RAT VAGINAL OPENING TIME
Authors: COLLU R. , FRASCHINI F. , MARTINI L.
Published: December 2008

Melatonin and 5-methoxytryptophol, the two methoxyindoles of pineal origin, were injected into a lateral ventricle of the brain of immature female rats. Treatment was started on the 25th day of age and terminated when the vagina opened. The injection of both methoxyindoles resulted in a statistically significant delay in vaginal opening. Since previous experiments had shown that melatonin specifically inhibits secretion of luteinizing hormone and that 5-methoxytryptophol specifically blocks release of follicle-stimulating hormone, the present results support the hypothesis that the onset of sexual maturation needs a balanced secretion of both gonadotrophins.
CYTOLOGICAL CHANGES IN THE MOUSE ANTERIOR PITUITARY AFTER NEONATAL THYMECTOMY: A LIGHT AND ELECTRON MICROSCOPICAL STUDY
Authors: BIANCHI ELENA , PIERPAOLI W. , SORKIN E.
Published: December 2008

A detailed light and electron microscope examination of the anterior pituitary gland of mice at different times after neonatal thymectomy was performed. Neonatal removal of the thymus resulted in a progressive increase in the number of somatotrophic hormone-producing cells showing characteristic changes represented by extremely distended cisternae of the endoplasmic reticulum and reduction in the number of hormone granules. These modifications were not observed in sham-operated controls or in neonatally splenectomized mice. The functional significance of these changes in relation to thymectomy and the significance of somatotrophic hormone for the development of the thymus and for immunological maturation is discussed. It is suggested that somatotrophic hormone and possibly other hormones determine certain specific steps of differentiation of precursor cells to immunocompetent cells and that the thymus is an endocrine target gland of somatotrophic hormone.
TESTOSTERONE BIOSYNTHESIS IN THE DESERT MOUSE, ACOMYS CAHIRINUS
Authors: BEDRAK E. , SAMOILOFF V. , FINKELSTEIN Z.
Published: December 2008

Testosterone synthesis was studied in Acomys cahirinus by incubation of its testis with radioactive substrates. In comparison with other rodents, the Acomys testis was found to have a lower 17β-hydroxysteroid oxidoreductase activity, whereas the activity of 20α-hydroxysteroid oxidoreductase was high. The accumulation of 5-ene-3β-hydroxy metabolites suggested that biosynthesis proceeded preferentially by the 4-ene route. This was confirmed by the simultaneous incubation of [3H]5-ene-3β-hydroxysteroids and [14C]4-en-3-oxosteroids. The predominant route of biosynthesis would, therefore, appear to be: pregnenolone → progesterone → 17α-hydroxyprogesterone → androstenedione → testosterone.
IMMUNOASSAY OF HUMAN LUTEINIZING HORMONE USING UNIVALENT RADIOACTIVE ANTIBODIES
Authors: MILES L. E. M. , HARTREE ANNE STOCKELL
Published: December 2008

Univalent antibody fragments were isolated from a papain-digested antiserum to human chorionic gonadotrophin. The univalent antibody fragments were purified, iodinated with 125I and used in a sensitive immunoradiometric assay of human luteinizing hormone. Unlike intact divalent antibodies, the univalent radioactive antibody fragments cannot simultaneously bind to both soluble antigen and antigen-immunoadsorbent.
THE ACTIVITY OF HUMAN FOLLICLE-STIMULATING HORMONE PREPARATIONS AS MEASURED BY A RESPONSE IN VITRO
Authors: RYLE MARGARET
Published: December 2008

Experiments were carried out with two highly purified preparations of human follicle-stimulating hormone (FSH), of pituitary and urinary origin. The uptake of [3H]thymidine was used to measure the response of cultured infantile mouse ovaries. The activity of the pituitary FSH did not decline during 7 days' incubation in the standard culture conditions, nor was it reduced by the culture of infantile mouse ovaries in it. It did not stimulate increased thymidine uptake during the 1st day of culture. Thereafter the rate of thymidine uptake per ovary in response to pituitary FSH remained constant until the end of the 4-day culture period. The urinary FSH became progressively less effective after the 2nd day of incubation. The two preparations gave highly significant linear log dose—response curves in the range 0·01 to 0·64 i.u./ml. The results are discussed in relation to the mode of action of FSH.
INVOLVEMENT OF THE MACROPHAGE SYSTEM IN THE INVOLUTION OF THE MAMMARY GLAND IN THE ALBINO RAT
Authors: RICHARDS R. C. , BENSON G. K.
Published: December 2008

Adult female rats undergoing their first lactation were experimentally weaned by removing their pups on day 4 of lactation. The macrophages of the mammary gland were labelled with trypan blue or horseradish peroxidase. Treatment with trypan blue showed the macrophages to be present in the connective tissue stroma from the 4th day of lactation to the 5th day of involution. However, on day 6 of involution they were congregated around the remaining islets of alveoli. Other cells which took up the dye were found in the epithelium of the alveoli. They were few in number on day 4 of lactation, increased numerically during the first 2 days of involution, and decreased again by day 6 of involution. Since they took up the dye in a similar manner to the lymphocytes of the regional lymph node, it is believed that they were lymphocytes. Treatment with ICI 46,474 in no way affected the course of mammary involution up to day 6. Treatment with horseradish peroxidase on day 4 of lactation or day 2 of involution resulted in labelling of the macrophages, which were found scattered in the stroma. However, by the 4th and 6th day of involution the macrophages were found to a greater extent in and around the remaining islets of alveoli.
DNA POLYMERASE ACTIVITY IN MAMMARY GLAND OF VIRGIN MICE AFTER OVARIAN HORMONE TREATMENT
Authors: BANERJEE D. N. , BANERJEE M. R. , WAGNER JANICE
Published: December 2008

The effect of ovarian hormones on DNA polymerase activity in the mouse mammary gland was determined. The rate of [3H]thymidine triphosphate incorporation into DNA during incubation in vitro was used as a measure of DNA polymerase activity in the post-microsomal supernatant fraction of the mammary tissue. A negligible amount of DNA polymerase activity was present in the mammary tissue of ovariectomized mice which had no hormone treatment. Daily subcutaneous injections of 1 μg oestradiol-17β plus 1 mg progesterone induced a sixfold increase of DNA polymerase activity in the mammary tissue after two injections. A single intraperitoneal injection of the same dose also induced a similar rise of DNA polymerase activity and the effect was evident within hours after the treatment. The results provide evidence that stimulation of cellular biosynthesis by the growth-promoting ovarian hormones is associated with the activation of a specific enzyme involved in DNA replication.
ANALYSIS OF MILK SECRETED SPONTANEOUSLY BY VIRGIN RATS BEARING INDUCED MAMMARY TUMOURS
Authors: HALLOWES R. C. , LEWIS DOREEN J.
Published: December 2008

Biochemical and immunological studies were performed on milk secreted spontaneously by 1-yr-old virgin female Sprague—Dawley rats. They had received 30 mg 9,10-dimethyl-1,2-benzanthracene when 50 days old and most had mammary gland tumours. No milk secretion was found specifically in any of these tumours. The fat content of the secretion was twice that of post-partum milk and slight differences were demonstrated in the saturated fatty acid composition. The protein concentration was doubled but both casein and milk plasma proteins were identical to those of post-partum milk. The lactose concentration was one quarter that of post-partum milk but similar milk specific carbohydrates were present. Lactate dehydrogenase isoenzymes were quantitatively similar in each. It was shown that the secretion by virgin rats closely resembled post-partum milk.
EFFECTS OF VOLUME AND DISTRIBUTION OF MILK ON THE OXYTOCIN-INDUCED CONTRACTION OF THE LACTATING RAT MAMMARY GLAND IN VIVO
Authors: DeNUCCIO D. J. , GROSVENOR C. E.
Published: December 2008

Milk was added intraductally in 0·2 ml increments to previously emptied mammary glands in rats. Direct microscopic observations of the glands showed that each increment of milk did not distribute evenly either within a single lobule or among lobules. Increase of the intramammary pressure either by i.v. injection of oxytocin or by compression of the gland between thumb and forefinger, distributed the milk more evenly within the gland. These observations led to the routine injection of 1·6–3·2 mu. oxytocin in order to distribute each increment of milk evenly throughout the gland. The intramammary pressure response of the gland to different doses of oxytocin was then determined. The rises in intramammary pressure above equilibrium pressure in response to 0·8 and 1·6 mu. oxytocin increased fourfold on average with increasing gland volume over the compliant portion of the static pressure-volume curve. The slopes of the dose oxytocin-intramammary pressure response lines became progressively steeper and shifted to the left as the volume of the mammary gland increased, indicating a progressive reduction in the dose of oxytocin required to elicit a given response. No differences were noted between rats lactating for 9–13 days and those lactating for 20–24 days. In a related study the duct system of the rat gland was found to contain little fluid even after 8 h of non-suckling, though it became filled swiftly after a single i.v. injection of oxytocin. Non-suckling for 16–24 h was required to overcome passively the resistance to entry of milk from the alveoli.