scholarly journals Artificial Induction of Lactation in Cattle by Use of Dexamethasone Trimethylacetate

1975 ◽  
Vol 28 (2) ◽  
pp. 183 ◽  
Author(s):  
WJ Fulkerson ◽  
GH McDowell
Keyword(s):  
Mammary Glands ◽  
Essentially Normal ◽  
Artificial Induction ◽  
Oestradiol Benzoate

Injections of dexamethasone trimethylacetate initiated lactation in nulliparous Ayrshire heifers previously given a series of injections of oestradiol benzoate plus progesterone to develop mammary glands. Essentially normal lactation occurred following injection of 20 mg/day dexamethasone for 3 days, whereas injection of 40 mg/day for 4 days initiated secretion of smaller volumes of milk-like fluid containing relatively high levels of lipid. Milking alone failed to initiate lactation.

scholarly journals Artificial Induction of Lactation in Ewes: The Role of Prolactin

1975 ◽  
Vol 28 (6) ◽  
pp. 525 ◽  
Author(s):  
WJ Fulkerson ◽  
GH McDowell ◽  
LR Fell
Keyword(s):  
Subcutaneous Injection ◽  
Mammary Glands ◽  
Subcutaneous Injections ◽  
Intravenous Injections ◽  
Artificial Induction ◽  
Oestradiol Benzoate

The mammary glands of 30 non-pregnant, intact ewes were developed by subcutaneously injecting oestrogen plus progesterone at intervals of 3 days from day 0 to day 27. Two days later (day 29), 15 ewes were injected subcutaneously with 18 mg ergocryptine, to inhibit specifically secretion of prolactin. Then groups of ewes, each comprising five ergocryptine-treated and five untreated ewes, were injected from days 30 to 34 with either four intravenous injections each day of 1 i.u. syntocinon, one subcutaneous injection each day of 10 mg dexamethasone trimethylacetate, or two subcutaneous injections each day of 2� 5 mg oestradiol benzoate plus 6�25 mg progesterone. All ewes were milked by hand on days 30-50. Within 24 h of injecting ergocryptine, levels of prolactin in serum were reduced to negligible values ( < 2 ng/ml).

SENSITIVITY OF ANTERIOR HYPOTHALAMIC AREAS TO GONADAL STEROID IMPLANTATION IN ANDROGENIZED FEMALE RATS

1977 ◽  
Vol 74 (2) ◽  
pp. 315-NP ◽  
Author(s):  
A. DANGUY ◽  
J. L. PASTEELS ◽  
F. ECTORS
Keyword(s):  
Single Injection ◽  
Mammary Glands ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Male Rats ◽  
Control Synthesis ◽  
Normal Female ◽  
Immunofluorescence Studies ◽  
Oestradiol Benzoate ◽  
Stimulation Of

A single injection of 1 mg of a complex of testosterone esters on day 5 of life was used to prepare constantly oestrous rats. Such androgenized female rats were then ovariectomized and submitted to stereotaxical implantation of 1 μg oestradiol benzoate, 5 μg testosterone isobutyrate or, as a control, 10 μg cholesterol in the anterior hypothalamic areas. The effects of the steroids on plasma and pituitary FSH and LH were assessed by radioimmunoassay. As reported previously by us in normal female and male rats, the preoptic–suprachiasmatic area (POA) was able to control synthesis and secretion of both gonadotrophins and did not lose its sensitivity to oestradiol and testosterone in androgenized rats. Evidence for enhanced prolactin secretion in androgenized rats was derived from immunofluorescence studies of the pituitary gland and from histology of the mammary glands. In this respect the condition of the androgenized females was opposite to that of the males. The present work demonstrated that stimulation of prolactin secretion in androgenized female rats resulted from oestrogen action due to permanent oestrus rather than from impairment of hypothalamo-hypophysial relationships. Indeed, prolactin stimulation was suppressed when the androgenized rats were ovariectomized and restored when they were subsequently implanted with oestradiol in the POA.

scholarly journals Artificial Induction of Lactation in Ewes: The Relative Importance of Oxytocin and the Milking Stimulus

1975 ◽  
Vol 28 (6) ◽  
pp. 521 ◽  
Author(s):  
WJ Fulkerson ◽  
GH McDowell
Keyword(s):  
Mammary Glands ◽  
The Other ◽  
Relative Importance ◽  
Artificial Induction ◽  
Group A ◽  
Group B

Eight ovariectomized and four intact ewes were given oestrogen plus progesterone to develop the mammary glands. The intact ewes (group A) and four ovariectomized ewes (group B) then received four injections each day of 1 i.u. syntocinon for 5 days whereas the other four ovariectomized ewes (group C) received placebo injections of 0�9 % saline. Milking commenced the day after the last of these injections.

EFFECT OF PROLACTIN INHIBITORY AGENTS ON THE ECTOPIC ANTERIOR PITUITARY AND THE MAMMARY GLAND IN RATS

1977 ◽  
Vol 85 (2) ◽  
pp. 267-278 ◽  
Author(s):  
K.-J. Gräf ◽  
R. Horowski ◽  
M. F. El Etreby
Keyword(s):  
Mammary Gland ◽  
Anterior Pituitary ◽  
Direct Action ◽  
Mammary Glands ◽  
Female Rats ◽  
Simultaneous Administration ◽  
Dopaminergic Receptors ◽  
Oestradiol Benzoate ◽  
Biological Effectiveness ◽  
Inhibitory Agents

ABSTRACT The purpose of the present study was to investigate the biological effectiveness of two highly potent prolactin (PRL) inhibitors, lisuride hydrogen maleate (LMH) and 2-Br-α-ergocryptine (CB-154), in the absence of hypothalamic factors acting directly at the level of the anterior pituitary. Hypophysectomized female rats bearing 4 transplanted pituitaries beneath the kidney capsules were treated with oestradiol benzoate (OeB) and progesterone (P) with or without simultaneous administration of LHM or CB-154 for 22 days in order stimulate or inhibit lobulo-alveolar growth of the mammary glands. In addition to the investigation of the mammary glands by DNA determination and assessment of the histological pictures, the aim of this study was directed towards the influence of the substances tested at the level of the anterior pituitary remote from the hypothalmus. In this connection the changes in the different cells within the ectopic pituitaries as revealed by immunoenzyme-cytochemical studies were investigated. The results obtained support the classical view of a neuroendocrine regulation of mammary gland growth and the importance of oestrogens, P and PRL within this system. Both ergot derivatives LHM and CB-154 were able to antagonize the stimulatory effect of OeB combined with P on the mammary gland. With regard to the mechanism of action of LHM and CB-154 it is concluded that both substances act via a direct action on dopaminergic receptors within the ectopic anterior pituitary.

scholarly journals Artificial Induction of Lactation in Ewes: The Use of Prostaglandin

1977 ◽  
Vol 30 (6) ◽  
pp. 573 ◽  
Author(s):  
WJ Fulkerson ◽  
GH McDowell ◽  
RD Hooley ◽  
LR Fell
Keyword(s):  
Mammary Glands ◽  
Transient Increase ◽  
Artificial Induction

Injections of an analogue of prostaglandin F2Cl (T.F.lO!) initiated secretion of copious amounts of fluid resembling normal ovine milk when given to non-pregnant ewes with developed mammary glands. Injections of T.F.101 elicited a substantial but transient increase in the levels of prolactin in plasma. Results for intact and ovariectomized ewes were similar.

EFFECTS OF OESTROGEN AND/OR PITUITARY GRAFTS ON NUCLEIC ACID SYNTHESIS IN THE MAMMARY GLANDS OF LACTATING MICE

1978 ◽  
Vol 77 (3) ◽  
pp. 319-323 ◽  
Author(s):  
HIROSHI NAGASAWA ◽  
REIKO YANAI
Keyword(s):  
Mammary Gland ◽  
Dna Synthesis ◽  
Anterior Pituitary ◽  
Acid Synthesis ◽  
Mammary Glands ◽  
Low Level ◽  
Oestradiol Benzoate ◽  
Pituitary Glands ◽  
Gland Function ◽  
And Function

The mammary gland synthesizes little DNA during lactation in mice. The effects of daily injections of oestradiol benzoate (OB) between days 9 and 11 of lactation, and/or grafting with three isologous anterior pituitary glands on day 1, on the growth of the litter and the development and function of mammary glands were studied on day 12 of lactation in C3H/He mice. The level of prolactin in the plasma of mice with pituitary grafts was raised, but mammary gland function was not affected. The synthesis and content of mammary gland RNA was depressed after injection of 0·5 μg OB/day; at a dose of 10 μg/day, OB also depressed litter growth and mammary DNA content, but increased the synthesis of DNA and the level of prolactin in the plasma. Pituitary grafting enhanced the effect of 10 μg OB/day on DNA synthesis. These findings suggest that one of the causes of the low level of DNA synthesis in the mammary gland during lactation in mice is a low level of oestrogen in the circulation.

IN VIVO OBSERVATIONS OF THE SEMINAL VESICLES OF CASTRATED RATS AND THE RESPONSES TO VARIOUS STEROIDS

1960 ◽  
Vol XXXIII (III) ◽  
pp. 411-416
Author(s):  
Jerome A. Grunt ◽  
Joseph E. Walker
Keyword(s):  
Testosterone Propionate ◽  
Seminal Vesicles ◽  
Sesame Oil ◽  
Double Blind Study ◽  
Double Blind ◽  
Subcutaneous Injections ◽  
Small Vessels ◽  
Essentially Normal ◽  
Oestradiol Benzoate

ABSTRACT In a study of seminal vesicle reactivity to a number of steroids, young adults rats were castrated and 14 days later were started on 7 daily subcutaneous injections of 0.1 ml sesame oil, with or without an added steroid. Ten groups containing 7 to 12 animals each were established: 1) sesame oil; 2–4) 10 μg, 50 μg and 100 μg testosterone propionate; 5–6) 10 μg and 500 μg oestradiol benzoate; 7–8) 100 μ and 500 μg progesterone; 9–10) 100 μg and 500 μg corticosterone. After the course of injections the seminal vesicles were studied by the quartz rod transillumination method of Knisely. The investigation was carried out as a »double-blind study«; one investigator recording his observations without knowledge of the treatment. Following castration there was a marked decrease in the number of small vessels, a derangement of the vascular pattern and a slowing of the rate of blood flow. There were also changes in tissue transparency and granularity and an increase in spontaneous, rhythmic contractions of the vesicles. Treatment with oestradiol benzoate, progesterone, corticosterone, and 10 μg testosterone propionate appeared to cause no alteration in the vesicle of the castrate. Vesicles of animals injected with 50 μg of testosterone propionate had essentially normal vasculature and parenchyma but continued to contract rhythmically, while those treated with 100 μg of testosterone propionate had vesicles restored to normal in every way but size.

ARTIFICIAL INDUCTION OF LACTATION IN EWES

1974 ◽  
Vol 63 (1) ◽  
pp. 167-173 ◽  
Author(s):  
W. J. FULKERSON ◽  
G. H. McDOWELL
Keyword(s):  
Normal Pregnancy ◽  
Daily Injection ◽  
Milk Secretion ◽  
Artificial Induction ◽  
Oestradiol Benzoate

SUMMARY Lactation was induced in non-pregnant, intact ewes. The injection of 60 mg progesterone plus 240 μg oestradiol benzoate every third day for 60 days increased udder size. Subsequent daily injection of 10 mg dexamethasone trimethylacetate or 5 mg oestradiol benzoate plus 12·5 mg progesterone for 6 days led to further udder development and initiated secretion of fluid similar in appearance and composition to normal ovine milk. Both treatments were equally effective in initiating milk secretion and subsequent production (approximately 0·50 kg/day) was similar to that of ewes lactating after normal pregnancy [0·59 ± 0·06 (s.e.m.) kg/day]. Glands of ewes receiving no treatment other than milking after oestrogen and progesterone priming remained small in size and produced only trivial volumes of secretion when milked out daily for 14 days.

Artificial induction of lactation in unmated heifers and in heifers with reproductive abnormalities

1979 ◽  
Vol 19 (96) ◽  
pp. 13
Author(s):  
DE Field ◽  
GH McDowell ◽  
RJ Buesnel ◽  
TM Jessep
Keyword(s):  
Dairy Cows ◽  
Milk Fat ◽  
Mammary Glands ◽  
Reproductive Capacity ◽  
Milk Secretion ◽  
Subcutaneous Injections ◽  
Priming Phase ◽  
Artificial Induction ◽  
Suitable Treatment ◽  
The Mean

Six unmated heifers and six heifers with reproductive abnormalities were induced to lactate artificially. Mammary glands were developed with a series of subcutaneous injections of oestrogen plus progesterone over either 30 or 60 days (priming phase) prior to triggering milk secretion with injections of dexamethasone trimethylacetate. All twelve heifers commenced lactation and the composition of their milk was similar to that of heifers lactating after calving, with the exception that the fat content was consistently high for heifers induced to lactate artificially (ca 4.1% and ca 5.3% respectively). Yields of milk and milk fat for heifers primed for 30 and 60 days, respectively, were not significantly different (P > 0.05) over the first five months of lactation. During this period, the mean milk yield of heifers induced to lactate artificially was 55% and 71%, and their mean yield of fat was 69% and 87% of corresponding yields for heifers lactating after normal and advanced calving, respectively. The hormone treatments did not correct reproductive abnormalities in heifers with aberrant reproductive capacity, neither did they impair reproductive capacity in 'normal' heifers. It appears that a suitable treatment for inducing lactation artificially in non-pregnant dairy cows would be to use a priming phase of 30 days followed by a trigger phase of 3 days.

Basal Lamina Formation in DMBA Induced Mammary Carcinoma

1977 ◽  
Vol 35 ◽  
pp. 534-535
Author(s):  
I. Russo ◽  
J. Saby ◽  
J. Russo
Keyword(s):  
Mammary Carcinoma ◽  
Virgin Female ◽  
Mammary Glands ◽  
Sesame Oil ◽  
Female Rats ◽  
Ultrastructural Changes ◽  
Post Inoculation ◽  
Intermediate Type ◽  
Sprague Dawley ◽  
Intercellular Spaces

It has been previously demonstrated that DMBA-induced rat mammary carcinoma originates in the terminal end bud (TEB) of the mammary gland by proliferation of intermediate type cells (1). The earliest lesion identified is the intraductal proliferation (IDP), which gives rise to intraductal carcinomas. These evolve to cribriform, papillary and comedo types (2). In the present work, we report the ultrastructural changes that take place in the IDP for the formation of a cribriform pattern.Fifty-five-day-old Sprague Dawley virgin female rats were inoculated intra- gastrically with 20 mg 7,12-dimethylbenz(a)anthracene (DMBA) in 1 ml sesame oil. Non-inoculated, age-matched females were used as controls. Mammary glands from both control and experimental rats were removed weekly from the time of inoculation until 86 days post-inoculation. The glands were fixed and processed for electron microscopy (2).The first change observed in IDP's was the widening of intercellular spaces and the secretion of an electron dense material into these spaces (Fig. 1).

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