Disease relevance of PRL

• For the purpose of obtaining an integral picture of anterior pituitary function in canine pituitary-dependent hyperadrenocorticism (PDH), 47 dogs with PDH and eight control dogs received combined administration of four hypophysiotropic hormones (CRH, GHRH, GnRH and TRH) and measurements were made of ACTH, cortisol, GH, LH, PRL and TSH [1].
• Sperm count decreased to azoospermia in 3 months after PRL administration with decrease of sperm motility and increase of abnormal forms [2].
• Thereby, the role of prolactin in the winter fur growth and the initiation of testicular recrudescence, if it is truly involved, is manifested through its decreasing secretion rather than the actual blood concentrations [3].
• The effect of prolactin on canine pancreatic secretion. Implications on the pathogenesis of the pancreatitis of pregnancy [4].
• Intracerebral hemorrhage occurred in 14% of day 1 animals, 68% of untreated animals on day 3, and 15% of the group treated with prolactin [5].

Psychiatry related information on PRL

• Individual differences in sensitivity to PRL as well as the existence of molecular variants of canine PRL with different bioactivity versus immunoreactivity ratios may help clarify the aetiopathology of PSC [6].
• In 2 out of 8 dogs a negative correlation between serum progesterone and prolactin levels was found at Day 11 and Day 15, respectively (Day 0 = first day of copulation) [7].

High impact information on PRL

• Of the hormones tested, only insulin was strongly hepatotrophic; T3 had a minor effect, and glucagon, prolactin, angiotensin II, vasopressin, norepinephrine and estradiol were inert [8].
• Insulin and glucose levels were higher, LH and PRL levels were unaltered, and T4 levels were marginally lower; the levels of each of these hormones remained within the normal ranges for dogs throughout the experiment [9].
• Blood was collected for 8 h posttreatment and assayed for GH, cortisol, ACTH, aldosterone, PRL, insulin, T3, and T4 [10].
• Aldosterone, PRL, T3, and T4 were not significantly affected after L-692,429 administration; however, ACTH treatment significantly increased aldosterone (P < 0.05) [10].
• The concentrations of progesterone (P), relaxin (Rlx), estradiol (E2) and PRL were measured by specific RIAs in serum samples collected twice daily at 8:00 am and 3:00 pm at weekly intervals after mating and until whelping in five Labrador Retriever bitches [11].

Chemical compound and disease context of PRL

• There seems to be a good possibility that hyperprolactinemia causes impotence, at least partially via some intrinsic property of prolactin (PRL), rather than through its suppressive effects on the hypothalamic-pituitary-gonadal testosterone dynamics [12].
• BMY-25801 failed to reveal any D2-dopamine receptor antagonist properties in several pharmacological tests (catalepsy, apomorphine stereotypy, serum prolactin, striatal dihydroxyphenylacetic acid and [3H]spiperone displacement) whereas metoclopramide was uniformly active in these tests [13].
• A dopamine agonist, cabergoline, known for its prolactin secretion inhibitory effects, was injected subcutaneously at a dose of 5 micrograms/kg body weight in five pregnant and five nonpregnant Beagle bitches [14].
• In order to determine whether this shortening results from decreased prolactin release or is due to another dopamine agonistic effect on the pulsatile release of FSH and LH, eight anoestrous beagle bitches were treated with a low dose of the serotonin antagonist metergoline (0.1 mg per kg body weight, twice daily) starting 100 days after ovulation [15].
• Serum levels of follicle stimulating hormone, luteinizing hormone, prolactin, testosterone, 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha, 17 beta-diol, 5 alpha-androstane-3 beta, 17 beta-diol, and 17 beta-estradiol from male beagles with spontaneous or induced benign prostatic hyperplasia [16].

Biological context of PRL

• Intravenous AVT produced an antidiuresis, kaliuresis and inconsistent natriuresis, independently of changes in GFR, blood pressure, heart rate and plasma PRL [17].
• In dogs with PDH the responses to combined hypophysiotropic stimulation, measured as increment and area under the curve (AUC), were not different for ACTH, lower for GH and TSH (increments and AUC) and higher for cortisol (increments), LH (AUC, n = 25 noncastrated dogs) and PRL (increments and AUC) than in controls [1].
• The effects of arginine vasotocin (AVT), 4-6 ng/kg, on renal function and plasma prolactin (PRL) were determined in conscious American foxhounds undergoing a water diuresis [17].
• Basal PRL concentrations of dogs with benign or malignant lesions were not found to be elevated in comparisons controlled for the effects of estrous cycle phase or progestin treatment [18].
• As an experiment to elucidate the canine luteal function maintenance system, a PGF2alpha-analogue, fenprostalene (PGF-F), was administered 24 and 54 days after ovulation to induce luteal regression, and the responses of luteinizing hormone (LH) and prolactin (PRL), which are considered to support the canine corpus luteum, were investigated [19].

Anatomical context of PRL

• The immunoperoxidase technique was used to study functional cell types in the pars distalis of the pituitary gland and to detect growth hormone (GH) and prolactin (PRL) target sites in the prostate gland [20].
• This correlates well with an increase in PRL-dependent staining in glandular epithelium and fibromuscular tissue of the prostate gland [20].
• Regardless of the structural type of the progestagens tested and the presence of mammary gland enlargement, serum PRL and GH levels were not clearly enhanced [21].
• In this work, we investigated the effect of a synthetic glucocorticoid dexamethasone (DEX) and PRL on the paracellular barrier function in MDCK renal epithelial cells [22].
• Similarly, the immunoenzyme-cytochemical investigations of the anterior pituitary gland after treatment with CPA showed the PRL cells to be unaffected [21].

Associations of PRL with chemical compounds

• In both age groups, the GHSs were specific for GH release as they did not cause significant elevations in the plasma concentrations of ACTH, cortisol, TSH, LH, and PRL [23].
• These results suggest that PRL and GH directly and specifically produced contraction of the corpus cavernosum penis, resulting in erectile insufficiency, and that the effect of PRL is partially mediated by prostaglandin [12].
• Pretreatment with indomethacin (10(-5) M.), but not tetrodotoxin (10(-5) M., partially suppressed (p < 0.05) the effects of PRL [12].
• Elevations in cerebral osmolality did not result in changes in circulating levels of LH or PRL which qualitatively differed from levels of these hormones recorded during IC infusions of 0.9% NaCl [24].
• The present study investigates the levels of the following hormones in serum and in tissue homogenates in dogs bearing canine mammary tumours: prolactin (PRL), progesterone (P4), dehydroepiandrosterone (DHEA), androstenedione (A4), testosterone (T), 17beta-estradiol (17beta-E2) and estrone sulfate (S04E1) [25].

Regulatory relationships of PRL

• It is not known whether relaxin can stimulate prolactin secretion in dogs [26].

Other interactions of PRL

• We, therefore, sought to determine the effects of daily treatment with the DA receptor antagonist, domperidone (DOM), on secretion of the POMC peptides adrenocorticotropic hormone (ACTH) and alpha-melanocyte-stimulating hormone (alpha-MSH) from the dog pituitary, and on concentrations of another pituitary hormone regulated by DA, prolactin (PRL) [27].
• Effects of acute and repeated intravenous administration of L-692,585, a novel non-peptidyl growth hormone secretagogue, on plasma growth hormone, IGF-1, ACTH, cortisol, prolactin, insulin, and thyroxine levels in beagles [28].
• Histamine, 2-methylhistamine and 4-methylhistamine had no statistically significant effect on plasma renin activity, blood pressure, or heart rate, and histamine had no effect on plasma prolactin concentration [29].
• Six pregnancies were terminated in mid-gestation with aglépristone, a progesterone receptor antagonist, in 5 beagle bitches in order to determine the effects of aglépristone on plasma concentrations of prolactin and progesterone, the duration of the luteal phase, and the interestrous interval [30].

Analytical, diagnostic and therapeutic context of PRL

• PRL, GH, or PL in the perfusion medium [12].
• Homologous radioimmunoassays for estimation of serum canine GH and PRL concentrations were also performed [20].
• At eight weeks after hypophysectomy basal plasma ACTH, cortisol, GH, LH, PRL, and TSH concentrations were significantly lower than before surgery [31].
• In the combined anterior pituitary function test there were no plasma GH, LH, PRL, and TSH responses to stimulation, whereas plasma ACTH and cortisol responses were small but significant [31].
• Pooled sera from covertly (CTRL) and overtly pseudopregnant (PSPT) diestrous bitches with high or low (> 10 or < 10 ng x mL(-1), respectively) serum PRL (measured by ELISA) were analyzed by Sephadex G-100 and Concanavalin A-Sepharose column chromatography [32].

References