+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Prolactin secretion after hypothalamic deafferentation in beef calves: response to haloperidol, alpha-methyl-rho-tyrosine, thyrotropin-releasing hormone and ovariectomy



Prolactin secretion after hypothalamic deafferentation in beef calves: response to haloperidol, alpha-methyl-rho-tyrosine, thyrotropin-releasing hormone and ovariectomy



Animal Reproduction Science 111(1): 54-68



In ruminant species photoperiod regulates prolactin (PRL) secretion. It is hypothesized that the inhibition of PRL secretion resides in dopaminergic neurons of the medial basal hypothalamus (MBH). To test this hypothesis, anterior (AHD), posterior (PHD) and complete (CHD) hypothalamic deafferentation and sham operation control (SOC) surgeries were carried out during May (long-day photoperiod) in beef heifer calves (6-8 mo old) to measure basal PRL secretion and PRL secretion as affected by intravenous secretagogues. On the day of surgery (day 0), PRL secretion reflected stress of anesthesia and surgery in all groups. Thyrotropin-releasing hormone (TRH), alpha-methyl-rho-tyrosine (alphaMrhoT), and haloperidol (HAL) was iv injected on days 11, 13 and 15, respectively. AHD, PHD, CHD, and SOC calves responded to TRH (100 microg) with an acute increase in PRL that peaked within 20 min. All heifers responded to alphaMrhoT (10 mg/kg BW) with an acute elevation in PRL within 10 min and remaining elevated for 3 h. HAL (0.1 mg/kg BW) induced an acute increase in PRL secretion in all groups, peaking within 15-30 min. Seven months later (December, short-day photoperiod) these heifers were ovariectomized. Basal plasma PRL levels were seasonally low, PRL secretion in AHD, PHD and CHD animals abruptly increased within 15 min to iv injection of 100 microg TRH to a greater amount than seen in SOC heifers. Although a biphasic effect on PRL secretion entrains under long-day and short-day photoperiods, hypothalamic deafferentation in cattle did not affect the pituitary gland's responsiveness to secretagogues.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 055222829

Download citation: RISBibTeXText

PMID: 18359173

DOI: 10.1016/j.anireprosci.2008.02.003


Related references

Pulsatile growth hormone, prolactin, and thyrotropin secretion in rats with hypothalamic deafferentation. Brain Research 127(1): 137-152, 1977

Growth serum growth hormone thyroxine prolactin and insulin in calves after thyrotropin releasing hormone or 3 methyl thyrotropin releasing hormone. Journal of Animal Science 44(3): 422-430, 1977

Growth, Serum Growth Hormone, Thyroxine, Prolactin and Insulin in Calves after Thyrotropin Releasing Hormone or 3-Methyl-Thyrotropin Releasing Hormone. Journal of Animal Science 44(3): 422-430, 1977

The effects of anterior hypothalamic deafferentation on thyrotropin (TSH) biosynthesis and response to TSH-releasing hormone. Endocrinology 118(6): 2417-2424, 1986

Differential ability of thyrotropin-releasing hormone and N3im-methyl-thyrotropin-releasing hormone to affect prolactin and thyrotropin production in primary rat pituitary cell cultures. Endocrinology 106(1): 107-112, 1980

Dose-response of prolactin and thyrotropin to N3im-methyl-thyrotropin releasing hormone in euthyroid men. Journal of Clinical Endocrinology and Metabolism 43(4): 856-860, 1976

Effects of hypothalamic dopamine on growth hormone-releasing hormone-induced growth hormone secretion and thyrotropin-releasing hormone-induced prolactin secretion in goats. Animal Science Journal 86(6): 634-640, 2015

Effects of starvation in rats on serum levels of follicle stimulating hormone, luteinizing hormone, thyrotropin, growth hormone and prolactin; response to LH-releasing hormone and thyrotropin-releasing hormone. Endocrinology 100(2): 580-587, 1977

Plasma luteinizing hormone follicle stimulating hormone thyrotropin prolactin and acth response to gonadotropin releasing hormone thyrotropin releasing hormone and l dopa in children with cooleys anemia thalassemia. IRCS (International Research Communications System) Medical Science Library Compendium 3(9): 499, 1975

Prolactin response to thyrotropin-releasing hormone (TRH) in patients with hypothalamic-pituitary disease. Fertility and Sterility 43(1): 66-73, 1985

Evidence that thyrotropin-releasing hormone and a hypothalamic prolactin-releasing factor may function in the release of prolactin in the lactating rat. Endocrinology 107(4): 863-868, 1980

Effects of thyrotropin releasing hormone and 3 methyl thyrotropin releasing hormone on body weight changes in holstein calves. Journal of Dairy Science 57(5): 607, 1974

Prolactin and thyrotropin in thyroid diseases: lack of evidence for a physiological role of thyrotropin-releasing hormone in the regulation of prolactin secretion. Hormone and Metabolic Research 6(3): 190-195, 1974

Serum thyroxine and prolactin with daily thyrotropin releasing hormone or 3 methyl thyrotropin releasing hormone. Journal of Animal Science 41(1): 369, 1975

Cyclic changes of pituitary thyrotropin releasing hormone receptor level and plasma prolactin response to thyrotropin releasing hormone in normal 4 day cycling female rats. Canadian Federation of Biological Societies Proceedings 19: 111, 1976