Prolactin Mediates Photoperiodic Immune Enhancement: Effects of Administration of Exogenous Prolactin on Circulating Concentrations, Receptor Expression, and Immune Function in Steers1
- 1 December 2004
- journal article
- Published by Oxford University Press (OUP) in Biology of Reproduction
- Vol. 71 (6), 1913-1918
- https://doi.org/10.1095/biolreprod.104.031005
Abstract
Changes in photoperiod can significantly impact the physiology of many species. For example, we have observed an improvement in cellular immune function in cattle on short-day photoperiod (SDPP) relative to long-day photoperiod (LDPP). In addition, prolactin (PRL) and PRL receptor (PRL-R) are affected by photoperiod management. Our hypothesis is that the inverse relationship observed between PRL and PRL-R mRNA expression during photoperiod treatment alters the sensitivity of the animal to PRL, thereby affecting the changes in their cellular immune function. The objective of this study was to determine the effects of exogenous PRL on photoperiodic-mediated immune responses. Eight Holstein steers received each of four treatments: LDPP (16L:8D), SDPP (8L:D), SDom (SDPP plus PRL via osmotic minipump for 10 days), and SDinj (SDPP plus PRL via 3× daily injections for 10 days). Steers on SDPP had decreased PRL relative to the other treatments. Expression of PRL-R mRNA was increased in SDPP animals relative to LDPP, SDom, and SDinj. Prior to PRL treatment, SDPP animals had greater lymphocyte proliferation and neutrophil chemotaxis relative to LDPP animals. Following PRL treatment, cellular immune function of SDom and SDinj animals was reduced to the level of LDPP animals. Addition of PRL to the in vitro lymphocyte proliferation did not alter response of LDPP animals but increased proliferation of lymphocytes from SDPP animals. The results of these experiments suggest that an animal's responsiveness to PRL correlate to changes in cellular immune function that occur with photoperiod manipulation.Keywords
This publication has 20 references indexed in Scilit:
- Short day lengths attenuate the symptoms of infection in Siberian hamstersProceedings Of The Royal Society B-Biological Sciences, 2002
- Effects of Photoperiodic Manipulation During the Dry Period of Dairy CowsJournal of Dairy Science, 2000
- Prolactin, growth hormone and the immune system in humansCellular and Molecular Life Sciences, 1998
- Prolactin Receptor Heterogeneity in Bovine Fetal and Maternal Tissues1Endocrinology, 1997
- Regulation of prolactin receptor mRNA expression in peripheral lymphocytes in rats in response to changes in serum concentrations of prolactin.Endocrinology, 1995
- Heat and social stress effects on pig immune measures1Journal of Animal Science, 1994
- Effect of exogenous prolactin administration on lactational performance of dairy cowsDomestic Animal Endocrinology, 1987
- Growth and Hormonal Response of Heifers to Various PhotoperiodsJournal of Animal Science, 1980
- Clearance and Secretion Rates of Prolactin in Dairy Cattle in Various Physiological StatesExperimental Biology and Medicine, 1980
- Hypophysial Responses to Continuous and Intermittent Delivery of Hypothalamic Gonadotropin-Releasing HormoneScience, 1978