Evaluation of Serotonin as a Feedback Inhibitor of Lactation in the Bovine

Hernández, Laura; Stiening, Chad M.; Jb, Wheelock; Baumgard, Lance H.; Parkhurst, A. M.; Collier, Robert J.

doi:10.3168/jds.2007-0766

Cited by 70 publications

(80 citation statements)

References 14 publications

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“…In 2007, the same group (Stull et al, 2007) showed that 5-HT signaling in human and mouse cells caused the opening of tight epithelial junctions, a known hallmark of mammary gland involution. In 2008, two papers suggested that the mammary gland 5-HT system might be functional in dairy cows; Hernandez et al (2008), provided evidence of serotonin biosynthesis in cow mammary gland cells and demonstrated effects on milk variables when either 5-HT or a 5-HT receptor blocker was infused into the gland. Zhang et al (2008) showed that genetic mutations of one of the 5-HT receptors (5-HT1B) corresponded to increased milk yield.…”

Section: Altered Dry Periodsmentioning

confidence: 99%

Effects of continuous lactation and short dry periods on mammary function and animal health

Collier

Annen-Dawson

Pezeshki

2012

Animal

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The dry period is required to facilitate cell turnover in the bovine mammary gland in order to optimize milk yield in the next lactation. Traditionally, an 8-week dry period has been a standard management practice for dairy cows based on retrospective analyses of milk yields following various dry period lengths. However, as milk production per cow has increased, transitioning cows from the nonlactating state to peak milk yield has grown more problematic. This has prompted new studies on dry period requirements for dairy cows. These studies indicate a clear parity effect on dry period requirement. First parity animals require a 60-day dry period, whereas lactations following later parities demonstrate no negative impact with 30-day dry period or even eliminating the dry period when somatotropin (ST) is also used to maintain milk yields. Shortened dry periods in first parity animals were associated with reduced mammary cell turnover during the dry period and early lactation and increased numbers of senescent cells and reduced functionality of lactating alveolar mammary cells postpartum. Use of ST and increased milking frequency postpartum reduced the impact of shortened dry periods. The majority of new intramammary infections occur during the dry period and persist into the following lactation. There is therefore the possibility of altering mastitis incidence by modifying or eliminating the dry period in older parity animals. As the composition of mammary secretions including immunoglobulins may be reduced when the dry period is reduced or eliminated, there is the possibility that the immune status of cows during the peripartum period is influenced by the length of the dry period.

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Section: Altered Dry Periodsmentioning

confidence: 99%

Effects of continuous lactation and short dry periods on mammary function and animal health

Collier

Annen-Dawson

Pezeshki

2012

Animal

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“…In contrast, inhibiting serotonin synthesis or blocking its receptor increased milk protein gene expression (Hernandez et al, 2008). Further, intramammary infusion of serotonin reduced milk synthesis, whereas blocking the receptor increased milk synthesis in multiparous Holstein cows (Hernandez et al, 2008). Somatotropin treatment of mice decreased mammary expression of tryptophan hydroxylase 1 (Hadsell et al, 2008).…”

Section: The Circadian Systemmentioning

confidence: 99%

“…summer months). These increases in plasma IGF-1 occurred despite large decreases in feed intake and energy balance due to thermal stress (Collier et al, 2008). Collier et al (2008) suggested that the observed seasonal patterns in plasma IGF-I may be indicative of seasonal differences in the coupling of the somatotropin-IGF axis, as there was no evidence for an uncoupling of the somatotropin-IGF-I axis in summer despite an induced negative energy balance during thermal stress.…”

mentioning

confidence: 99%

“…These increases in plasma IGF-1 occurred despite large decreases in feed intake and energy balance due to thermal stress (Collier et al, 2008). Collier et al (2008) suggested that the observed seasonal patterns in plasma IGF-I may be indicative of seasonal differences in the coupling of the somatotropin-IGF axis, as there was no evidence for an uncoupling of the somatotropin-IGF-I axis in summer despite an induced negative energy balance during thermal stress.The increase in mammary parenchyma due to LDPP may also be mediated in part by changes in the mammary clock. In rodents, expression of core clock genes and c-Myc and Cyclin D1, which regulate cell division and show circadian patterns of expression, change with mammary development and differentiation.…”

mentioning

confidence: 99%

“…Addition of serotonin to mammosphere cultures reduced the expression of a-lactalbumin and casein genes. In contrast, inhibiting serotonin synthesis or blocking its receptor increased milk protein gene expression (Hernandez et al, 2008). Further, intramammary infusion of serotonin reduced milk synthesis, whereas blocking the receptor increased milk synthesis in multiparous Holstein cows (Hernandez et al, 2008).…”

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confidence: 99%

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Does the circadian system regulate lactation?

Plaut

Casey

2012

Animal

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Environmental variables such as photoperiod, heat, stress, nutrition and other external factors have profound effects on quality and quantity of a dairy cow's milk. The way in which the environment interacts with genotype to impact milk production is unknown; however, evidence from our laboratory suggests that circadian clocks play a role. Daily and seasonal endocrine rhythms are coordinated in mammals by the master circadian clock in the hypothalamus. Peripheral clocks are distributed in every organ and coordinated by signals from the master clock. We and others have shown that there is a circadian clock in the mammary gland. Approximately 7% of the genes expressed during lactation had circadian patterns including core clock and metabolic genes. Amplitude changes occurred in the core mammary clock genes during the transition from pregnancy to lactation and were coordinated with changes in molecular clocks among multiple tissues. In vitro studies using a bovine mammary cell line showed that external stimulation synchronized mammary clocks, and expression of the core clock gene, BMAL1, was induced by lactogens. Female clock/ clock mutant mice, which have disrupted circadian rhythms, have impaired mammary development and their offspring failed to thrive suggesting that the dam's milk production was not adequate enough to nourish their young. We envision that, in mammals, during the transition from pregnancy to lactation the master clock is modified by environmental and physiological cues that it receives, including photoperiod length. In turn, the master clock coordinates changes in endocrine milieu that signals peripheral tissues. In dairy cows, it is clear that changes in photoperiod during the dry period and/or during lactation influences milk production. We believe that the photoperiod effect on milk production is mediated, in part by the 'setting' of the master clock with light, which modifies peripheral circadian clocks including the mammary core clock and subsequently impacts milk yield and may impact milk composition.Keywords: mammary, lactation, circadian rhythm, photoperiod, metabolism ImplicationsThe circadian system coordinates internal physiological processes in mammals and synchronizes these processes to the animal's environment. We review the literature and discuss recent findings from our laboratory and others that suggest the circadian system regulates lactation, including coordinating changes in the dam's physiology needed to initiate and maintain lactation and mediating the photoperiod effect on milk production. Identification of environmental and physiological inputs that affect genes that control circadian rhythms will enable development of approaches to alter gene expression to maximize production efficiency in farm animals. IntroductionNearly all physiological and behavioral functions of animals are rhythmic including secretion patterns of hormones, sleep-wake cycle, metabolism and core body temperature.A circadian rhythm is a roughly 24-h cycle in the biochemical, physiological or behaviora...

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