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Universität Bonn
Landwirtschaftliche Fakultät
Dr. med. vet. Susanne Plattes

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Sie sind hier: Startseite Publikationen Adiponectin in Cattle: Profiling of molecular weight patterns in different body fluids at different physiological states and assessment of adiponectin’s effects on lymphocytes

Johanna FL Heinz (2014)

Adiponectin in Cattle: Profiling of molecular weight patterns in different body fluids at different physiological states and assessment of adiponectin’s effects on lymphocytes

Dissertation, Bonn.

Adiponectin (AdipoQ), one of the most abundant adipokines found in circulation exerts various meta-bolic functions, e.g. improving insulin sensitivity and ameliorating tissue inflammation. It is secreted in different molecular weight (MW) forms: a low molecular weight (LMW) trimer, a middle molecular weight (MMW) hexamer and a high molecular weight (HMW) form which is built of 12 to 18 mono-mers. Dairy cows undergo various metabolic changes in the time from late pregnancy to early lacta-tion. This causes a mobilization of body reserves which may lead to a higher risk for infectious diseas-es and possible problems in fertility later. The aims of this thesis were (1) to establish a semi-quantitative Western blot to estimate AdipoQ concentrations in serum and milk of lactating dairy cows; (2) to develop a semi-native Western blot to differentiate AdipoQ MW patterns in several bo-vine body fluids and tissues. (3) to estimate potential influences of AdipoQ on lymphocyte function; for this purpose AdipoQ was recombinantly expressed in Escherichia coli. First, the AdipoQ serum concentration in late pregnancy and the entire lactation as well as the concen-trations in milk from d 1 to d 24 in lactation were estimated. Subsequently, a profile of the AdipoQ MW forms in serum and milk of dairy cows at different time points in lactation was generated. Fur-thermore, the MW patterns of AdipoQ in two different adipose tissue (AT) depots (visceral and subcu-taneous) at three different days (1, 42, and 105) after parturition were investigated. In addition the MW patterns of AdipoQ in the mammary gland were shown. The AdipoQ MW forms in cerebrospinal fluid (CSF) and corresponding serum of transition cows were characterized. Moreover the AdipoQ MW patterns in other Bovidae, i.e.Yak, Bison and Water buffalo were characterized. As body fluids in rela-tion to reproduction we investigated the AdipoQ MW patterns in allantoic fluid (AF) and correspond-ing maternal serum. In addition the AdipoQ concentrations and MW patterns in seminal plasma (SP) of bulls and follicular fluid (FF) of heifers were evaluated. Independent of the MW patterns, the func-tional effect of recombinant AdipoQ on lymphocyte proliferation was studied. Adiponectin concentration in serum and milk showed an inverse course. Serum AdipoQ decreased until parturition and increased in early lactation, whereas AdipoQ concentration in milk was highest at the onset of lactation and decreased reaching a nadir in the first week of lactation. The changes in cir-culating AdipoQ are probably related with the hormonal changes associated with parturition. The MW patterns of serum and milk showed a prominent MMW band and a faint HMW band. In contrast to the MW patterns observed in humans we speculate that the MMW form of AdipoQ might be the most abundant one in cattle; in Yak, Bison and Water buffalo, the MMW AdipoQ was also the most promi-nent one. Different AT and mammary gland homogenates showed no differences in molecular weight pattern of AdipoQ. At each stage of lactation the HMW and the MMW band was detectable. CSF and serum samples of individual days in transition period showed no apparent differences in the MW pat-tern of AdipoQ. The AdipoQ MW pattern in AF was different to the AdipoQ MW pattern seen in se-rum before. AdipoQ was mainly detected as the HMW form, which might indicate that AF AdipoQ is not derived from circulation and might be of fetal origin. In bulls AdipoQ serum concentrations corre-lated with the ones in SP and the MW distribution was mainly the same. AdipoQ MW pattern in FF of heifers was different to the serum MW pattern; The HMW band was virtually absent in FF independ-ent of the stage of the estrous cycle. Recombinant AdipoQ reduced mitogen induced lymphocyte pro-liferation which indicates that AdipoQ might be involved in the immune suppression. The results of this thesis provide AdipoQ profiles in several bovine body fluids. The physiological function of the individual AdipoQ isoforms needs to be further investigated.
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