Endocrine Abstracts

Differential changes in placental or fetal growth can result from chronic alterations in the environment depending on their timing and duration. These include thermal stimulation and/or altered photoperiod whose effects may be mediated in part by increased maternal food intake and/or repartitioning of available nutrients across the placenta. Fetal growth can subsequently be enhanced due to increased abundance of fetal anabolic hormones including prolactin. In particular, fetal...

Uncoupling protein-2 (UCP2) has many postulated functions, including possible solute exchange and immunity within the neonatal lung. The effect of maternal nutrition during late gestation on UCP2 abundance in the ovine neonatal lung has not been determined.Twin-bearing ewes of similar age and body weight were individually housed from 110 days gestation. Six controls (C) were fed and consumed 100% of their energy requirements for maintenance and growth of...

Introduction: Fetal fat comprises both brown and white adipocytes. Brown fat possess a unique uncoupling protein 1 (UCP1), whose abundance is regulated in part by the prolactin receptor (PRLR), whereas white fat is characterised as secreting leptin. The present study aimed to determine if the relationship between mRNA abundance for each of these molecular indices of adipose tissue function was nutritionally regulated.Methods: Twenty singleton-bearing ewe...

Introduction: In lambs, the rapid increase in heat production after birth is due to the initiation of nonshivering thermogenesis in brown adipose tissue (BAT). This occurs in conjunction with an increase in amount and activity of the BAT specific uncoupling protein 1 (UCP1). Both mRNA and protein for the long and short forms of the prolactin receptor are highly abundant in ovine BAT up to the time of birth. The following study aimed to determine whether prolactin administratio...

Introduction: Maternal dexamethasone (DEX) treatment is known to promote thermoregulation in the newborn lamb by increasing the amount of uncoupling protein 1 (UCP1). The extent to which the IGF axis within adipose tissue (AT) may be altered following such treatment is not known.Methods: Eight triplet bearing ewes were entered into the study, 5 of which were injected with 16 micrograms of DEX at 138 days of gestation (term = 147 days). Caesarean section ...

Fetal stress, including inadequate nutrient supply and cessation of fetal growth, are major stimuli to the onset of parturition which acts to promote maturation of the hypothalamic-pituitary axis. These adaptations, together with rapid removal of lung liquid fluid and onset of endogenous heat production at birth, ensure oxygen supply is adequate and hypothermia prevented. A critical component of fetal organ maturation in preparation for life after birth is mitochondrial develo...

Maternal cold exposure induced by winter shearing promotes fetal growth, particularly that of the liver by increasing maternal glucose supply to the fetus. A major component of the fetal liver is glycogen which is rapidly mobilized at birth in order to provide an endogenous energy source. Hepatic glyocgen content is regulated in part by the lipid activated transcription factor, peroxisome proliferator-activated receptor alpha (PPARα), whilst insulin-like growth factor (IG...

Fetal adipose tissue growth is a coordinated process involving the growth hormone-insulin-like growth factor (GH-IGF) axis. Maternal cold exposure (CE) induced by winter shearing can promote fetal fat growth depending on maternal food. The following study examined the interaction between maternal CE and dietary intake on the mRNA abundance for the endogenous ligand of the GH secretagogue receptor (GHSR-1a), the IGF-I and II receptors and the enzyme glycerol-3-phosphatase (G3P)...

IGF-II and I are key components of postnatal growth and are involved in the proliferation of adipocytes. Cold exposure by winter shearing has been shown to promote growth and development and is dependant upon maternal nutrition. However, the effects on adipose IGF-I and II mRNA have not yet been determined.Thirty-three multiparous ewes of similar body weight were entered into the study, fifteen were shorn (S) during mid gestation and eighteen left unshor...

Maternal nutrient restriction (NR) during late-gestation can influence liver growth by altering maturation of the hypothalamus. Maternal NR during late-gestation increases fetal plasma GH levels whilst circulating IGF-I and IGF-II levels decrease. This study aimed to determine whether maternal NR during late-gestation altered the hepatic IGF system in resultant offspring.Fourteen primiparous twin pregnant Border Leicester cross Swaledale ewes were fed <i...